Significant accounting policies [Abstract]

Nature of the business

Note 1.- Nature of the business

Atlantica Yield plc (“Atlantica Yield” or the “Company”) was incorporated in England and Wales as a private limited company on December 17, 2013 under the name Abengoa Yield Limited. On March 19, 2014, the Company was re-registered as a public limited company, under the name Abengoa Yield plc. On May 13, 2016, the change of the Company´s registered name to Atlantica Yield plc was filed with the Registrar of Companies in the United Kingdom.

Atlantica Yield is a total return company that owns, manages and acquires renewable energy, efficient natural gas (previously denominated “conventional power”) , electric transmission lines and water assets focused on North America (the United States and Mexico), South America (Peru, Chile and Uruguay) and EMEA (Spain, Algeria and South Africa).

The Company’s largest shareholder is Abengoa S.A. (“Abengoa”), which, based on the most recent public information, currently owns a 41.47 % stake in Atlantica Yield. Abengoa does not consolidate the Company in its consolidated financial statements.

On June 18, 2014, Atlantica Yield closed its initial public offering issuing 24,850,000 ordinary shares. The shares were offered at a price of $29 per share, resulting in gross proceeds to the Company of $720,650 thousand. The underwriters further purchased 3,727,500 additional shares from the selling shareholder, a subsidiary wholly owned by Abengoa, at the public offering price less fees and commissions to cover over-allotments (“greenshoe”) driving the total proceeds of the offering to $828,748 thousand.

Prior to the consummation of the initial public offering, Abengoa contributed, through a series of transactions, which we refer to collectively as the “Asset Transfer,” ten concessional assets, certain holding companies and a preferred equity investment in Abengoa Concessoes Brasil Holding (“ACBH”), which is a subsidiary of Abengoa engaged in the development, construction, investment and management of contracted concessions in Brazil, comprised mostly of transmission lines. As consideration for the Asset Transfer, Abengoa received a 64.28% interest in Atlantica Yield and $655.3 million in cash, corresponding to the net proceeds of the initial public offering less $30 million retained by Atlantica Yield for liquidity purposes.

Atlantica Yield’s shares began trading on the NASDAQ Global Select Market under the symbol “ABY” on June 12, 2014. The symbol changed to “AY” on November 11, 2017.

During 2016, the Company closed the acquisition of a 13% stake in Solacor 1/2 from the JGC Corporation (“JGC”), which reduced the JGC´s ownership in Solacor 1/2 to 13%, and of an 80% stake in Fotovoltaica Solar Sevilla, S.A. (“Seville PV”) from Abengoa, a 1 MW solar photovoltaic plant in Spain.

On February 28, 2017, the Company closed the acquisition of a 12.5% interest in a 114-mile transmission line in the U.S. from Abengoa. The asset will receive a Federal Energy Regulatory Commission (“FERC”) regulated rate of return, and is currently under development, with Commercial Operation Date (“COD”) expected in 2020.

On July 20, 2017, the Company reached an agreement to acquire, subject to approvals from the relevant authorities in Peru, a 4 MW hydroelectric power plant in Peru for approximately $9 million.

The following table provides an overview of the concessional assets the Company owned as of December 31, 2017 (excluding the 12.5% interest in the transmission line in the U.S. acquired in February 2017):

Assets	Type	Ownership	Location	Currency⁽⁸⁾	Capacity (Gross)	Counterparty Credit Ratings⁽⁹⁾	COD*	Contract Years Left ⁽¹²⁾

Solana	Renewable (Solar)	100% Class B⁽¹⁾	Arizona (USA)	USD	280 MW	A-/A3/A-	4Q 2013	26

Mojave	Renewable (Solar)	100%	California (USA)	USD	280 MW	A-/A3/A-	4Q 2014	22

Solaben 2 & 3	Renewable (Solar)	70%⁽²⁾	Spain	Euro	2x50 MW	BBB+/Baa2/A-	3Q 2012 & 2Q 2012	20&19

Solacor 1 & 2	Renewable (Solar)	87%⁽³⁾	Spain	Euro	2x50 MW	BBB+/Baa2/A-	1Q 2012 & 1Q 2012	19

PS10/PS20	Renewable (Solar)	100%	Spain	Euro	31 MW	BBB+/Baa2/A-	1Q 2007 & 2Q 2009	14&16

Helioenergy 1 & 2	Renewable (Solar)	100%	Spain	Euro	2x50 MW	BBB+/Baa2/A-	3Q 2011& 4Q 2011	19

Helios 1 & 2	Renewable (Solar)	100%	Spain	Euro	2x50 MW	BBB+/Baa2/A-	3Q 2012& 3Q 2012	20

Solnova 1, 3 & 4	Renewable (Solar)	100%	Spain	Euro	3x50 MW	BBB+/Baa2/A-	2Q 2010 & 2Q 2010& 3Q 2010	17&17&18

Solaben 1 & 6	Renewable (Solar)	100%	Spain	Euro	2x50 MW	BBB+/Baa2/A-	3Q 2013	21

Kaxu	Renewable (Solar)	51%⁽⁴⁾	South Africa	Rand	100 MW	BB/Baa3/BB+⁽¹⁰⁾	1Q 2015	17

Palmatir	Renewable (Wind)	100%	Uruguay	USD	50 MW	BBB/Baa2/BBB-⁽¹¹⁾	2Q 2014	16

Cadonal	Renewable (Wind)	100%	Uruguay	USD	50 MW	BBB/Baa2/BBB-⁽¹¹⁾	4Q 2014	17

ACT	Efficient natural gas	100%	Mexico	USD	300 MW	BBB+/A3/ BBB+	2Q 2013	15

ATN	Transmission line	100%	Peru	USD	362 miles	BBB+/A3/BBB+	1Q 2011	23

ATS	Transmission line	100%	Peru	USD	569 miles	BBB+/A3/BBB+	1Q 2014	26

ATN 2	Transmission line	100%	Peru	USD	81 miles	Not rated	2Q 2015	15

Quadra 1	Transmission line	100%	Chile	USD	49 miles	Not rated	2Q 2014	17

Quadra 2	Transmission line	100%	Chile	USD	32 miles	Not rated	1Q 2014	17

Palmucho	Transmission line	100%	Chile	USD	6 miles	BBB+/Baa2/BBB+	4Q 2007	20

Skikda	Water	34.2%⁽⁵⁾	Algeria	USD	3.5 M ft3/day	Not rated	1Q 2009	16

Honaine	Water	25.5%⁽⁶⁾	Algeria	USD	7 M ft3/ day	Not rated	3Q 2012	20

Seville PV	Renewable (Solar)	80%⁽⁷⁾	Spain	Euro	1 MW	BBB+/Baa2/A-	3Q 2006	18

(1)

On September 30, 2013, Liberty Interactive Corporation invested $300,000 thousand in Class A membership interests in exchange for a share of the dividends and taxable loss generated by Solana. As a result of the agreement, Liberty Interactive Corporation will receive between 54.06% and 61.20% of both dividends and taxable loss generated, additional amounts until the date Liberty reaches a certain rate of return or the “Flip Date”, and 22.60% of both dividends and taxable loss generated thereafter.

(2)	Itochu Corporation, a Japanese trading company, holds 30% of the shares in each of Solaben 2 and Solaben 3.

(3)	JGC, a Japanese engineering company, holds 13% of the shares in each of Solacor 1 and Solacor 2.

(4)	Kaxu is owned by the Company (51%), Industrial Development Corporation of South Africa (29%) and Kaxu Community Trust (20%).

(5)	Algerian Energy Company, SPA owns 49% of Skikda and Valoriza Agua, S.L. owns the remaining 16.83%.

(6)	Algerian Energy Company, SPA owns 49% of Honaine and Valoriza Agua, S.L. owns the remaining 25.5%.

(7)	Instituto para la Diversificación y Ahorro de la Energía (“Idae”), a Spanish state owned company, holds 20% of the shares in Seville PV.

(8)	Certain contracts denominated in U.S. dollars are payable in local currency.

(9)	Reflects the counterparty’s credit ratings issued by Standard & Poor’s Ratings Services, or S&P, Moody’s Investors Service Inc., or Moody’s, and Fitch Ratings Ltd, or Fitch.

(10)	Refers to the credit rating of the Republic of South Africa. The offtaker is Eskom, which is a state-owned utility company in South Africa.

(11)	Refers to the credit rating of Uruguay, as UTE (Administración Nacional de Usinas y Transmisoras Eléctricas) is unrated.

(12)	As of December 31, 2017.

* Commercial Operation Date (“COD”).

On November 27, 2015 Abengoa, reported that, it filed a communication pursuant to article 5 bis of the Spanish Insolvency Law 22/2003 with the Mercantile Court of Seville nº 2. On November 8, 2016, the Judge of the Mercantile Court of Seville declared judicial approval of Abengoa´s restructuring agreement, extending the terms of the agreement to those creditors who had not approved the restructuring agreement.

On February 3, 2017, Abengoa announced it obtained approval from creditors representing 94% of its financial debt after the supplemental accession period. On March 31, 2017 Abengoa announced the completion of the restructuring. As a result, Atlantica Yield received Abengoa debt and equity instruments in exchange of the guarantee previously provided by Abengoa regarding the preferred equity investment in ACBH. In addition, the Company invested in Abengoa´s issuance of asset-backed notes (the “New Money 1 Tradable Notes”) in order to convert the junior status of the Abengoa debt received into senior debt (see Note 8).

The financing arrangement of Kaxu contained as of December 31, 2016 cross-default provisions related to Abengoa, such that debt defaults by Abengoa, subject to certain threshold amounts and/or a restructuring process, could trigger defaults under such project financing arrangement. In March 2017, the Company signed a waiver which gives clearance to cross-default that might have arisen from Abengoa insolvency and restructuring up to that date, but does not extend to potential future cross-default events.

The financing arrangement of Cadonal also contained cross-default provisions with Abengoa and a waiver was obtained in 2016, subject to certain conditions. These conditions were met in October 2017.

In addition, as of December 31, 2016 the financing arrangements of Kaxu, ACT, Solana and Mojave contained a change of ownership clause that would be triggered if Abengoa ceased to own at least 35% of Atlantica Yield's shares (30% in the case of Solana and Mojave). Based on the most recent public information, Abengoa currently owns 41.47% of Atlantica Yield shares and 41.44% of the outstanding shares have been pledged as guarantee of the New Money 1 Tradable Notes and loans. On November 1, 2017 Abengoa announced it has reached an agreement with Algonquin Power & Utilities Corp. (“Algonquin”) to sell a 25% stake in Atlantica Yield subject to conditions precedent. Additionally, Abengoa has communicated that it intends to sell its remaining 16.5% stake over the upcoming months in a private transaction subject to approval by the U.S. Department of Energy (the “DOE”). Algonquin has an option to purchase this remaining stake until March 2018. If Abengoa ceases to comply with its obligation to maintain its 30% ownership of Atlantica Yield 's shares, such reduced ownership would put the Company in breach of covenants under the applicable project financing arrangements.

In the case of Solana and Mojave, a forbearance agreement signed with the DOE in 2016 with respect to these assets allows reductions of Abengoa’s ownership of the shares of the Company if it results from (i) a sale or other disposition at any time pursuant and in connection with a subsequent insolvency proceeding by Abengoa, or (ii) capital increases by the Company. In other events of reduction of ownership by Abengoa below the minimum ownership threshold such as sales of stake in Atlantica Yield by Abengoa, the available DOE remedies will not include debt acceleration, but DOE remedies available could include limitations on distributions to the Company from Solana and Mojave. In addition, the minimum ownership threshold for Abengoa’s ownership of the shares of the Company has been reduced from 35% to 30%. In November 2017, in the context of the agreement reached between Abengoa and Algonquin for the acquisition by Algonquin of 25% of the shares of the Company and based on the obligations of Abengoa under the EPC contract the Company signed a consent with the DOE which reduces this minimum ownership required by Abengoa in Atlantica Yield to 16%, subject to certain conditions precedent most of which are beyond the control of Atlantica Yield (see Note 10).

In the case of Kaxu, in March 2017 the Company signed a waiver, which allows reduction of ownership by Abengoa below the 35% threshold if it is done in the context of the restructuring plan. Additionally, the Company obtained in October 2017 the waiver for ACT

Additionally, on February 10, 2017, the Company issued senior secured notes (the “Note Issuance Facility”) with a group of funds managed by Westbourne Capital as purchasers of the notes issued thereunder for a total amount of €275 million (approximately $330 million as of December 31, 2017). The proceeds of the Note Issuance Facility were used to fully repay Tranche B under the Company´s Credit Facility, which was then canceled (see Note 14).

These consolidated financial statements were approved by the Board of Directors of the Company on February 27, 2018.

Significant accounting policies

12 Months Ended

Dec. 31, 2017

Significant accounting policies

Note 2.- Significant accounting policies

2.1 Basis of preparation

These consolidated financial statements are presented in accordance with the International Financial Reporting Standards (“IFRS”) as issued by the International Accounting Standards Board (“IASB”).

The Company entered into an agreement with Abengoa on June 13, 2014 (the “ROFO Agreement”), as amended and restated on December 9, 2014, that provides the Company with a right of first offer on any proposed sale, transfer or other disposition of any of Abengoa’s contracted renewable energy, efficient natural gas, electric transmission or water assets in operation and located in the United States, Canada, Mexico, Chile, Peru, Uruguay, Brazil, Colombia and the European Union, as well as four assets in selected countries in Africa, the Middle East and Asia.

The Company elected to account for the assets acquisitions under the ROFO Agreement using the Predecessor values as long as Abengoa had control over the Company, given that these were transactions between entities under common control. Any difference between the consideration given and the aggregate book value of the assets and liabilities of the acquired entities as of the date of the transaction has been reflected as an adjustment to equity.

Abengoa has no control over the Company since December 31, 2015. Therefore, any acquisition from Abengoa is accounted for in the consolidated accounts of Atlantica Yield since December 31, 2015, in accordance with IFRS 3, Business Combination.

The consolidated financial statements are presented in U.S. dollars, which is the Company’s functional and presentation currency. Amounts included in these consolidated financial statements are all expressed in thousands of U.S. dollars, unless otherwise indicated.

Application of new accounting standards

a)	Standards, interpretations and amendments effective from January 1, 2017 under IFRS-IASB, applied by the Company in the preparation of these consolidated financial statements:

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IAS 7 (Amendment) ‘Disclosure Initiative’. Requirements for additional disclosures in order to provide users with improved financial information.

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IAS 12 (Amendment) ‘Recognition for Deferred Tax for Unrealized Losses’. Clarification of recognition of deferred tax assets for unrealized losses.

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Annual Improvements to IFRSs 2014-2016 cycles. Amendments to IFRS 12.

The applications of these amendments have not had any material impact on these consolidated financial statements except for the reconciliation of liabilities arising from financial activities that has been included in Note 14 and 15.

b)	Standards, interpretations and amendments published by the IASB that will be effective for periods beginning on or after January 1, 2018:

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IFRS 9 ‘Financial Instruments’. This Standard is applicable for annual periods beginning on or after January 1, 2018 under IFRS-IASB, earlier application is permitted.

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IFRS 9 (Amendments to IFRS 9): Prepayment Features with Negative Compensation. This Standard is applicable for annual periods beginning on or after January 1, 2019 under IFRS-IASB, earlier application is permitted.

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IFRS 15 ‘Revenues from Contracts with Customers’. This Standard is applicable for annual periods beginning on or after January 1, 2018 under IFRS-IASB, earlier application is permitted.

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IFRS 15 (Clarifications) ‘Revenues from Contracts with Customers’. This amendment is mandatory for annual periods beginning on or after January 1, 2018 under IFRS-IASB, earlier application is permitted.

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IFRS 16 ‘Leases’. This Standard is applicable for annual periods beginning on or after January 1, 2019 under IFRS-IASB, earlier application is permitted.

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IFRS 17 ‘Insurance Contracts’. This Standard is applicable for annual periods beginning on or after January 1, 2021 under IFRS-IASB, earlier application is permitted.

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IFRS 2 (Amendment) ‘Classification and Measurement of Share-based Payment Transactions’. This amendment is mandatory for annual periods beginning on or after January 1, 2018 under IFRS-IASB, earlier application is permitted.

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IFRS 4 (Amendment). Applying IFRS 9 ‘Financial Instruments’ with IFRS 4 ‘Insurance Contracts’. This amendment is mandatory for annual periods beginning on or after January 1, 2018 under IFRS-IASB, earlier application is permitted.

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IAS 40 (Amendment). Transfers of Investment Property. This amendment is mandatory for annual periods beginning on or after January 1, 2018 under IFRS-IASB, earlier application is permitted.

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IAS 19 (Amendment). Amendments to IAS 19: Plan Amendment, Curtailment or Settlement. This amendment is mandatory for annual periods beginning on or after January 1, 2019 under IFRS-IASB, earlier application is permitted.

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IAS 28 (Amendment). Long-term Interests in Associates and Joint Ventures. This amendment is mandatory for annual periods beginning on or after January 1, 2018 under IFRS-IASB, earlier application is permitted.

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Annual Improvements to IFRSs 2014-2016 cycles. Other minor amendments and modifications different from the aforementioned on IFRS 12. This Standard is applicable for annual periods beginning on or after January 1, 2018 under IFRS-IASB.

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Annual Improvements to IFRSs 2015-2017 cycles. This Standard is applicable for annual periods beginning on or after January 1, 2018 under IFRS-IASB.

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IFRIC 22 Foreign Currency Transactions and Advance Consideration. This Standard is applicable for annual periods beginning on or after January 1, 2018 under IFRS-IASB.

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IFRIC 23 Uncertainty over Income Tax Treatments. This Standard is applicable for annual periods beginning on or after January 1, 2019 under IFRS-IASB.

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IFRS 10 and IAS 28. Parent disposes of (or contributes) its controlling interest in a subsidiary to an existing associate or joint venture. Effective date beginning on or after a date to be determined by the IASB.

The application of these accounting standards is not expected to have a material impact on the consolidated financial statements of the Company.

The analysis performed by the Company, relating to the impact of the new relevant accounting standards is as follows:

IFRS 15 ‘Revenues from contracts with Customers’

In May 2014, the IASB (International Accounting Standards Board) published IFRS 15 “Recognition of Revenue from Contracts with Customers”. This Standard brings together all the applicable requirements and replaces the current standards for recognizing revenue: IAS 11 Construction Contracts, IAS 18 Revenue, IFRIC 13 Customer Loyalty Program, IFRIC 15 Agreements for the Construction of Real Estate, IFRIC 18 Transfers of Assets from Customers and SIC-31 Revenue—Barter Transactions Involving Advertising Services.

The new requirements may lead to changes in the current revenue profile, since the Standard's main principle is that the Company must recognize its revenue in accordance with the transfer of goods or services to the customers in an amount which reflects the consideration that the Company expects to receive in exchange for these goods or services. The model laid out by the Standard is structured in five steps:

Step 1: Identifying the contract with the customer.

Step 2: Identifying the performance obligations.

Step 3: Determining the transaction price.

Step 4: Assigning the transaction price in the performance obligations identified in the contract.

Step 5: Recognition of revenue when (or as) the Company performs the performance obligations.

Contracted concessional assets and price purchase agreements (PPAs) include fixed assets financed through project debt, related to service concession arrangements recorded in accordance with International Financial Reporting Interpretations Committee 12 (“IFRIC 12”), except for Palmucho, which is recorded in accordance with IAS 17 and PS10, PS20 and Seville PV, which are recorded as tangible assets in accordance with IAS 16. The infrastructures accounted for by the Company as concessions are related to the activities concerning electric transmission lines, solar electricity generation plants, cogeneration plants, wind farms and water plants.

Currently, assets recorded in accordance with IFRIC 12 are classified as intangible assets or as financial assets, depending on the nature of the payment entitlements established in the contracts.

According to IFRS 15, the Company should assess the goods and services promised in the contracts with the customers and shall identify as a performance obligation each promise to transfer to the customer a good or service (or a bundle of goods or services).

In the case of contracts related to financial assets, the Company has identified two performance obligations (construction and operation of the asset). The contracts state that each service (construction and operation) has its own transaction price. For this reason, both performance obligations are separately identifiable in the context of the contract. The Company must allocate the total consideration to be received by the contract to each performance obligation. As mentioned above, the different services performed have been identified as two different performance obligations (construction and operation). Each performance obligation has its own transaction price stated in the contract. Such transaction prices are agreed in the contract by the parties in an orderly transaction, with no interrelation between both transaction prices and therefore correspond to the fair value of the goods and services provided in each case. As a result, for IFRS 15 purposes, the total transaction price will be allocated to each performance obligation in accordance with the two transaction prices stated within the contract, as they represent the respective fair values of the identified performance obligations.

For the assets classified as intangible assets, the Company has identified the same performance obligations, (construction and operation), but in this case the consideration received by the Company for the construction services is a license. The grantor makes a non-cash payment for the construction services by giving the operator an intangible asset. When allocating fair value for IFRS 15 purposes, the Company will recognize as revenue for the first performance obligation the fair value of the construction services, and the amount corresponding to the sales of energy as the fair value of second performance obligation (operation).

Additionally, in both cases, the services are satisfied over time. Therefore, the Company satisfies the performance obligations and recognizes revenue over time. The same conclusion applies to concessional assets that are classified as tangible assets or leases.

IFRS 15 also incorporates specific criteria to determine which costs relating to a contract should be capitalized by distinguishing between incremental costs of obtaining a contract and costs associated with fulfilling a contract. No significant costs of obtaining a contract or compliance (other than those that are already capitalized) have been identified.

As the current practice for revenue recognition is consistent with the analysis above under IFRS 15, the Company considers that the adoption of this standard will not have impact in the consolidated financial statements of the Company.

Also, the Company has the intention to adopt IFRS 15 applying the full retrospective method to each prior reporting period presented, but without changes in the comparative reporting periods as the adoption of the standard has no effect in the financial statements.

IFRS 9 ‘Financial Instruments’

IFRS 9 Financial Instruments issued on 24 July 2014 is the IASB's replacement of IAS 39 Financial Instruments: Recognition and Measurement. The standard addresses the classification, measurement and derecognition of financial assets and financial liabilities, introduces new rules for hedge accounting and a new impairment model for financial assets. The Company will be adopting the standard as of January 1, 2018, including the new requirements for hedge accounting (which application is voluntary for 2018). The Company will be adopting retrospectively without re-expressing comparative periods. The analysis performed by the Company is as follows:

Classification and measurement of financial instruments:

Financial assets IFRS 9 classifies all financial assets that are currently in the scope of IAS 39 into two categories: amortized cost and fair value. Where assets are measured at fair value, gains and losses are either recognized entirely in profit or loss (fair value through profit or loss, “FVTPL”), or recognized in other comprehensive income (fair value through other comprehensive income, “FVTOCI”). The new guidance has no significant impact on the classification and measurement of the financial assets of the Company as the vast majority of financial assets (except for derivatives) are currently measured at amortized cost, and meet the conditions for classification at amortized cost under IFRS9. The Company has the intention of maintaining this classification.

Financial liabilities: IFRS 9 does not change the basic accounting model for financial liabilities under IAS 39. Two measurement categories continue to exist: FVTPL and amortized cost. Financial liabilities held for trading are measured at FVTPL, and all other financial liabilities are measured at amortized cost unless the fair value option is applied. As a result, the Company concluded that there will be no significant impact on the consolidated financial statements.

The new impairment model requires the recognition of impairment provisions based on expected credit losses (“ECL”) rather than only incurred credit losses as is the case under IAS 39. The Company reviewed its portfolio of financial assets subject to the new model of impairment under the new methodology (using credit default swaps, rating from credit agencies and other external inputs in order to estimate the probability of default), and concluded that initial impact on the consolidated financial statements is not significant.

The accounting for certain modifications and exchanges of financial liabilities measured at amortized cost (e.g. bank loans and issued bonds) will change on the transition from IAS 39 to IFRS 9. This change arises from a clarification by the IASB in the Basis for Conclusions of IFRS 9. Under IFRS 9 it is now clear that there can be an effect in the income statement for modification and exchanges of financial liabilities that are considered “non-substantial” (when the net present value of the cash flows, including any fees paid net of any fees received, is lower than 10% different from the net present value of the remaining cash flows of the liability prior to the modification, both discounted at the original effective interest rate). The Company reviewed retrospectively these transactions and concluded that the impact is not significant.

IFRS 9 also introduces changes in hedge accounting. The hedge accounting requirements in IFRS 9 are optional and tend to facilitate the use of hedge accounting by preparers of financial statements. As a result, the Company reviewed its portfolio of derivatives and concluded that there will not be significant impact on its consolidated financial statements as a result of applying IFRS 9.

The new standard will require some new disclosures, in particular regarding hedge accounting, credit risk and ECLs that will be presented in future periods.

IFRS 16 ‘Leases’

The IASB issued a new lease accounting standard, IFRS 16, in January 2016, which will require the recognition of lease contracts on the consolidated statement of financial position.

IFRS 16 eliminates the classification of leases as either operating leases or finance leases for a lessee. Instead all leases are treated in a similar way to finance leases applying IAS 17. Leases are ‘capitalized’ by recognizing the present value of the lease payments and showing them either as lease assets (right-of-use of assets) or together with property, plant and equipment. If lease payments are made over time, a company also recognizes a financial liability representing its obligation to make future lease payments.

In the income statement, IFRS 16 replaces the straight-line operating lease expense for those leases applying IAS 17, with a depreciation charge for the lease asset (included within operating expenses) and an interest expense on the lease liability (included within finance expenses). IFRS 16 will also have an effect on the presentation of cash flows related to former off-balance sheet leases.

The Company performed its assessment of the impact on its consolidated financial statements. The most significant impact identified is that the Company will recognize new assets and liabilities for its existing operating leases of land rights, buildings, offices and equipment.

The standard is effective for annual periods beginning on or after January 1, 2019, with earlier application permitted for entities that apply IFRS 15 at or before the date of initial application of IFRS 16. The Company decided to early adopt the standard as of January 1, 2018.

An entity shall apply this standard using one of the following two methods: full retrospectively approach or a modified retrospective approach. The Company has chosen the latter and will account for assets as an amount equal to liability at the date of initial application. The Company estimates the impact on the consolidated statement of financial position as of January 1, 2018, is not significant (less than 1% of total assets).

2.2. Principles to include and record companies in the consolidated financial statements

Companies included in these consolidated financial statements are accounted for as subsidiaries as long as Atlantica Yield has had control over them and are accounted for as investments under the equity method as long as Atlantica Yield has had significant influence over them, in the periods presented.

Controlled entities

Control is achieved when the Company:

Has power over the investee;

Is exposed, or has rights, to variable returns from its involvement with the investee; and

Has the ability to use its power to affect its returns.

The Company reassesses whether or not it controls an investee when facts and circumstances indicate that there are changes to one or more of the three elements of control listed above.

The Company uses the acquisition method to account for business combinations of companies controlled by a third party. According to this method, identifiable assets acquired and liabilities and contingent liabilities assumed in a business combination are measured initially at their fair values at the acquisition date. Any contingent consideration is recognized at fair value at the acquisition date and subsequent changes in its fair value are recognized in accordance with IAS 39 either in profit or loss or as a change to other comprehensive income. Acquisition related costs are expensed as incurred. The Company recognizes any non-controlling interest in the acquiree either at fair value or at the non-controlling interest’s proportionate share of the acquirer’s net assets on an acquisition by acquisition basis.

Acquisitions of businesses from Abengoa were until December 31, 2015, not considered business combinations, as Atlantica Yield was a subsidiary controlled by Abengoa. The assets acquired constituted an acquisition under common control by Abengoa and accordingly, were recorded using Abengoa’s historical basis in the assets and liabilities of the Predecessor. Abengoa has no control over the Company since December 31, 2015. Therefore, any purchase from Abengoa is accounted for in the consolidated accounts of Atlantica Yield since December 31, 2015, in accordance with IFRS 3, Business Combination.

All assets and liabilities between entities of the group, equity, income, expenses, and cash flows relating to transactions between entities of the group are eliminated in full.

Investments accounted for under the equity method

An associate is an entity over which the Company has significant influence. Significant influence is the power to participate in the financial and operating policy decisions of the investee but is not control or joint control over those policies.

The results and assets and liabilities of associates are incorporated in these financial statements using the equity method of accounting. Under the equity method, an investment in an associate is initially recognized in the statement of financial position at cost and adjusted thereafter to recognize the Company share of the profit or loss and other comprehensive income of the associate.

Controlled entities and associates included in these financial statements as of December 31, 2017 and 2016 are set out in appendices.

2.3. Contracted concessional assets and price purchase agreements

Contracted concessional assets and price purchase agreements (PPAs) include fixed assets financed through project debt, related to service concession arrangements recorded in accordance with IFRIC 12, except for Palmucho, which is recorded in accordance with IAS 17 and PS10, PS20 and Seville PV, which are recorded as tangible assets in accordance with IAS 16. The infrastructures accounted for by the Company as concessions are related to the activities concerning electric transmission lines, solar electricity generation plants, cogeneration plants, wind farms and water plants. The useful life of these assets is approximately the same as the length of the concession arrangement. The infrastructure used in a concession can be classified as an intangible asset or a financial asset, depending on the nature of the payment entitlements established in the agreement.

The application of IFRIC 12 requires extensive judgment in relation with, among other factors, (i) the identification of certain infrastructures and contractual agreements in the scope of IFRIC 12, (ii) the understanding of the nature of the payments in order to determine the classification of the infrastructure as a financial asset or as an intangible asset and (iii) the timing and recognition of the revenue from construction and concessionary activity.

Under the terms of contractual arrangements within the scope of this interpretation, the operator shall recognize and measure revenue in accordance with IAS 11 and 18 for the services it performs. If the operator performs more than one service (i.e. construction or upgrade services and operation services) under a single contract or arrangement, consideration received or receivable shall be allocated by reference to the relative fair values of the services delivered, when the amounts are separately identifiable.

Intangible asset

The Company recognizes an intangible asset to the extent that it receives a right to charge final customers for the use of the infrastructure. This intangible asset is subject to the provisions of IAS 38 and is amortized linearly, taking into account the estimated period of commercial operation of the infrastructure which coincides with the concession period.

Once the infrastructure is in operation, the treatment of income and expenses is as follows:

Revenues from the updated annual revenue for the contracted concession, as well as operations and maintenance services are recognized in each period according to IAS 18 “Revenue”.

Operating and maintenance costs and general overheads and administrative costs are recorded in accordance with the nature of the cost incurred (amount due) in each period.

Financing costs are expensed as incurred.

Financial asset

The Company recognizes a financial asset when demand risk is assumed by the grantor, to the extent that the concession holder has an unconditional right to receive payments for the asset. This asset is recognized at the fair value of the construction services provided, considering upgrade services in accordance with IAS 11, if any.

The financial asset is subsequently recorded at amortized cost calculated according to the effective interest method. Revenue from operations and maintenance services is recognized in each period according to IAS 18 “Revenue”. The remuneration of managing and operating the asset resulting from the valuation at amortized cost is also recorded in revenue.

Financing costs are expensed as incurred.

Property, plant and equipment

Property, plant and equipment includes property, plant and equipment of companies or project companies. Property, plant and equipment is measured at historical cost, including all expenses directly attributable to the acquisition, less depreciation and impairment losses, with the exception of land, which is presented net of any impairment losses.

Once the infrastructure is in operation, the treatment of income and expenses is the same as the one described above for intangible asset.

2.4. Borrowing costs

Interest costs incurred in the construction of any qualifying asset are capitalized over the period required to complete and prepare the asset for its intended use. A qualifying asset is an asset that necessarily takes a substantial period of time to get ready for its internal use or sale, which is considered to be more than one year. Remaining borrowing costs are expensed in the period in which they are incurred.

2.5 Asset impairment

Atlantica Yield reviews its contracted concessional assets to identify any indicators of impairment at least annually.

The recoverable amount of an asset is the higher of its fair value less costs to sell and its value in use, defined as the present value of the estimated future cash flows to be generated by the asset. In the event that the asset does not generate cash flows independently of other assets, the Company calculates the recoverable amount of the Cash Generating Unit (‘CGU’) to which the asset belongs.

When the carrying amount of the CGU to which these assets belong is higher than its recoverable amount, the assets are impaired.

Assumptions used to calculate value in use include a discount rate, growth rate and projections considering real data based in the contracts terms and projected changes in both selling prices and costs. The discount rate is estimated by Management, to reflect both changes in the value of money over time and the risks associated with the specific CGU.

For contracted concessional assets, with a defined useful life and with a specific financial structure, cash flow projections until the end of the project are considered and no terminal value is assumed.

Contracted concessional assets have a contractual structure that permits the Company to estimate quite accurately the costs of the project (both in the construction and in the operations periods) and revenue during the life of the project.

Projections take into account real data based on the contract terms and fundamental assumptions based on specific reports prepared by experts, assumptions on demand and assumptions on production. Additionally, assumptions on macro-economic conditions are taken into account, such as inflation rates, future interest rates, etc. and sensitivity analyses are performed over all major assumptions which can have a significant impact in the value of the asset.

Cash flow projections of CGUs are calculated in the functional currency of those CGUs and are discounted using rates that take into consideration the risk corresponding to each specific country and currency.

Taking into account that in most CGUs the specific financial structure is linked to the financial structure of the projects that are part of those CGUs, the discount rate used to calculate the present value of cash-flow projections is based on the weighted average cost of capital (WACC) for the type of asset, adjusted, if necessary, in accordance with the business of the specific activity and with the risk associated with the country where the project is performed.

In any case, sensitivity analyses are performed, especially in relation with the discount rate used and fair value changes in the main business variables, in order to ensure that possible changes in the estimates of these items do not impact the possible recovery of recognized assets.

Accordingly, the following table provides a summary of the discount rates used (WACC) and growth rates to calculate the recoverable amount for CGUs with the operating segment to which it pertains:

Operating segment	Discount rate			Growth rate
EMEA		4% - 6	%		0	%
North America		4% - 6	%		0	%
South America		5% - 7	%		0	%

In the event that the recoverable amount of an asset is lower than its carrying amount, an impairment charge for the difference would be recorded in the income statement under the item “Depreciation, amortization and impairment charges”.

Pursuant to IAS 36, an impairment loss is recognized if the carrying amount of these assets exceeds the present value of future cash flows discounted at the initial effective interest rate.

2.6 Loans and accounts receivable

Loans and accounts receivable are non-derivative financial assets with fixed or determinable payments, not listed on an active market.

In accordance with IFRIC 12, certain assets under concessions qualify as financial assets and are recorded as is described in Note 2.3.

Pursuant to IAS 36, an impairment loss is recognized if the carrying amount of these assets exceeds the present value of future cash flows discounted at the initial effective interest rate.

Loans and accounts receivable are initially recognized at fair value plus transaction costs and are subsequently measured at amortized cost in accordance with the effective interest rate method. Interest calculated using the effective interest rate method is recognized under other financial income within financial income.

2.7. Derivative financial instruments and hedging activities

Derivatives are recorded at fair value. The Company applies hedge accounting to all hedging derivatives that qualify to be accounted for as hedges under IFRS-IASB.

When hedge accounting is applied, hedging strategy and risk management objectives are documented at inception, as well as the relationship between hedging instruments and hedged items. Effectiveness of the hedging relationship needs to be assessed on an ongoing basis. Effectiveness tests are performed prospectively and retrospectively at inception and at each reporting date, following the dollar offset method or the regression method, depending on the type of derivatives and the type of tests performed.

Atlantica Yield applies cash flow hedging. Under this method, the effective portion of changes in fair value of derivatives designated as cash flow hedges are recorded temporarily in equity and are subsequently reclassified from equity to profit or loss in the same period or periods during which the hedged item affects profit or loss. Any ineffective portion of the hedged transaction is recorded in the consolidated income statement as it occurs.

When interest rate options are designated as hedging instruments, the intrinsic value and time value of the financial hedge instrument are separated. Changes in intrinsic value which are highly effective are recorded in equity and subsequently reclassified from equity to profit or loss in the same period or periods during which the hedged item affects profit or loss. Changes in time value are recorded as financial income or expense, together with any ineffectiveness.

When the hedging instrument matures or is sold, or when it no longer meets the requirements to apply hedge accounting, accumulated gains and losses recorded in equity remain as such until the forecast transaction is ultimately recognized in the income statement. However, if it becomes unlikely that the forecast transaction will actually take place, the accumulated gains and losses in equity are recognized immediately in the income statement.

2.8. Fair value estimates

Financial instruments measured at fair value are presented in accordance with the following level classification based on the nature of the inputs used for the calculation of fair value:

Level 1: Inputs are quoted prices in active markets for identical assets or liabilities.

Level 2: Fair value is measured based on inputs other than quoted prices included within Level 1 that are observable for the asset or liability, either directly (i.e. as prices) or indirectly (i.e. derived from prices).

Level 3: Fair value is measured based on unobservable inputs for the asset or liability.

In the event that prices cannot be observed, the management shall make its best estimate of the price that the market would otherwise establish based on proprietary internal models which, in the majority of cases, use data based on observable market parameters as significant inputs (Level 2) but occasionally use market data that is not observed as significant inputs (Level 3). Different techniques can be used to make this estimate, including extrapolation of observable market data. The best indication of the initial fair value of a financial instrument is the price of the transaction, except when the value of the instrument can be obtained from other transactions carried out in the market with the same or similar instruments, or valued using a valuation technique in which the variables used only include observable market data, mainly interest rates. Differences between the transaction price and the fair value based on valuation techniques that use data that is not observed in the market, are not initially recognized in the income statement.

Atlantica Yield derivatives correspond primarily to the interest rate swaps designated as cash flow hedges, which are classified as Level 2:

Description of the valuation method

Interest rate swap valuations are made by valuing the swap part of the contract and valuing the credit risk. The methodology used by the market and applied by Atlantica Yield to value interest rate swaps is to discount the expected future cash flows according to the parameters of the contract. Variable interest rates, which are needed to estimate future cash flows, are calculated using the curve for the corresponding currency and extracting the implicit rates for each of the reference dates in the contract. These estimated flows are discounted with the swap zero curve for the reference period of the contract.

The effect of the credit risk on the valuation of the interest rate swaps depends on the future settlement. If the settlement is favorable for the Company, the counterparty credit spread will be incorporated to quantify the probability of default at maturity. If the expected settlement is negative for the Company, its own credit risk will be applied to the final settlement.

Classic models for valuing interest rate swaps use deterministic valuation of the future of variable rates, based on future outlooks. When quantifying credit risk, this model is limited by considering only the risk for the current paying party, ignoring the fact that the derivative could change sign at maturity. A payer and receiver swaption model is proposed for these cases. This enables the associated risk in each swap position to be reflected. Thus, the model shows each agent’s exposure, on each payment date, as the value of entering into the ‘tail’ of the swap, i.e. the live part of the swap.

Variables (Inputs)

Interest rate derivative valuation models use the corresponding interest rate curves for the relevant currency and underlying reference in order to estimate the future cash flows and to discount them. Market prices for deposits, futures contracts and interest rate swaps are used to construct these curves. Interest rate options (caps and floors) also use the volatility of the reference interest rate curve.

To estimate the credit risk of the counterparty, the credit default swap (CDS) spreads curve is obtained in the market for important individual issuers. For less liquid issuers, the spreads curve is estimated using comparable CDSs or based on the country curve. To estimate proprietary credit risk, prices of debt issues in the market and CDSs for the sector and geographic location are used.

The fair value of the financial instruments that results from the aforementioned internal models takes into account, among other factors, the terms and conditions of the contracts and observable market data, such as interest rates, credit risk and volatility. The valuation models do not include significant levels of subjectivity, since these methodologies can be adjusted and calibrated, as appropriate, using the internal calculation of fair value and subsequently compared to the corresponding actively traded price. However, valuation adjustments may be necessary when the listed market prices are not available for comparison purposes.

2.9. Clients and other receivables

Clients and other receivables are amounts due from customers for sales in the normal course of business. They are recognized initially at fair value and subsequently measured at amortized cost using the effective interest rate method, less allowance for doubtful accounts. Trade receivables due in less than one year are carried at their face value at both initial recognition and subsequent measurement, provided that the effect of not discounting flows is not significant.

An allowance for doubtful accounts is recorded when there is objective evidence that the Company will not be able to recover all amounts due as per the original terms of the receivables.

2.10. Cash and cash equivalents

Cash and cash equivalents include cash in hand, cash in bank and other highly-liquid current investments with an original maturity of three months or less which are held for the purpose of meeting short-term cash commitments.

2.11. Grants

Grants are recognized at fair value when it is considered that there is a reasonable assurance that the grant will be received and that the necessary qualifying conditions, as agreed with the entity assigning the grant, will be adequately complied with.

Grants are recorded as liabilities in the consolidated statement of financial position and are recognized in “Other operating income” in the consolidated income statement based on the period necessary to match them with the costs they intend to compensate.

In addition, as described in Note 2.12 below, grants correspond also to loans with interest rates below market rates, for the initial difference between the fair value of the loan and the proceeds received.

2.12. Loans and borrowings

Loans and borrowings are initially recognized at fair value, net of transaction costs incurred. Borrowings are subsequently measured at amortized cost and any difference between the proceeds initially received (net of transaction costs incurred in obtaining such proceeds) and the repayment value is recognized in the consolidated income statement over the duration of the borrowing using the effective interest rate method.

Loans with interest rates below market rates are initially recognized at fair value in liabilities and the difference between proceeds received from the loan and its fair value is initially recorded within “Grants and Other liabilities” in the consolidated statement of financial position, and subsequently recorded in “Other operating income” in the consolidated income statement when the costs financed with the loan are expensed.

2.13. Bonds and notes

The Company initially recognizes ordinary notes at fair value, net of issuance costs incurred. Subsequently, notes are measured at amortized cost until settlement upon maturity. Any other difference between the proceeds obtained (net of transaction costs) and the redemption value is recognized in the consolidated income statement over the term of the debt using the effective interest rate method.

2.14. Income taxes

Current income tax expense is calculated on the basis of the tax laws in force as of the date of the consolidated statement of financial position in the countries in which the subsidiaries and associates operate and generate taxable income.

Deferred income tax is calculated in accordance with the liability method, based upon the temporary differences arising between the carrying amount of assets and liabilities and their tax base. Deferred income tax is determined using tax rates and regulations which are expected to apply at the time when the deferred tax is realized.

Deferred tax assets are recognized only when it is probable that sufficient future taxable profit will be available to use deferred tax assets.

2.15. Trade payables and other liabilities

Trade payables are obligations arising from purchases of goods and services in the ordinary course of business and are recognized initially at fair value and are subsequently measured at their amortized cost using the effective interest method. Other liabilities are obligations not arising in the normal course of business and which are not treated as financing transactions. Advances received from customers are recognized as “Trade payables and other current liabilities”.

2.16. Foreign currency transactions

The consolidated financial statements are presented in U.S. dollars, which is Atlantica Yield functional and reporting currency. Financial statements of each subsidiary within the Company are measured in the currency of the principal economic environment in which the subsidiary operates, which is the subsidiary’s functional currency.

Transactions denominated in a currency different from the subsidiary’s functional currency are translated into the subsidiary’s functional currency applying the exchange rates in force at the time of the transactions. Foreign currency gains and losses that result from the settlement of these transactions and the translation of monetary assets and liabilities denominated in foreign currency at the year-end rates are recognized in the consolidated income statement, unless they are deferred in equity, as occurs with cash flow hedges and net investment in foreign operations hedges.

Assets and liabilities of subsidiaries with a functional currency different from the Company’s reporting currency are translated to U.S. dollars at the exchange rate in force at the closing date of the financial statements. Income and expenses are translated into U.S. dollars using the average annual exchange rate, which does not differ significantly from using the exchange rates of the dates of each transaction. The difference between equity translated at the historical exchange rate and the net financial position that results from translating the assets and liabilities at the closing rate is recorded in equity under the heading “Accumulated currency translation differences”.

Results of companies carried under the equity method are translated at the average annual exchange rate.

2.17. Equity

The Company has recyclable balances in its equity, corresponding mainly to hedge reserves and translation differences arising from currency conversion in the preparation of these consolidated financial statements. These balances have been presented separately in Equity.

Non-controlling interest represents interest from other partners in entities included in these consolidated financial statements which are not fully owned by Atlantica Yield as of the dates presented.

Parent company reserves together with the Share capital represent the Parent’s net investment in the entities included in these consolidated financial statements.

2.18. Provisions and contingencies

Provisions are recognized when:

there is a present obligation, either legal or constructive, as a result of past events;

it is more likely than not that there will be a future outflow of resources to settle the obligation; and

the amount has been reliably estimated.

Provisions are initially measured at the present value of the expected outflows required to settle the obligation and subsequently valued at amortized cost following the effective interest method. The balance of Provisions disclosed in the Notes reflects management’s best estimate of the potential exposure as of the date of preparation of the consolidated financial statements.

Contingent liabilities are possible obligations, existing obligations with low probability of a future outflow of economic resources and existing obligations where the future outflow cannot be reliably estimated. Contingences are not recognized in the consolidated statements of financial position unless they have been acquired in a business combination.

Some companies included in the group have dismantling provisions, which are intended to cover future expenditures related to the dismantlement of the plants and it will be likely to be settled with an outflow of resources in the long term (over 5 years).

Such provisions are accrued when the obligation for dismantling, removing and restoring the site on which the plant is located, is incurred, which is usually during the construction period. The provision is measured in accordance with IAS 37, “Provisions, Contingent Liabilities and Contingent Assets” and is recorded as a liability under the heading “Grants and other liabilities” of the Financial Statements, and as part of the cost of the plant under the heading “Contracted concessional assets.”

2.19. Use of estimates

Some of the accounting policies applied require the application of significant judgment by management to select the appropriate assumptions to determine these estimates. These assumptions and estimates are based on the historical experience, advice from experienced consultants, forecasts and other circumstances and expectations as of the close of the financial period. The assessment is considered in relation to the global economic situation of the industries and regions where the Company operates, taking into account future development of the businesses of the Company. By their nature, these judgments are subject to an inherent degree of uncertainty; therefore, actual results could materially differ from the estimates and assumptions used. In such cases, the carrying values of assets and liabilities are adjusted.

The most critical accounting policies, which reflect significant management estimates and judgment to determine amounts in these consolidated financial statements, are as follows:

Contracted concessional agreements and PPAs.

Impairment of intangible assets and property, plant and equipment.

Assessment of control.

Derivative financial instruments and fair value estimates.

Income taxes and recoverable amount of deferred tax assets.

As of the date of preparation of these consolidated financial statements, no relevant changes in the estimates made are anticipated and, therefore, no significant changes in the value of the assets and liabilities recognized at December 31, 2017, are expected.

Although these estimates and assumptions are being made using all available facts and circumstances, it is possible that future events may require management to amend such estimates and assumptions in future periods. Changes in accounting estimates are recognized prospectively, in accordance with IAS 8, in the consolidated income statement of the year in which the change occurs.

Financial risk management

12 Months Ended

Dec. 31, 2017

Financial risk management [Abstract]

Financial risk management

Note 3.- Financial risk management

Atlantica Yield’s activities are exposed to various financial risks: market risk (including currency risk and interest rate risk), credit risk and liquidity risk. Risk is managed by the Company’s Risk Finance and Compliance Departments, which are responsible for identifying and evaluating financial risks quantifying them by project, region and company, in accordance with mandatory internal management rules. Written internal policies exist for global risk management, as well as for specific areas of risk. In addition, there are official written management regulations regarding key controls and control procedures for each company and the implementation of these controls is monitored through internal audit procedures.

Market risk

The Company is exposed to market risk, such as movement in foreign exchange rates and interest rates. All of these market risks arise in the normal course of business and the Company does not carry out speculative operations. For the purpose of managing these risks, the Company uses a series of interest rate swaps and options, and currency options. None of the derivative contracts signed has an unlimited loss exposure.

Interest rate risk

Interest rate risk arises when the Company’s activities are exposed to changes in interest rates, which arises from financial liabilities at variable interest rates. The main interest rate exposure for the Company relates to the variable interest rate with reference to the Libor and Euribor. To minimize the interest rate risk, the Company primarily uses interest rate swaps and interest rate options (caps), which, in exchange for a fee, offer protection against an increase in interest rates. The Company does not use derivatives for speculative purposes.

As a result, the notional amounts hedged, strikes contracted and maturities, depending on the characteristics of the debt on which the interest rate risk is being hedged, are very diverse, including the following:

Project debt in Euros: the Company hedges between 87% and 100% of the notional amount, maturities until 2030 and average guaranteed interest rates of between 3.20% and 4.87%.

Project debt in U.S. dollars: the Company hedges between 70% and 100% of the notional amount, including maturities until 2032 and average guaranteed interest rates of between 2.32% and 5.27%.

In connection with the interest rate derivative positions of the Company, the most significant impacts on these consolidated financial statements are derived from the changes in EURIBOR or LIBOR, which represent the reference interest rate for the majority of the debt of the Company. In the event that Euribor and Libor had risen by 25 basis points as of December 31, 2017, with the rest of the variables remaining constant, the effect in the consolidated income statement would have been a loss of $228 thousand (a loss of $2,563 thousand in 2016 and a loss of $1,795 thousand in 2015) and an increase in hedging reserves of $37,767 thousand ($37,290 thousand in 2016 and $41,702 thousand in 2015). The increase in hedging reserves would be mainly due to an increase in the fair value of interest rate swaps designated as hedges.

A breakdown of the interest rates derivatives as of December 31, 2017 and 2016, is provided in Note 9.

Currency risk

The main cash flows in the entities included in these consolidated financial statements are cash collections arising from long-term contracts with clients and debt payments arising from project finance repayment. Given that financing of the projects is always closed in the same currency in which the contract with client is signed, a natural hedge exists for the main operations of the Company.

In addition, the Company policy is to contract currency options with leading financial institutions, which guarantee a minimum Euro-U.S. dollar exchange rate on the net distributions expected from Spanish solar assets. The net Euro exposure is 100% covered for the coming 12 months and 75% for the following 12 months on a rolling basis.

Credit risk

The Company considers that it has a limited credit risk with clients as revenues derive from power purchase agreements with electric utilities and state-owned entities. The Company has investment grade offtakers in all the assets except for Quadra 1&2, ATN2, Skikda and Honaine, which represent a low percentage of the cash available for distribution on a run-rate basis. In the case of Kaxu, the offtaker has a counter-guarantee from the Republic of South Africa.

Liquidity risk

Atlantica Yield’s liquidity and financing policy is intended to ensure that the Company maintains sufficient funds to meet our financial obligations as they fall due.

Project finance borrowing permits the Company to finance the project through project debt and thereby insulate the rest of its assets from such credit exposure. The Company incurs in project-finance debt on a project-by-project basis.

The repayment profile of each project is established on the basis of the projected cash flow generation of the business. This ensures that sufficient financing is available to meet deadlines and maturities, which mitigates the liquidity risk significantly.

Financial information by segment

12 Months Ended

Dec. 31, 2017

Financial information by segment [Abstract]

Financial information by segment

Note 4.- Financial information by segment

Atlantica Yield’s segment structure reflects how management currently makes financial decisions and allocates resources. Its operating and reportable segments are based on the following geographies where the contracted concessional assets are located:

North America

South America

EMEA

Based on the type of business, as of December 31, 2017 the Company had the following business sectors:

Renewable energy: Renewable energy assets include two solar plants in the United States, Solana and Mojave, each with a gross capacity of 280 MW and located in Arizona and California, respectively. The Company owns eight solar platforms in Spain: Solacor 1 and 2 with a gross capacity of 100 MW, PS10 and PS20 with a gross capacity of 31 MW, Solaben 2 and 3 with a gross capacity of 100 MW, Helioenergy 1 and 2 with a gross capacity of 100 MW, Helios 1 and 2 with a gross capacity of 100 MW, Solnova 1, 3 and 4 with a gross capacity of 150 MW, Solaben 1 and 6 with a gross capacity of 100 MW and Seville PV with a gross capacity of 1 MW. The Company also owns a solar plant in South Africa, Kaxu with a gross capacity of 100 MW. Additionally, the Company owns two wind farms in Uruguay, Palmatir and Cadonal, with a gross capacity of 50 MW each.

Efficient natural gas: The Company´s sole efficient natural gas asset is ACT, a 300 MW cogeneration plant in Mexico, which is party to a 20-year take-or-pay contract with Pemex for the sale of electric power and steam.

Electric transmission lines: Electric transmission assets include (i) three lines in Peru, ATN, ATS and ATN2, spanning a total of 1,012 miles; and (ii) three lines in Chile, Quadra 1, Quadra 2 and Palmucho, spanning a total of 87 miles.

Water: Water assets include a minority interest in two desalination plants in Algeria, Honaine and Skikda with an aggregate capacity of 10.5 M ft³ per day.

Atlantica Yield’s Chief Operating Decision Maker (CODM) assesses the performance and assignment of resources according to the identified operating segments. The CODM considers the revenues as a measure of the business activity and the Further Adjusted EBITDA as a measure of the performance of each segment. Further Adjusted EBITDA is calculated as profit/(loss) for the period attributable to the parent company, after adding back loss/(profit) attributable to non-controlling interests from continued operations, income tax, share of profit/(loss) of associates carried under the equity method, finance expense net, depreciation, amortization and impairment charges of entities included in these consolidated financial statements, and dividends received from the preferred equity investment in ACBH. Further adjusted EBITDA for 2016 and 2017 includes compensation received from Abengoa in lieu of ACBH dividends.

In order to assess performance of the business, the CODM receives reports of each reportable segment using revenues and Further Adjusted EBITDA. Net interest expense evolution is assessed on a consolidated basis. Financial expense and amortization are not taken into consideration by the CODM for the allocation of resources.

In the years ended December 31, 2017 and December 31, 2016, Atlantica Yield had three customers with revenues representing more than 10% of the total revenues, i.e., two in the renewable energy and one in the efficient natural gas business sectors.

The following tables show Revenues and Further Adjusted EBITDA by operating segments and business sectors for the years 2017, 2016 and 2015:

	Revenue									Further Adjusted EBITDA
	For the year ended December 31,									For the year ended December 31,
Geography	2017			2016			2015			2017			2016			2015
North America		$	332,705		$	337,061		$	328,139		$	282,328		$	284,691		$	279,559
South America			120,797			118,764			112,480			108,766			124,599			110,905
EMEA			554,879			515,972			350,262			388,216			354,020			233,754
Total		$	1,008,381		$	971,797		$	790,881		$	779,310		$	763,310		$	624,218

	Revenue									Further Adjusted EBITDA
	For the year ended December 31,									For the year ended December 31,
Business sectors	2017			2016			2015			2017			2016			2015
Renewable energy		$	767,226		$	724,325		$	543,012		$	569,193		$	538,427		$	413,933
Efficient natural gas			119,784			128,046			138,717			106,140			106,492			107,671
Electric transmission lines			95,096			95,137			86,393			87,695			104,795			89,047
Water			26,275			24,288			22,759			16,282			13,596			13,567
Total		$	1,008,381		$	971,797		$	790,881		$	779,310		$	763,310		$	624,218

The reconciliation of segment Further Adjusted EBITDA with the profit/(loss) attributable to the parent company is as follows:

	For the year ended December 31,
	2017			2016			2015
Loss attributable to the Company	$	(111,804	)	$	(4,855	)	$	(209,005	)
Profit attributable to non-controlling interests		6,917			6,522			10,819
Income tax		119,837			1,666			23,790
Share of profits/(losses) of associates		(5,351	)		(6,646	)		(7,844	)
Dividend from exchangeable preferred equity investment in ACBH (Note 21)		10,383			27,948			18,400
Financial expense, net		448,368			405,750			526,758
Depreciation, amortization, and impairment charges		310,960			332,925			261,301
Total segment Further Adjusted EBITDA	$	779,310		$	763,310		$	624,219

The assets and liabilities by operating segments (and business sector) at the end of 2017 and 2016 are as follows:

Assets and liabilities by geography as of December 31, 2017:

	North America		South America		EMEA		Balance as of December 31, 2017
Assets allocated
Contracted concessional assets		3,770,169		1,100,778		4,213,323		9,084,270
Investments carried under the equity method		-		-		55,784		55,784
Current financial investments		116,451		59,831		31,263		207,545
Cash and cash equivalents (project companies)		149,236		42,548		329,078		520,862
Subtotal allocated		4,035,856		1,203,157		4,629,448		9,868,461
Unallocated assets
Other non-current assets								210,378
Other current assets (including cash and cash equivalents at holding company level)								413,500
Subtotal unallocated								623,878
Total assets								10,492,339

	North America		South America		EMEA		Balance as of December 31, 2017
Liabilities allocated
Long-term and short-term project debt		1,821,102		876,063		2,778,043		5,475,208
Grants and other liabilities		1,593,048		810		42,202		1,636,060
Subtotal allocated		3,414,150		876,873		2,820,245		7,111,268
Unallocated liabilities
Long-term and short-term corporate debt								643,083
Other non-current liabilities								657,345
Other current liabilities								185,190
Subtotal unallocated								1,485,618
Total liabilities								8,596,886
Equity unallocated								1,895,453
Total liabilities and equity unallocated								3,381,071
Total liabilities and equity								10,492,339

Assets and liabilities by geography as of December 31, 2016:

	North America		South America		EMEA		Balance as of December 31, 2016
Assets allocated
Contracted concessional assets		3,920,106		1,144,712		3,859,454		8,924,272
Investments carried under the equity method		-		-		55,009		55,009
Current financial investments		136,665		62,215		29,158		228,038
Cash and cash equivalents (project companies)		185,970		40,015		246,671		472,656
Subtotal allocated		4,242,741		1,246,942		4,190,291		9,679,975
Unallocated assets
Other non-current assets								272,664
Other current assets (including cash and cash equivalents at holding company level)								345,160
Subtotal unallocated								617,824
Total assets								10,297,799

	North America		South America		EMEA		Balance as of December 31, 2016
Liabilities allocated
Long-term and short-term project debt		1,870,861		895,316		2,564,290		5,330,467
Grants and other liabilities		1,575,303		1,512		35,230		1,612,045
Subtotal allocated		3,446,164		896,828		2,599,520		6,942,512
Unallocated liabilities
Long-term and short-term corporate debt								668,201
Other non-current liabilities								546,053
Other current liabilities								181,922
Subtotal unallocated								1,396,176
Total liabilities								8,338,688
Equity unallocated								1,959,111
Total liabilities and equity unallocated								3,355,287
Total liabilities and equity								10,297,799

Assets and liabilities by business sectors as of December 31, 2017:

	Renewable energy		Efficient natural gas		Electric transmission lines		Water		Balance as of December 31, 2017
Assets allocated
Contracted concessional assets		7,436,362		660,387		897,269		90,252		9,084,270
Investments carried under the equity method		12,419		-		-		43,365		55,784
Current financial investments		17,249		116,430		59,289		14,577		207,545
Cash and cash equivalents (project companies)		452,792		39,064		15,325		13,681		520,862
Subtotal allocated		7,918,822		815,881		971,883		161,875		9,868,461
Unallocated assets
Other non-current assets										210,378
Other current assets (including cash and cash equivalents at holding company level)										413,500
Subtotal unallocated										623,878
Total assets										10,492,339

	Renewable energy		Efficient natural gas		Electric transmission lines		Water		Balance as of December 31, 2017
Liabilities allocated
Long-term and short-term project debt		4,162,596		579,173		698,346		35,093		5,475,208
Grants and other liabilities		1,635,508		552		-		-		1,636,060
Subtotal allocated		5,798,104		579,725		698,346		35,093		7,111,268
Unallocated liabilities
Long-term and short-term corporate debt										643,083
Other non-current liabilities										657,345
Other current liabilities										185,190
Subtotal unallocated										1,485,618
Total liabilities										8,596,886
Equity unallocated										1,895,453
Total liabilities and equity unallocated										3,381,071
Total liabilities and equity										10,492,339

Assets and liabilities by business sectors as of December 31, 2016:

	Renewable energy		Efficient natural gas		Electric transmission lines		Water		Balance as of December 31, 2016
Assets allocated
Contracted concessional assets		7,255,308		646,927		929,005		93,032		8,924,272
Investments carried under the equity method		12,953		-		-		42,056		55,009
Current financial investments		13,661		136,644		62,215		15,518		228,038
Cash and cash equivalents (project companies)		420,215		30,295		11,357		10,789		472,656
Subtotal allocated		7,702,137		813,866		1,002,577		161,395		9,679,975
Unallocated assets
Other non-current assets										272,664
Other current assets (including cash and cash equivalents at holding company level)										345,160
Subtotal unallocated										617,824
Total assets										10,297,799

	Renewable energy		Efficient natural gas		Electric transmission lines		Water		Balance as of December 31, 2016
Liabilities allocated
Long-term and short-term project debt		3,979,096		598,256		711,517		41,598		5,330,467
Grants and other liabilities		1,611,067		239		739		-		1,612,045
Subtotal allocated		5,590,163		598,495		712,256		41,598		6,942,512
Unallocated liabilities
Long-term and short-term corporate debt										668,201
Other non-current liabilities										546,053
Other current liabilities										181,922
Subtotal unallocated										1,396,176
Total liabilities										8,338,688
Equity unallocated										1,959,111
Total liabilities and equity unallocated										3,355,287
Total liabilities and equity										10,297,799

The amount of depreciation, amortization and impairment charges recognized for the years ended December 31, 2017, 2016 and 2015 are as follows:

	For the year ended December 31,
Depreciation, amortization and impairment by geography	2017			2016			2015
North America		(123,726	)		(129,478	)		(129,091	)
South America		(40,880	)		(62,387	)		(41,274	)
EMEA		(146,354	)		(141,060	)		(90,936	)
Total		(310,960	)		(332,925	)		(261,301	)

	For the year ended December 31,
Depreciation, amortization and impairment by business sectors	2017			2016			2015
Renewable energy		(282,376	)		(304,235	)		(232,699	)
Electric transmission lines		(28,584	)		(28,690	)		(28,602	)
Total		(310,960	)		(332,925	)		(261,301	)

Changes in the scope of the consolidated financial statements	12 Months Ended
	Dec. 31, 2017
Changes in the scope of the consolidated financial statements [Abstract]
Changes in the scope of the consolidated financial statements	Note 5.- Changes in the scope of the consolidated financial statements For the year ended December 31, 2017 There is no change in the scope of the consolidated financial statement in the year 2017. For the year ended December 31, 2016 On January 7, 2016, the Company closed the acquisition of a 13% stake in Solacor 1/2 from JGC, which reduced JGC´s ownership in Solacor 1/2 to 13%. The total purchase price for these assets amounted to $19,923 thousand. The difference between the amount of Non-Controlling interest representing the 13% interest held by JGC accounted for in the consolidated accounts at the purchase date, and the purchase price has been recorded in equity in these consolidated financial statements, pursuant to IFRS 10, Consolidated Financial Statements. On August 3, 2016, the Company completed the acquisition of an 80% stake in Seville PV. Total purchase price paid for this asset amounted to $3,214 thousand. The purchase has been accounted for in the consolidated accounts of Atlantica Yield, in accordance with IFRS 3, Business Combinations.

Contracted concessional assets

12 Months Ended

Dec. 31, 2017

Contracted concessional assets [Abstract]

Contracted concessional assets

Note 6.- Contracted concessional assets

Contracted concessional assets include fixed assets financed through project debt, related to service concession arrangements recorded in accordance with IFRIC 12, except for Palmucho, which is recorded in accordance with IAS 17, and PS10, PS20 and Seville PV which are recorded as property plant and equipment in accordance with IAS 16. Concessional assets recorded in accordance with IFRIC 12 are either intangible of financial assets. As of December 31, 2017, contracted concessional financial assets amount to $936,004 thousand ($928,720 thousand as of December 31, 2016).

For further details on the application of IFRIC 12 to projects, see Appendix III.

The following table shows the movements of contracted concessional assets included in the heading “Contracted Concessional assets” for 2017:

Cost

Total as of January 1, 2017	10,067,596
Additions	15,426
Subtractions	(42,500	)
Translation differences	593,247
Total as of December 31, 2017	10,633,769

Accumulated amortization

Total as of January 1, 2017	(1,143,324	)
Additions	(309,846	)
Translation differences	(96,329	)
Total accum. amort. as of December 31, 2017	(1,549,499	)
Net balance at December 31, 2017	9,084,270

During 2017 contracted concessional assets increased primarily due to the effect of appreciation of the Euro against the U.S. dollar for the year ended December 31, 2017 compared to the year ended December 31, 2016, this effect has been partially compensated by the amortization charge for the year.

The decrease relates to the indemnity received from Abengoa by Solana in December 2017 further to Abengoa´s obligation as EPC Contractor (see Note 10).

No losses from impairment of contracted concessional assets were recorded during the year ended December 31, 2017.

The Company identified a triggering event of impairment for Solana as a result of the generation of the plant having been lower than expected during 2017 related to an incident with electric transformers which took place in July 2017. This project is within the Renewable energy sector and North America geography. The Company therefore performed an impairment test as of December 31, 2017, which resulted in the recoverable amount (value in use) exceeding the carrying amount of the asset by 7%. To determine the value in use of the asset, a specific discount rate has been used in each year considering changes in the debt/equity leverage ratio over the useful life of this project, resulting in the use of a range of discount rates between 4.7% and 5.0%.

An adverse change in the key assumptions which are individually used for the valuation would not lead to future impairment recognition; neither in case of a 5% decrease in generation over the entire remaining useful life (PPA) of the project nor in case of an increase of 50 basis points in the discount rate.

The following table shows the movements of contracted concessional assets included in the heading “Contracted Concessional assets” for 2016:

Cost

Total as of January 1, 2016	10,126,023
Additions	6,346
Translation differences	(68,199	)
Change in the scope of the consolidated financial statements	5,876
Reclassification and other movements	(2,450	)

Total as of December 31, 2016	10,067,596

Accumulated amortization

Total as of January 1, 2016	(825,126	)
Additions	(332,925	)
Change in the scope of the consolidated financial statements	(2,381	)
Translation differences	17,108
Total accum. amort. as of December 31, 2016	(1,143,324	)
Net balance at December 31, 2016	8,924,272

During 2016 contracted concessional assets decreased primarily due to the amortization charge for the year.

Considering the low level of wind resources recorded since COD in Palmatir and Cadonal projects and the uncertainty around such level in the future, the Company identified a triggering event of impairment during the year 2016 in compliance with IAS 36, Impairment of Assets. As a result, impairment tests have been performed resulting in the recording of an impairment loss of $17,229 thousand and $3,101 thousand for the Cadonal and Palmatir projects, respectively, as of December 31, 2016.

The impairment has been recorded within the line “Depreciation, amortization and impairment charges” of the consolidated income statement, decreasing the amount of “Contracted concessional assets” pertaining to the Renewable energy sector and South America geography. The recoverable amount considered is the value in use and amounts to $91,795 thousand and $123,912 thousand for Cadonal and Palmatir, respectively, as of December 31, 2016. A specific discount rate has been used in each year considering changes in the debt/equity leverage ratio over the useful life of this project, resulting in the use of a range of discount rates between 6.7% and 7.0% for both projects.

An adverse change in the key assumptions which are individually used for the valuation could lead to future impairment recognition; especially, a 5% decrease in generation over the entire remaining useful life (PPA) of the project would generate an additional impairment of approximately $5 million for Cadonal and $7 million for Palmatir. An increase of 50 basis points in the discount rate would lead to an additional impairment of approximately $3 million for Cadonal and $4 million for Palmatir.

In addition, the Company identified a triggering event of impairment for Solana as a result of the generation of the plant having been lower than expected during its first years of operation. This project pertains to the Renewable energy sector and North America geography. The Company therefore performed an impairment test as of December 31, 2016, which resulted in the recoverable amount (value in use) exceeding the carrying amount of the asset by 3%. To determine the value in use of the asset, a specific discount rate has been used in each year considering changes in the debt/equity leverage ratio over the useful life of this project, resulting in the use of a range of discount rates between 4.1% and 5.1%.

An adverse change in the key assumptions which are individually used for the valuation could lead to future impairment recognition; especially, a 5% decrease in generation over the entire remaining useful life (PPA) of the project would generate an impairment of approximately $40 million. An increase of 50 basis points in the discount rate would lead to an impairment of approximately $30 million.

Investments carried under the equity method

12 Months Ended

Dec. 31, 2017

Investments carried under the equity method [Abstract]

Investments carried under the equity method

Note 7.- Investments carried under the equity method

The table below shows the breakdown and the movement of the investments held in associates for 2017 and 2016:

Investments in associates	2017			2016
Initial balance		55,009			56,181
Share of (loss)/profit		5,351			6,646
Dividend distribution		(2,454	)		(3,954	)
Equity distribution		(549	)		(3,099	)
Currency translation differences		(1,573	)		(765	)
Final balance		55,784			55,009

There are no significant movement of the investments held in associates during the year 2017.

The tables below show a breakdown of stand-alone amounts of assets, revenues and profit and loss as well as other information of interest for the years 2017 and 2016 for the associated companies:

Company	% Shares		Non- current assets		Current assets		Non- current liabilities		Current liabilities		Revenue		Operating profit/ (loss)			Net profit/ (loss)			Investment under the equity method
Evacuación Valdecaballeros, S.L.		57.16		21,306		841		373		451		298		(708	)		(730	)		9,175
Myah Bahr Honaine, S.P.A.(*)		25.50		195,275		64,114		91,205		12,649		46,767		28,468			24,464			43,365
Pectonex, R.F. Proprietary Limited		50.00		3,904		-		-		2		-		(206	)		(206	)		3,244
Evacuación Villanueva del Rey, S.L		40.02		3,526		53		2,265		190		-		37			-			-
As of December 31, 2017				240,011		65,008		93,843		13,292		47,065		27,591			23,528			55,784

Company	% Shares		Non- current assets		Current assets		Non- current liabilities		Current liabilities		Revenue		Operating profit/ (loss)			Net profit/ (loss)			Investment under the equity method
Evacuación Valdecaballeros, S.L.		57.16		19,283		931		306		532		537		(545	)		(565	)		9,528
Myah Bahr Honaine, S.P.A.(*)		25.50		202,150		67,120		104,704		14,158		52,770		34,247			29,990			42,056
Pectonex, R.F. Proprietary Limited		50.00		3,730		-		-		1		-		(187	)		(187	)		3,425
Evacuación Villanueva del Rey, S.L		40.02		3,251		17		2,118		142		-		31			-			-
As of December 31, 2016				228,684		68,068		107,128		14,833		53,307		33,546			29,238			55,009

The Company has no control over Evacuación Valdecaballeros, S.L. as all relevant decisions of this company require the approval of a minimum of shareholders accounting for more than 75% of the shares.

None of the associated companies referred to above is a listed company.

(*) Myah Bahr Honaine, S.P.A., the project entity, is 51% owned by Geida Tlemcen, S.L. which is accounted for using the equity method in these consolidated financial statements. Share of profit of Myah Bahr Honaine S.P.A. included in these consolidated financial statements amounts to $6,238 thousand in 2017 and $7,647 thousand in 2016.

Financial instruments by category

12 Months Ended

Dec. 31, 2017

Financial instruments by category [Abstract]

Financial instruments by category

Note 8.- Financial instruments by category

Financial instruments are primarily deposits, derivatives, trade and other receivables and loans. Financial instruments by category (current and non-current), reconciled with the statement of financial position as of December 31, 2017 and 2016 are as follows:

	Notes		Loans and receivables / payables		Available for sale financial assets		Hedging derivatives		Balance as of December 31, 2017
Derivative assets		9		-		-		8,230		8,230
Investment in Ten West Link				2,088		-		-		2,088
Abengoa debt and Equity instruments				-		1,715		-		1,715
Other financial investments				243,347		-		-		243,347
Clients and other receivables		11		244,449		-		-		244,449
Cash and cash equivalents		12		669,387		-		-		669,387
Total financial assets				1,159,271		1,715		8,230		1,169,216

Corporate debt	14	643,083	-	-	643,083
Project debt	15	5,475,208	-	-	5,475,208
Related parties – non-current	10	141,031	-	-	141,031
Trade and other current liabilities	17	155,144	-	-	155,144
Derivative liabilities	9	-	-	329,731	329,731
Total financial liabilities		6,414,466	-	329,731	6,744,197

	Notes		Loans and receivables / payables		Available for sale financial assets		Hedging derivatives		Balance as of December 31, 2016
Derivative assets		9		-		-		3,822		3,822
Preferred equity in ACBH				-		30,488		-		30,488
Other financial investments				263,501		-		-		263,501
Clients and other receivables		11		207,621		-		-		207,621
Cash and cash equivalents		12		594,811		-		-		594,811
Total financial assets				1,065,933		30,488		3,822		1,100,243

Corporate debt	14	668,201	-	-	668,201
Project debt	15	5,330,467	-	-	5,330,467
Related parties – non-current	10	101,750	-	-	101,750
Trade and other current liabilities	17	160,505	-	-	160,505
Derivative liabilities	9	-	-	349,266	349,266
Total financial liabilities		6,260,923	-	349,266	6,610,189

Further to the completion of a series of conditions precedent that made Abengoa´s restructuring effective as of March 31, 2017, the guarantee provided by Abengoa regarding the preferred equity investment in ACBH, which supported the fair value of this instrument of $30.5 million as of December 31, 2016, was canceled, which reduced the fair value of this instrument to nil. In exchange for the guarantee provided by Abengoa being canceled, the Company received a certain amount of equity in Abengoa, and Corporate tradable bonds issued by Abengoa and subject to a 5.5-year period stay (extendable to a 2 additional years subject further to the senior old money creditors´consent) and with a 1.5% annual interest rate (0.25% cash, 1.25% PIK).

Further to the restructuring agreement of Abengoa being made effective, the Company was assigned an amount of New Money 1 Tradable Notes of $44.5 million in exchange for contributing $43.6 million of cash. As a result of this contribution, the corporate tradable bonds detailed above are ranked as senior debt. The Company sold all the New Money 1 Tradable Notes it was assigned during the month of April 2017 for $44.9 million.

New Money 1 Tradable Notes assigned to Atlantica Yield, Corporate tradable bonds and shares in Abengoa received, together are further referred as “Abengoa Debt and Equity Instruments”. These are all available for sale financial assets, of which major part has been sold during the second, third and fourth quarter of 2017. The fair value of the remaining portion as of December 31, 2017 amounts to $1.7 million, and is classified as current financial investments.

Derecognition of the fair value assigned to the ACBH preferred equity investment and recognition of the Abengoa Debt and Equity Instruments resulted in a loss of $5.8 million. The sale of these instruments resulted in a profit of $6.5 million. Both impacts are accounted for in these consolidated financial statements for the year ended December 31, 2017 as Other net financial income and expenses (see Note 21).

Prior to Abengoa´s restructuring agreement being made effective, Abengoa acknowledged that it failed to fulfill its obligations under the agreements related to the preferred equity investment in ACBH and, as a result, Atlantica Yield is the legal owner of the dividends amounting to $10.4 million declared on February 24, 2017, that the Company retained from Abengoa. Upon receipt of Abengoa Debt and Equity Instruments, the Company waived its rights under the guarantee provided by Abengoa related to the ACBH agreements, including its right to retain the dividends payable to Abengoa.

Other financial investments include primarily the short-term portion of contracted concessional assets (see Note 6).

Investment in Ten West Link as of December 31, 201 is a $2.1 million investment, which was made by the Company accounting for a 12.5% interests in a 114-mile transmission line in the U.S.

As of December 31, 2017 and 2016, all the financial instruments measured at fair value have been classified as Level 2, except for the Abengoa Debt and Equity Instruments received further to the implementation of Abengoa´s restructuring agreement on March 31st 2017. The unsold portion as of December 31st 2017 is classified as Level 1.

Derivative financial instruments

12 Months Ended

Dec. 31, 2017

Derivative financial instruments [Abstract]

Derivative financial instruments

Note 9.- Derivative financial instruments

The breakdowns of the fair value amount of the derivative financial instruments as of December 31, 2017 and 2016 are as follows:

Balance as of December 31, 2017

Balance as of December 31, 2016

Assets

Liabilities

Assets

Liabilities

Derivatives - cash flow hedge

8,230

329,731

3,822

349,266

The derivatives are primarily interest rate cash-flow hedges. All are classified as non-current assets or non-current liabilities, as they hedge long-term financing agreements.

On May 12, 2015, the Company entered into a currency swap agreement with Abengoa which provided for a fixed exchange rate for the cash available for distribution from the Company’s Spanish assets. The distributions from the Spanish assets are paid in euros and the currency swap agreement provided for a fixed exchange rate at which euros will be converted into U.S. dollars. The currency swap agreement had a five-year term, and was valued by comparing the contracted exchange rate and the future exchange rate in the valuation scenario at the maturities dates. The instrument was valued by calculating the cash flow that would be obtained or paid by theoretically closing out the position and then discounting that amount. The Company terminated this agreement with Abengoa in October 2017 (see Note 21).

Additionally, the Company signed during the year ended December 31, 2017, currency options with leading international financial institutions, which guarantee a minimum Euro-U.S. dollar exchange rates for the distributions expected from Spanish solar assets made in euros during the years 2017, 2018 and part of 2019.

As stated in Note 3 to these consolidated financial statements, the general policy is to hedge variable interest rates of financing agreements purchasing call options (caps) in exchange of a premium to fix the maximum interest rate cost and contracting floating to fixed interest rate swaps.

As a result, the notional amounts hedged, strikes contracted and maturities, depending on the characteristics of the debt on which the interest rate risk is being hedged, can be diverse:

·	Project debt in Euros: the Company hedges between 87% and 100% of the notional amount, maturities until 2030 and average guaranteed interest rates of between 3.20% and 4.87%.

·	Project debt in U.S. dollars: the Company hedges between 70% and 100% of the notional amount, including maturities until 2032 and average guaranteed interest rates of between 2.32% and 5.27%.

The table below shows a breakdown of the maturities of notional amounts of derivatives designated as cash flow hedges as of December 31, 2017 and 2016.

Notionals	Balance as of December 31, 2017				Balance as of December 31, 2016
	Cap		Swap		Cap		Swap
Up to 1 year		42,324		139,939		24,261		75,837
Between 1 and 2 years		45,422		94,285		25,934		199,832
Between 2 and 3 years		48,215		103,536		27,880		83,897
Subsequent years		620,378		1,893,850		400,239		1,500,789
Total	$	756,339	$	2,231,611	$	478,314	$	1,860,355

The table below shows a breakdown of the maturity of the fair values of derivatives designated as cash flow hedges as of December 31, 2017 and 2016. The net position of the fair value of caps and swaps for each year end reconciles with the net position of derivative assets and derivative liabilities in the consolidated statement of financial position:

Fair value	Balance as of December 31, 2017					Balance as of December 31, 2016
	Cap		Swap			Cap		Swap
Up to 1 year		347		(13,224	)		250		(12,383	)
Between 1 and 2 years		978		(14,378	)		262		(14,927	)
Between 2 and 3 years		396		(15,923	)		275		(13,957	)
Subsequent years		6,509		(286,206	)		3,035		(307,999	)
Total	$	8,230		(329,731	)	$	3,822		(349,266	)

During 2017, fair value of derivatives increased mainly due to an increase in the fair value of interest rate cash-flow hedges resulting from the increase in future interest rates.

The net amount of the fair value of interest rate derivatives designated as cash flow hedges transferred to the consolidated income statement is a loss of $70,953 thousand (loss of $72,774 thousand in 2016 and a loss of $55,841 thousand in 2015). Additionally, the net amount of the time value component of the cash flow derivatives fair value recognized in the consolidated income statement for the year 2017, 2016 and 2015 has been a loss of $860 thousand, a gain of $1,694 thousand and a gain of $4,234 thousand respectively.

The after-tax result accumulated in equity in connection with derivatives designated as cash flow hedges at the years ended December 31, 2017 and 2016, amount to a $80,968 thousand gain and a $52,797 thousand gain respectively.

Related parties

12 Months Ended

Dec. 31, 2017

Related parties [Abstract]

Related parties

Note 10.- Related parties

During the normal course of business, the Company has historically conducted operations with related parties consisting mainly of Abengoa´s subsidiaries and non-controlling interests. The transactions were completed at market rates.

Details of balances with related parties as of December 31, 2017 and 2016 are as follows:

	Balance as of December 31,
	2017		2016

Credit receivables (current)		11,567		12,031
Total current receivables with related parties		11,567		12,031

Credit receivables (non-current)		2,108		30,505
Total non-current receivables with related parties		2,108		30,505

Trade payables (current)		63,409		61,338
Total current payables with related parties		63,409		61,338

Credit payables (non-current)		141,031		101,750
Total non-current payables with related parties		141,031		101,750

Receivables from related parties as of December 31, 2017 include the remaining portion of Abengoa Debt and Equity Instruments received further to the implementation of Abengoa´s restructuring agreement, pending to be sold. These instruments are accounted for at fair value for $1,715 thousand as of December 31, 2017 and classified as current (see Note 8).

As of December 31, 2016, receivables with related parties primarily corresponded to the preferred equity investment in ACBH for a total amount of $30,488 thousand, classified as non-current (see Note 8).

Trade payables (current) primarily relate to payables for Operation and Maintenance services. Credit payables (non-current) primarily relate to payables of projects companies with partners accounted for as non-controlling interests in these consolidated financial statements.

The transactions carried out by entities included in these consolidated financial statements with related parties not included in the consolidation perimeter of Atlantica Yield, primarily with Abengoa and with subsidiaries of Abengoa, during the twelve-month periods ended December 31, 2017, 2016 and 2015 have been as follows:

	For the year ended December 31,
	2017			2016			2015
Sales		-			-			44,260
Services rendered		3,495			1,220			523
Services received		(114,416	)		(115,779	)		(106,737	)
Financial income		74			60			1,466
Financial expenses		(1,154	)		(2,460	)		(1,968	)

Services received primarily include operation and maintenance services received by some assets. Until December 2015, sales related to sale of energy by Spanish Solar plants were sometimes made through an Abengoa company acting as an agent for the plant. This service is not provided anymore by Abengoa since then.

The figures detailed in the table above do not include the following financial income recorded in these consolidated financial statements for the year ended December 31, 2017: compensation received from Abengoa in lieu of dividends from ACBH for $10.4 million resulting from the agreement signed with Abengoa in the third quarter of 2016 (see Note 8). As of December 31, 2016, the figures do not include the compensation received from Abengoa in lieu of dividends from ACBH for $28.0 million, income for the cancellation of the subordinated debt Solnova Electricidad S.A. owed to Abener for $7.6 million and income of $1.7 million for discounts received from Abengoa for the prepayment of payables.

In addition, Abengoa maintains a number of obligations under EPC, O&M and other contracts, as well as indemnities covering certain potential risks. Additionally, Abengoa represented that further to the accession to the restructuring agreement, Atlantica Yield would not be a guarantor of any obligation of Abengoa with respect to third parties and agreed to indemnify the Company for any penalty claimed by third parties resulting from any breach in such representations. The Company has contingent assets, which have not been recognized as of December 31, 2017, related to the obligations of Abengoa referred above, which result and amounts will depend on the occurrence of uncertain future events.

As explained in Note 1, in November 2017 the Company signed a consent in relation to the Solana and Mojave projects which reduces the minimum ownership required by Abengoa in Atlantica Yield to 16%, subject to certain conditions precedent most of which are beyond the control of the Company, including several payments by Abengoa to Solana before December 2017 and February 2018 (subsequently this date was postponed to May 2018). These payments for a total of $120 million are related to Abengoa’s obligations as EPC contractor in Solana and would be used to repay Solana project debt ($80 million), for current and potential required additional repairs in the plant ($25 million) and for covering other Abengoa obligations ($15 million). Additionally, Abengoa has recognized other obligations with Solana for $6.5 million per semester over 10 years starting in December 2018. In December 2017 Solana received $42.5 million related to Abengoa´s obligation as EPC contractor. The aforementioned amounts are based on the EPC Contract guarantee for liquidated damages considering the average production during the first three years of ramp-up period of the plant which is a service-concession arrangement under IFRIC 12 (intangible asset). For the $42.5 million collected before the end of December 2017, the Company reduced the value of the intangible asset since this amount was a variable consideration. The rest of the amounts to be paid by Abengoa after December 31, 2017 will be accounted for in the same manner, as a reduction of the value of the asset when the different installments are collected. In addition, the amortization of the plant will also be adjusted accordingly.

The Company entered into a Financial Support Agreement on June 13, 2014 under which Abengoa agreed to maintain any guarantees and letters of credit that have been provided by it on behalf of or for the benefit of Atlantica Yield and its affiliates for a period of five years. As of December 2017 the aforementioned guarantees amounted to $31.5 million In the context of that agreement in which Atlantica Yield agreed that it shall use commercially reasonable efforts to replace guarantees, on June 2017, it agreed to replace guarantees amounting to $112 million previously issued by Abengoa. During the third quarter of 2017, the Company issued the aforementioned guarantees and received from Abengoa a payment of €7.8 million for existing debts.

At the date of the initial offering, the Company entered into a series of agreements to receive management, general and administrative services from Abengoa (the “Support Services Agreement” and “Executive Service Agreement”), and corresponding fees were properly accounted for as other operating expenses. The Executive Service Agreement was canceled in February 2015. During the year 2015 and 2016, some employees of Abengoa delivering services under the Support Services Agreement were transferred to entities within the consolidation perimeter of Atlantica Yield and the Support Services Agreement was cancelled. In addition, some external employees were hired. This resulted in the Company increasing its employee benefit expenses as shown in the consolidated income statement for the years 2015, 2016 and 2017.

Clients and other receivable

12 Months Ended

Dec. 31, 2017

Clients and other receivable [Abstract]

Clients and other receivable

Note 11.- Clients and other receivable

Clients and other receivable as of December 31, 2017 and 2016, consist of the following:

	Balance as of December 31,
	2017		2016
Trade receivables		186,728		151,199
Tax receivables		39,607		29,705
Prepayments		6,375		10,261
Other accounts receivable		11,739		16,456
Total		244,449		207,621

As of December 31, 2017 and 2016, the fair value of clients and other accounts receivable does not differ significantly from its carrying value.

Trade receivables in foreign currency as of December 31, 2017 and 2016, are as follows:

	Balance as of December 31,
	2017		2016
Euro		109,165		98,798
Rand		23,792		12,807
Other		7,363		7,151
Total		140,320		118,756

The following table shows the maturity of Trade receivables as of December 31, 2017 and 2016:

	Balance as of December 31,
	2017		2016

Up to 3 months		186,728		151,199
Total		186,728		151,199

Cash and cash equivalents

12 Months Ended

Dec. 31, 2017

Cash and cash equivalents [Abstract]

Cash and cash equivalents

Note 12.- Cash and cash equivalents

The following table shows the detail of Cash and cash equivalents as of December 31, 2017 and 2016:

	Balance as of December 31,
	2017		2016
Cash at bank and on hand		669,387		594,811
Total		669,387		594,811

Cash includes funds held to satisfy the customary requirements of certain non-recourse debt agreements within the Company´s projects amounting to $263 million.

The following breakdown shows the main currencies in which cash and cash equivalent balances are denominated:

	Balance as of December 31,
Currency	2017		2016
U.S. dollar		319,400		343,954
Euro		288,625		196,382
Algerian Dinar		13,628		10,736
South African Rand		40,999		39,689
Others		6,735		4,050
Total		669,387		594,811

Equity

12 Months Ended

Dec. 31, 2017

Equity [Abstract]

Equity

Note 13.- Equity

On June 18, 2014, Atlantica Yield closed its initial public offering issuing 24,850,000 ordinary shares. The shares were sold at a price of $29 per share and as a result the Company raised $720,650 thousand of gross proceeds. The Company recorded $2,485 thousand as Share Capital and $682,810 thousand as Additional Paid in Capital, included in Atlantica Yield reserves as of December 31, 2016, corresponding to the total net proceeds of the offering. The underwriters further purchased 3,727,500 additional shares from the selling shareholder, a subsidiary wholly owned by Abengoa, at the public offering price less fees and commissions to cover over-allotments (“greenshoe”) driving the total proceeds of the offering to $828,748 thousand.

Atlantica Yield’s shares began trading on the NASDAQ Global Select Market under the symbol “ABY” on June 13, 2014. The symbol changed to “AY” on November 11, 2017.

On January 22, 2015, Abengoa closed an underwritten public offering and sale in the United States of 10,580,000 of ordinary shares of the Company for total proceeds of $327,980,000 (or $31 per share). As a result of such offering, Abengoa reduced its stake in the Company from 64.3% to 51.1% of its shares.

On May 14, 2015 Atlantica Yield issued 20,217,260 new shares at $33.14 per share, which was based on a 3% discount versus the May 7, 2015 closing price. Abengoa subscribed for 51% of the newly-issued shares and maintained its previous stake in Atlantica Yield. The proceeds were primarily used by Atlantica Yield to finance asset acquisitions in May and June 2015.

On July 14, 2015, Abengoa sold 2,000,000 shares of Atlantica Yield under Rule 144, reducing its stake to 49.1%.

As of the date hereof, according to Abengoa´s beneficial ownership reporting, Abengoa has delivered an aggregate of 7,595,639 Ordinary Shares to holders that exercised their option to exchange the $279,000 thousand principal amount of exchangeable notes due 2017 issued by Abengoa on March 5, 2015 (the “Exchangeable Notes”) for shares of Atlantica Yield. The Exchangeable Notes are exchangeable, at the option of their holders, for ordinary shares of Atlantica Yield. These operations reduced Abengoa´s stake to 41.47% as of December 31, 2017.

As of December 31, 2017, the share capital of the Company amounts to $10,021,726 represented by 100,217,260 ordinary shares completely subscribed and disbursed with a nominal value of $0.10 each, all in the same class and series. Each share grants one voting right.

Atlantica Yield reserves as of December 31, 2017 are made up of share premium account and distributable reserves.

Retained earnings include results attributable to Atlantica Yield, the impact of the Asset Transfer in equity and the impact of the assets acquisition under the ROFO agreement in equity. The Asset Transfer and the acquisitions under the ROFO agreement were recorded in accordance with the Predecessor accounting principle, given that all these transactions occurred before December 2015, when Abengoa still had control over Atlantica Yield.

Non-controlling interests fully relate to interests held by JGC in Solacor 1 and Solacor 2, by Idae in Seville PV, by Itochu Corporation in Solaben 2 and Solaben 3, by Algerian Energy Company, SPA and Valoriza Agua S.L. in Skikda and by Industrial Development Corporation of South Africa (IDC) and Kaxu Community Trust in Kaxu Solar One (Pty) Ltd.

Additional information of subsidiaries including material Non-controlling interests as of December 31, 2017 and 2016, are disclosed in Appendix IV.

Dividends declared during the year 2017:

On February 27, 2017, the Board of Directors declared a dividend of $0.25 per share corresponding to the four quarter of 2016. The dividend was paid on March 15, 2017. From that amount, the Company retained $10.4 million of the dividend attributable to Abengoa;

On May 15, 2017, the Board of Directors declared a dividend of $0.25 per share corresponding to the first quarter of 2017. The dividend was paid on June 15, 2017;

On August 3, 2017, the Board of Directors declared a dividend of $0.26 per share corresponding to the second quarter of 2017. The dividend was paid on September 15, 2017;

On November 13, 2017, the Board of Directors declared a dividend of $0.29 per share corresponding to the third quarter of 2017. The dividend was paid on December 15, 2017.

In addition, as of December 31, 2017, there was no treasury stock and there have been no transactions with treasury stock during the period then ended.

Corporate debt

12 Months Ended

Dec. 31, 2017

Corporate debt [Abstract]

Grants and other liabilities [Abstract]

Note 14.- Corporate debt

The breakdown of the corporate debt as of December 31, 2017 and 2016 is as follows:

	Balance as of December 31,
Non-current	2017		2016
Credit Facilities with financial entities		320,783		123,804
Notes and Bonds		253,393		252,536
Total Non-Current		574,176		376,340

	Balance as of December 31,
Current	2017		2016
Credit Facilities with financial entities		65,833		289,035
Notes and Bonds		3,074		2,826
Total Current		68,907		291,861

On November 17, 2014, the Company issued the Senior Notes due 2019 in an aggregate principal amount of $255,000 thousand (the “2019 Notes”). The 2019 Notes accrue annual interest of 7.00% payable semi-annually beginning on May 15, 2015 until their maturity date of November 15, 2019.

On December 3, 2014, the Company entered into a credit facility of up to $125,000 thousand with Banco Santander, S.A., Bank of America, N.A., Citigroup Global Markets Limited, HSBC Bank plc and RBC Capital Markets, as joint lead arrangers and joint bookrunners (the “Credit Facility Tranche A”). On December 22, 2014, the Company drew down $125,000 thousand under the Credit Facility Tranche A. Loans accrue interest at a rate per annum equal to: (A) for Eurodollar rate loans, LIBOR plus 2.75% and (B) for base rate loans, the highest of (i) the rate per annum equal to the weighted average of the rates on overnight U.S. Federal funds transactions with members of the U.S. Federal Reserve System arranged by U.S. Federal funds brokers on such day plus 1/2 of 1.00%, (ii) the U.S. prime rate and (iii) LIBOR plus 1.00%, in any case, plus 1.75%. The interest rate on the Credit Facility Tranche A is fully hedged by an interest rate swap contracted with HSBC Bank with maturity date December 24, 2018, resulting in the Company paying a net fixed interest rate of 4.7%. Loans under the Credit Facility Tranche A will mature in December 2018. Loans prepaid by the Company may be reborrowed. The Credit Facility Tranche A is secured by pledges of the shares of the guarantors which the Company owns.

$8,000 thousand of the loans under the Credit Facility Tranche A were partially repaid on September 25, 2017 and for $63,000 thousand on December 27, 2017. As of December 31, 2017, the remaining $54,000 of nominal of the Tranche A has been classified as Current (Non-Current as of December 31,2016), as its maturity is in December 2018.

On June 26, 2015, the Company increased its existing $125 million Credit Facility with a revolver tranche B for an amount of $290,000 thousand (the “Credit Facility Tranche B”). On September 9, 2015, Credit Facility Tranche B was fully drawn down and the proceeds were used for the acquisition of Solaben 1/6. Loans under the Tranche B Credit Facility accrue interest at a rate per annum equal to: (A) for Eurodollar rate loans, LIBOR plus 2.50% and (B) for base rate loans, the highest of (i) the rate per annum equal to the weighted average of the rates on overnight U.S. Federal funds transactions with members of the U.S. Federal Reserve System arranged by U.S. Federal funds brokers on such day plus 1/2 of 1.00%, (ii) the U.S. prime rate and (iii) LIBOR plus 1.00%, in any case, plus 1.50%. Tranche B of the Credit Facility was signed for a total amount of $290,000 thousand with Bank of America, N.A., as global coordinator and documentation agent and Barclays Bank plc and UBS AG, London Branch as joint lead arrangers and joint bookrunners. The Credit Facility Tranche B was classified as Current for $288,317 thousand as of December 31, 2016 (Non-Current as of December 31,2015) as it matured in December 2017. Loans under the Credit facility Tranche B were fully repaid and canceled on February 28, 2017.

On February 10, 2017, the Company issued Senior Notes due 2022, 2023, 2024 (the “Note Issuance Facility”), in an aggregate principal amount of €275,000 thousand. The 2022 to 2024 Notes accrue annual interest, equal to the sum of (i) EURIBOR plus (ii) 4.90%, as determined by the Agent. Interest on the Notes will be payable in cash quarterly in arrears on each interest payment date. The Company will make each interest payment to the holders of record on each interest payment date. The interest rate on the Note Issuance Facility is fully hedged by two interest rate swaps contracted with Jefferies Financial Services, Inc. with effective date March 31, 2017 and maturity date December 31, 2022, resulting in the Company paying a net fixed interest rate of 5.5% on the Note Issuance Facility. Changes in fair value of these interest rate swaps have been recorded in the consolidated income statement. The Note Issuance Facility is a € denominated liability for which the Company applies net investment hedge accounting. When converted to US$ at US$/€ closing exchange rate, it contributes to reduce the impact in translation difference reserves generated in the equity of these consolidated financial statements by the conversion of the net assets of the Spanish solar assets into US$.

On July 20, 2017, the Company signed a credit facility (the “Credit Facility 2017”) for up to €10 million, approximately $11.9 million, which is available in euros or US dollars. Amounts drawn accrue interest at a rate per year equal to EURIBOR plus 2.25% or LIBOR plus 2.25%, depending on the currency. The credit facility has a maturity date of July 20, 2018. As of December 31, 2017, the Company drew down the credit facility in full and used the entire proceeds to prepay a part of the Tranche A of the Credit Facility.

Current corporate debt corresponds to the accrued interest on the Notes, to the outstanding amount of the Tranche A and to the amount of the Credit Facility obtained in July 2017.

The repayment schedule for the Corporate debt, at the end of 2017 is as follows:

	2018		2019		2020		2021		2022		Subsequent years		Total
Credit Facility Tranche A		53,778		-		-		-		-		-		53,778
Note Issuance Facility		107		-		-		-		107,316		213,467		320,890
Credit Facility 2017		11,948		-		-		-		-		-		11,948
2019 Notes		3,074		253,393		-		-		-		-		256,467
Total		68,907		253,393		-		-		107,316		213,467		643,083

The following table details the movement in Corporate debt for the year 2017, split between cash and non-cash items:

		January 1, 2017				Cash Flow				Non-cash changes				December 31, 2017
Corporate debt			668,201				(68,372	)			43,254				643,083

The non-cash changes primarily relates to currency translation differences.

Project debt

12 Months Ended

Dec. 31, 2017

Project debt [Abstract]

Project debt

Note 15.- Project debt

The main purpose of the Company is the long-term ownership and management of contracted concessional assets, such as renewable energy, efficient natural gas, electric transmission line assets and water, which are financed through project debt. This Note shows the project debt linked to the contracted concessional assets included in Note 6 of these consolidated financial statements.

Project debt is generally used to finance contracted assets, exclusively using as guarantee the assets and cash flows of the company or group of companies carrying out the activities financed. In most of the cases, the assets and/or contracts are set up as guarantee to ensure the repayment of the related financing.

Compared with corporate debt, project debt has certain key advantages, including greater leverage period permitted and a longer tenor.

The variations for 2017 and 2016 of project debt have been the following:

	Project debt - long term			Project debt - short term			Total
Balance as of December 31, 2016		4,629,184			701,283			5,330,467
Increases		52,027			304,707			356,734
Decreases		(42,560	)		(509,131	)		(551,691	)
Currency translation differences		316,646			23,052			339,698
Reclassifications		273,620			(273,620	)		-
Balance as of December 31, 2017		5,228,917			246,291			5,475,208

The line “Increases” includes primarily accrued interests for the year.

Main variations in Project debt during the year 2017 are the result of:

Net decrease primarily due to repayment of debt, considering that interests accrued are offset by a similar amount of interests paid during the year. Decrease in long-term debt primarily relates to the partial repayment of Solana debt using the indemnity received from Abengoa in December 2017 for $42.5 million (see Note 10);

A reclassification of the entire debt of Kaxu and Cadonal projects from short term to long term during the year 2017 as a result of the waiver obtained for Kaxu in March 2017 and the completion of certain pending conditions for Cadonal in October 2017. In addition, in 2017, Kaxu’s debt coverage ratio did not reach the minimum threshold due to the technical problems that the plant experienced since the end of 2016. However, the lenders of the project finance agreement granted a waiver to the asset and therefore reclassification of the debt to short-term does not apply in this case.

	Project debt - long term			Project debt - short term			Total
Balance as of December 31, 2015		3,574,464			1,896,205			5,470,669
Increases		36,842			329,434			366,276
Decreases		-			(480,969	)		(480,969	)
Currency translation differences		(64,426	)		38,917			(25,509	)
Reclassifications		1,082,304			(1,082,304	)		-
Balance as of December 31, 2016		4,629,184			701,283			5,330,467

The line “Increases” includes primarily accrued interests for the year.

Main variations in Project debt during the year 2016 were the result of:

-	Net decrease primarily due to repayment of debt; considering that interests accrued were offset by a similar amount of interests paid during the year;

A reclassification of the entire debt of Solana and Mojave projects from short term to long term as of December 31, 2016 considering that as a result of the forbearance signed in December 2016, Abengoa cross-defaults will no longer trigger acceleration remedies in the Solana or Mojave financing agreements.

Debts of Kaxu and Cadonal projects remained classified as short term in accordance with International Accounting Standards 1 (“IAS 1”), “Presentation of Financial Statements” as of December 31, 2016. The waiver of the cross-default provisions related to Abengoa that had been obtained for Cadonal during 2016 was subject to the completion of certain conditions.

The repayment schedule for Project debt in accordance with the financing arrangements, at the end of 2017 is as follows and is consistent with the projected cash flows of the related projects.

2018			2019		2020		2021		2022		Subsequent years		Total
Interest Repayment	Nominal repayment
21,612		224,679		246,471		265,002		280,303		313,559		4,123,582		5,475,208

In 2016, the Company refinanced ATN2 debt. In 2017, the Company did not enter into any new project debt.

Current and non-current loans with credit entities include amounts in foreign currencies for a total of $2,778,043 thousand as of December 31, 2017 ($2,564,291 thousand as of December 31, 2016).

The following table details the movement in Project debt for the year 2017, split between cash and non-cash items:

		January 1, 2017				Cash Flow				Non-cash changes				December 31, 2017
Project debt			5,330,467				(248,472	)			393,212				5,475,208

The non-cash changes primarily relates to currency translation differences.

The equivalent in U.S. dollars of the most significant foreign-currency-denominated debts held by the Company is as follows:

	Balance as of December 31,
Currency	2017		2016
Euro		2,286,771		2,102,985
Algerian Dinar		35,093		41,598
Rand		456,179		419,708
Total		2,778,043		2,564,291

All of the Company’s financing agreements have a carrying amount close to its fair value.

Grants and other liabilities

12 Months Ended

Dec. 31, 2017

Grants and other liabilities

Note 16.- Grants and other liabilities

	Balance as of December 31,
	2017		2016
Grants		1,225,877		1,297,755
Other liabilities		410,183		314,290
Grant and other non-current liabilities		1,636,060		1,612,045

As of December 31, 2017, the amount recorded in Grants corresponds primarily to the ITC Grant awarded by the U.S. Department of the Treasury to Solana and Mojave for a total amount of $771 million ($803 million as of December 31, 2016), which was primarily used to fully repay the Solana and Mojave short-term tranche of the loan with the Federal Financing Bank. The amount recorded in Grants as a liability is progressively recorded as other income over the useful life of the asset.

The remaining balance of the “Grants” account corresponds to loans with interest rates below market rates for Solana and Mojave for a total amount of $452 million ($492 million as of December 31, 2016). Loans with the Federal Financing Bank guaranteed by the Department of Energy for these projects bear interest at a rate below market rates for these types of projects and terms. The difference between proceeds received from these loans and its fair value, is initially recorded as “Grants” in the consolidated statement of financial position, and subsequently recorded in “Other operating income” starting at the entry into operation of the plants. Total amount of income for these two types of grants for Solana and Mojave is $59.8 million and $57.0 million for the year ended December 31, 2017 and 2016, respectively.

Other liabilities mainly relate to the investment from Liberty Interactive Corporation (‘Liberty’) made on October 2, 2013 for an amount of $300 million. The investment was made in class A shares of Arizona Solar Holding, the holding of Solana Solar plant in the United States. Such investment was made in a tax equity partnership which permits the partners to have certain tax benefits such as accelerated depreciation and ITC.

According to the stipulations of IAS 32 and in spite of the fact that the investment of Liberty is in shares, it does not qualify as equity and has been classified as a liability as of December 31, 2017 and 2016. The liability is recorded in Grants and other liabilities for a total amount of $352 million ($263 million as of December 31, 2016) and its current portion is recorded in other current liabilities for the remaining amount (see Note 17). This liability has been initially valued at fair value, calculated as the present value of expected cash-flows during the useful life of the concession, and is then measured at amortized cost in accordance with the effective interest method, considering the most updated expected future cash-flows.

Trade payables and other current liabilities

12 Months Ended

Dec. 31, 2017

Trade payables and other current liabilities [Abstract]

Trade payables and other current liabilities

Note 17.- Trade payables and other current liabilities

Trade payable and other current liabilities as of December 31, 2017 and 2016 are as follows:

	Balance as of December 31,
Item	2017		2016
Trade accounts payables		107,662		121,527
Down payments from clients		6,466		6,153
Suppliers of concessional assets current		236		380
Liberty (see Note 16)		-		21,461
Other accounts payable		40,780		10,984
Total		155,144		160,505

Trade accounts payables mainly relate to the operating and maintenance of the plants.

Nominal values of Trade payable and other current liabilities are considered to approximately equal to fair values and the effect of discounting them is not significant.

Other account payable primarily include subordinated debt of Mojave with Abener Teyma Mojave General Partnership (Abener), a related party, with maturity date on October 2018. The repayment will occur if certain technical conditions are fulfilled.

Income Tax

12 Months Ended

Dec. 31, 2017

Income Tax [Abstract]

Income Tax

Note 18.- Income Tax

All the companies included in the Company file income taxes according to the tax regulations in force in each country on an individual basis or under consolidation tax regulations.

The consolidated income tax has been calculated as an aggregation of income tax expenses/income of each individual company. In order to calculate the taxable income of the consolidated entities individually, the accounting result is adjusted for temporary and permanent differences, recording the corresponding deferred tax assets and liabilities. At each consolidated income statement date, a current tax asset or liability is recorded, representing income taxes currently refundable or payable. Deferred income taxes reflect the net tax effects of temporary differences between the carrying amount of assets and liabilities for financial statement and income tax purposes, as determined under enacted tax laws and rates.

Income tax payable is the result of applying the applicable tax rate in force to each tax-paying entity, in accordance with the tax laws in force in the country in which the entity is registered. Additionally, tax deductions and credits are available to certain entities, primarily relating to inter-company trades and tax treaties between various countries to prevent double taxation.

As of December 31, 2017, and 2016, the analysis of deferred tax assets and deferred tax liabilities is as follows:

Deferred tax assets	Balance as of December 31,
Concept	2017		2016
Net tax credits for operating losses carryforwards		71,219		102,804
Temporary differences derivatives financial instruments		93,719		99,930
Other temporary differences		198		157
Total deferred tax assets		165,136		202,891

Most of the net tax credits for operating losses carryforwards corresponds to Peru, Kaxu and solar plants in Spain as of December 31, 2017.

The balance as of December 31, 2016 also included significant net deferred tax assets for Solana and Mojave, which are now net deferred tax liabilities as of December 31, 2017, due to the following:

In December 2017 a tax reform, the Tax Cuts and Jobs Act, was enacted in the U.S., consisting mainly in a decrease in the corporate tax rate from 35% to 21% effective 1st of January 2018. The Company therefore adjusted the deferred tax assets and liabilities of its U.S. entities using the new enacted corporate tax rate as of December 31, 2017, resulting in a loss of $19 million recorded in the consolidated income statement for the year ended December 31, 2017;

In addition, the U.S. Internal Revenue Code (“IRC”) Section 382 establishes an annual limitation on the use of U.S. Net Operating Losses (“NOLs”) as a result of an ownership change. An “ownership change” would occur if the direct and indirect “5-percent shareholders”, as defined under Section 382 of the IRC, collectively increased their ownership in the Company by more than 50 percentage points over a rolling three-year period. The Company experienced during 2017 an ownership change due to Abengoa´s restructuring and changes in its shareholders´s base. As a result, the U.S. NOLs carryforwards generated through the date of change are subject to an annual limitation under Section 382, which resulted in a derecognition of deferred tax assets previously recognized amounting to $96 million corresponding to an amount of $387 million of NOLs and also taking into consideration the newly enacted corporate tax rate of 21%. This loss has been recorded in the consolidated income statement for the year ended December 31, 2017.

Temporary differences for derivatives financial instruments are mainly due to ACT ($18 million) and solar plants in Spain ($69 million).

In relation to tax loss carryforwards and deductions pending to be used recorded as deferred tax assets, the entities evaluate its recoverability projecting forecasted taxable income for the upcoming years and taking into account their tax planning strategy. Deferred tax liabilities reversals are also considered in these projections, as well as any limitation established by tax regulations in force in each tax jurisdiction.

Deferred tax liabilities	Balance as of December 31,
Concept	2017		2016
Temporary differences tax/book amortization		113,432		28,810
Other temporary differences tax/book value of contracted concessional assets		66,247		61,818
Other temporary differences		6,904		4,409
Total deferred tax liabilities		186,583		95,037

As of December 31, 2017, temporary differences as a result of accelerated tax amortization resulted in a net deferred tax liability position. These are primarily due to Solana and Mojave ($63 million) and solar plants in Spain ($51 million). The increase is primarily due to an impact on the U.S. entities as a result of the tax reform and U.S. Internal Revenue Code Section 382 as previously described.

Other temporary differences tax/book value of contracted concessional assets, which resulted in a net deferred tax liability position relates primarily to ACT in both periods.

The movements in deferred tax assets and liabilities during the years ended December 31, 2017 and 2016 were as follows:

Deferred tax assets	Amount
As of January 1, 2016		191,314
Increase/decrease through the consolidated income statement		16,033
Increase/decrease through other consolidated comprehensive income (equity)		(5,701	)
Other movements		1,245
As of December 31, 2016		202,891

Increase/decrease through the consolidated income statement		(31,421	)
Increase/decrease through other consolidated comprehensive income (equity)		(13,312	)
Other movements		6,978
As of December 31, 2017		165,136

Deferred tax liabilities	Amount
As of January 1, 2016		79,654
Increase/decrease through the consolidated income statement		16,681
Increase/decrease through other consolidated comprehensive income (equity)		(62	)
Other movements		(1,236	)
As of December 31, 2016		95,037

Increase/decrease through the consolidated income statement		86,418
Increase/decrease through other consolidated comprehensive income (equity)		-
Other movements		5,128
As of December 31, 2017		186,583

Details for income tax for the years ended December 31, 2017, 2016 and 2015 are as follows:

	For the twelve-month period ended December 31,
Item	2017			2016			2015
Current tax		(1,998	)		(1,018	)		(2,182	)
Deferred tax		(117,839	)		(648	)		(21,608	)
- relating to the origination and reversal of temporary differences		(98,508	)		(648	)		(22,492	⁾
- relating to changes in tax rates		(19,331	)		-			884
Total income tax benefit/(expense)		(119,837	)		(1,666	)		(23,790	)

The reconciliation between the theoretical income tax resulting from applying an average statutory tax rate to income/(loss) before income tax and the actual income tax expense recognized in the consolidated income statements for the years ended December 31, 2017, 2016 and 2015, are as follows:

	For the year ended December 31,
Concept	2017			2016			2015
Consolidated income / (loss) before taxes		14,950			3,333			(174,396	)
Average statutory tax rate		30	%		30	%		30	%
Corporate income tax at average statutory tax rate		(4,485	)		(1,000	)		52,319
Income tax of associates, net		1,765			2,110			2,341
Differences in foreign tax rates		3,304			(4,930	)		(2,389	)
Permanent differences		19,324			11,121			(19,456	)
Incentives, deductions, and unrecognized tax losses carryforwards		(20,994	)		(11,110	)		(58,039	)
Change in corporate income tax		(19,331	)		-			884
U.S. Internal Revenue Code Section 382		(96,328	)		-			-
Other non-taxable income/(expense)		(3,092	)		2,143			550
Corporate income tax		(119,837	)		(1,666	)		(23,790	)

Permanent differences in 2017, 2016 and 2015 are mainly due to ACT (Mexico).

The main implications derived from the Tax Cuts and Jobs Act in the U.S. entities are:

A reduction of the Federal income tax rate from 35% to 21%, effective since January 1, 2018. This measure will imply a reduction of the tax burden of the Company. The effect on the deferred tax assets and liabilities has resulted in a $19 million loss;

A limitation of the deduction for net interest expense of all businesses in the U.S. The new limitation is imposed on net interest expense that exceeds 30% of EBITDA from 2018 to 2021, and 30% of EBIT from 2022 onwards. Interests disallowed would be deducted in the future in the event that those limits are not exceeded. After having considered the impacts of Section 382 commented above, the Company does not expect significant negative effects from this net interest expense limitation;

NOLs arising in tax years beginning after 2017 would be limited to 80% of taxable income. For new NOLs recognized after 2017, an indefinite carryforward would be allowed. The limitation of 80% is not applicable for NOLs generated before 2018. For existing NOLs before 2018, a carryforward of 20 years is still applicable. The new limitation does not trigger adverse tax effects to the U.S. subsidiaries of the Company considering the amount of NOLs to be generated in upcoming years and the projected amount of taxable income of these entities after having considered the impacts of Section 382;

Base erosion anti-abuse tax (BEAT): The BEAT applies to certain U.S. corporations that make relevant deductible payments to foreign affiliates. The excess of 10% of a corporation’s taxable income increased by those payments to foreign related parties over its regular tax liability, will be the base erosion tax due. BEAT provisions do not trigger adverse tax consequences for the U.S. subsidiaries of the Company considering the amount of payments made to foreign affiliates for management and support services;

Potential tax erosion in the U.S.: The Company does not expect to have material adverse tax consequences in the U.S. subsidiaries as a result of the measures previously described.

Third-party guarantees and commitments

12 Months Ended

Dec. 31, 2017

Third-party guarantees and commitments [Abstract]

Third-party guarantees and commitments

Note 19.- Third-party guarantees and commitments

Third-party guarantees

At the close of 2017 the overall sum of Bank Bond and Surety Insurance directly deposited by the subsidiaries of the Company as a guarantee to third parties (clients, financial entities and other third parties) amounted to $32,428 thousand attributed to operations of technical nature ($27,163 thousand as of December 31, 2016). In addition, in the third quarter of 2017 the Company issued the guarantees amounting to $112 million previously issued by Abengoa related to operations of technical nature (see Note 10).

Contractual obligations

The following table shows the breakdown of the third-party commitments and contractual obligations as of December 31, 2017 and 2016:

2017	Total		2018		2019 and 2020		2021 and 2022		Subsequent

Corporate debt		643,083		68,907		253,393		107,316		213,467
Loans with credit institutions (project debt)		4,628,289		215,117		457,853		539,466		3,415,853
Notes and bonds (project debt)		846,919		31,174		53,620		54,395		707,730
Purchase commitments		3,149,813		141,867		230,014		259,845		2,518,087
Accrued interest estimate during the useful life of loans		3,129,321		340,481		630,108		559,856		1,598,876

2016	Total		2017		2018 and 2019		2020 and 2021		Subsequent

Corporate debt		668,201		291,861		376,340		-		-
Loans with credit institutions (project debt)*		4,498,930		183,929		388,679		459,361		3,466,961
Notes and bonds (project debt)		831,538		27,225		49,422		48,740		706,151
Purchase commitments		2,894,146		136,032		263,398		246,904		2,247,812
Accrued interest estimate during the useful life of loans		3,356,750		332,408		617,852		543,927		1,862,563

*	According to contracted maturities.

Legal Proceedings

On October 17, 2016, ACT received a request for arbitration from the International Court of Arbitration of the International Chamber of Commerce presented by Pemex. Pemex is requesting compensation for damages caused by a fire that occurred in their facilities during the construction of the ACT cogeneration plant in December 2012, for a total amount of approximately $20 million. On July 5, 2017, Seguros Inbursa, the insurer of Pemex, joined as a second claimant in the process. The Company does not expect this proceeding to have a material adverse effect on their financial position, cash flows or results of operations. In the event that the arbitration results in a negative outcome, the Company expects these damages to be covered by the existing insurance policy.

A number of Abengoa's subcontractors and insurance companies that issued bonds covering such contracts in the United States have included subsidiaries of the Company as co-defendants in claims against Abengoa. Generally, the subsidiaries of the Company have been dismissed as defendants at early stages of the processes but there remain pending cases including Arb Inc. with a potential total claim of approximately $33 million and a group of insurance companies with a potential total claim of approximately $200 million. Based on the assessment of the Company with information currently available, the Company does not expect these proceedings, individually or in the aggregate, to have a material adverse effect on its financial position, cash flows or results of operations.

The Company is not a party to any other significant legal proceeding other than legal proceedings arising in the ordinary course of its business. The Company is party to various administrative and regulatory proceedings that have arisen in the ordinary course of business. While the Company does not expect these proceedings, either individually or in the aggregate, to have a material adverse effect on its financial position or results of operations, because of the nature of these proceedings the Company is not able to predict their ultimate outcomes, some of which may be unfavorable to the Company.

Other operating income and expenses

12 Months Ended

Dec. 31, 2017

Other operating income and expenses [Abstract]

Other operating income and expenses

Note 20.- Other operating income and expenses

The table below shows the detail of Other operating income and expenses for the years ended December 31, 2017, 2016 and 2015:

	For the twelve-month year ended December 31,
Other operating income	2017		2016		2015

Grants		59,707		59,085		67,859
Income from various services and insurance proceeds		21,137		6,453		998
Total		80,844		65,538		68,857

	For the twelve-month year ended December 31,
Other operating expenses	2017			2016			2015
Leases and fees		(6,641	)		(5,309	)		(3,865	)
Operation and maintenance		(129,873	)		(133,292	)		(116,405	)
Independent professional services		(36,178	)		(30,515	)		(19,046	)
Supplies		(20,350	)		(17,177	)		(18,001	)
Insurance		(24,289	)		(23,390	)		(20,277	)
Levies and duties		(52,409	)		(44,440	)		(32,352	)
Other expenses		(14,721	)		(6,195	)		(14,882	)
Total		(284,461	)		(260,318	)		(224,828	)

Grants income mainly relate to ITC cash grants and implicit grants recorded for accounting purposes in relation to the FFB loans with interest rates below market rates in Solana and Mojave projects (See Note 16).

Residual increase in other operating income relates primarily to insurance proceeds from claims in some assets of the Company.

The Company changed the presentation of “Other operating expenses” in 2016 to better reflect the nature of its business and costs. Prior years amounts have been reclassified to conform to the new classification presented in the table above.

Financial Income and expenses

12 Months Ended

Dec. 31, 2017

Financial income and expenses [Abstract]

Financial Income and expenses

Note 21.- Financial Income and expenses

The following table sets forth financial income and expenses for the years ended December 31, 2017, 2016 and 2015:

	For the year ended December 31,
Financial income	2017		2016		2015
Interest income from loans and credits		325		286		933
Interest rates benefits derivatives: cash flow hedges		682		3,012		2,531
Total		1,007		3,298		3,464

	For the year ended December 31,
Financial expenses	2017			2016			2015
Expenses due to interest:
- Loans from credit entities		(253,660	)		(242,919	)		(197,929	)
- Other debts		(137,562	)		(90,995	)		(81,853	)
Interest rates losses derivatives: cash flow hedges		(72,495	)		(74,093	)		(54,139	)
Total		(463,717	)		(408,007	)		(333,921	)

Interests from other debts are primarily interest on the notes issued by ATS, ATN, ATN2, Atlantica Yield and Solaben Luxembourg and interest related to the investment from Liberty. Increase in 2017 is primarily due to the higher increase in the amortized cost of the Liberty debt by $50 million compared to the year 2016 (see Note 16). Losses from interest rate derivatives designated as cash flow hedges correspond primarily to transfers from equity to financial expense when the hedged item is impacting the consolidated income statement.

Other net financial income and expenses

The following table sets out Other net financial income and expenses for the years 2017, 2016 and 2015:

	For the year ended December 31,
Other financial income / (expenses)	2017			2016			2015
Dividend from ACBH (Brazil)		10,383			27,948			18,400
Impairment preferred equity investment in ACBH (see Note 8)		-			(22,076	)		(210,435	)
Other financial income		28,809			13,027			1,520
Other financial losses		(20,758	)		(10,394	)		(9,638	)
Total		18,434			8,505			(200,153	)

According to the agreement reached with Abengoa in the third quarter of 2016, Abengoa acknowledged that Atlantica Yield is the legal owner of the dividends declared on February 24, 2017 and retained from Abengoa amounting to $10.4 million. As a result, the Company recorded $10.4 million as Other financial income in accordance with the accounting treatment previously given to the ACBH dividend.

Other financial losses for the year ended December 31, 2017 consist primarily of a loss resulting from the derecognition of the fair value assigned to ACBH preferred equity investment and recognition of the Abengoa Debt and Equity Instruments for $5.8 million (see Note 8). Residual items presented as Other financial losses are guarantees and letters of credit, wire transfers, other bank fees and other minor financial expenses.

Other financial income consists primarily of $16.2 million income as a result of the termination of the currency swap agreement with Abengoa (see Note 9) and the profit resulting from the sale of the majority of the Abengoa Debt and Equity instruments for $6.5 million (see Note 8).

Earnings per share

12 Months Ended

Dec. 31, 2017

Earnings per share [Abstract]

Earnings per share

Note 22.- Earnings per share

Basic earnings per share for the year 2017 has been calculated by dividing the profit/(loss) attributable to equity holders of the company by the number of shares outstanding. Diluted earnings per share equals basic earnings per share for the period presented.

	For the year ended December 31,
Item	2017			2016			2015
Profit/(loss) from continuing operations attributable to Atlantica Yield Plc.		(111,804	)		(4,855	)		(209,005	)
Profit/(loss) from discontinuing operations attributable to Atlantica Yield Plc.		-			-			-
Average number of ordinary shares outstanding (thousands) - basic and diluted		100,217			100,217			92,795
Earnings per share from continuing operations (US dollar per share) - basic and diluted		(1.12	)		(0.05	)		(2.25	)
Earnings per share from discontinuing operations (US dollar per share) - basic and diluted		-			-			-
Earnings per share from profit/ (loss) for the period (US dollar per share) - basic and diluted		(1.12	)		(0.05	)		(2.25	)

Other information	12 Months Ended
Other information	Dec. 31, 2017
Other information [Abstract]
Other information	Note 23.- Other information 23.1 Restricted Net assets Certain of the consolidated entities are restricted from remitting certain funds to Atlantica Yield plc. as a result of a number of regulatory, contractual or statutory requirements. These restrictions are related to standard requirements to maintain debt service coverage ratios. In addition, some of the assets of the Company have forbearance in relation to cross defaults and change of ownership provisions with Abengoa, under certain conditions. Under the definition of the Securities and Exchange Commission Regulation S-X Rule 12-04, these are also considered restricted for the purposes of this calculation. At December 31, 2017, the accumulated amount of the temporary restrictions for the entire restricted term of these affiliates was $566 million. The Company performed a test on the restricted net assets of consolidated subsidiaries in accordance with Securities and Exchange Commission Regulation S-X Rule 12-04 and concluded the restricted net assets exceeded 25% of the consolidated net assets of the Company as of December 31, 2017. Therefore, the separate financial statements of Atlantica Yield, Plc. do have to be presented (see Appendix V (Schedule I) for details). 23.2 Subsequent events On February 27, 2018, the Board of Directors of the Company approved a dividend of $0.31 per share, which is expected to be paid on or about March 27, 2018.

Schedule I, Condensed Financial Statements

12 Months Ended

Dec. 31, 2017

Schedule I, Condensed Financial Statements [Abstract]

Schedule I, Condensed Financial Statements

Appendix V (Schedule I)

Condensed Financial Statements of Atlantica Yield plc

Condensed statements of financial position of Atlantica Yield Plc.

– Amounts in thousands of usd –

	As of December 31,
	2017		2016
Assets
Investment in affiliates		2,044,967		2,035,598
Loans to affiliates		647,911		704,916
Cash and cash equivalents		148,525		122,154
Other assets		3,704		23,936
Total assets		2,845,107		2,886,604

Liabilities and Equity
Borrowings		386,616		412,839
Notes and bonds		256,468		255,362
Intercompany liabilities		103,796		54,687
Other Liabilities		11,168		10,296
Total Liabilities		758,048		733,184

Common Stock		10,022		10,022
Additional paid-in capital		1,981,881		1,981,881
Distributable reserves		42,410		116,375
Other reserves		181		13,879
Accumulated gains (losses)-net		52,565		31,263
Total shareholders’s equity		2,087,059		2,153,420
Total liabilities and equities		2,845,107		2,886,604

Condensed income statements of Atlantica Yield, Plc.

– Amounts in thousands of usd –

	For the year ended December 31,
	2017			2016			2015
Income from
Services		123,944			114,653			65,170
Other financial income		17,419			8			194
Total income		141,363			114,661			65,364
Expenses
Other operating expenses		(21,173	)		(26,132	)		(10,005	)
Interest		(46,292	)		(35,615	)		(27,783	)
Other financial expenses		(21,333	)		(21,651	)		(246,982	)
Total expenses		(88,798	)		(83,398	)		(284,770	)
Income/(Loss) before income taxes		52,565			31,263			(219,406	)
Income tax benefits/(expense)		-			-			(209	)
Profit/(Loss) for the year		52,565			31,263			(219,615	)

Other comprehensive income statement of Atlantica Yield, Plc.

– Amounts in thousands of usd –

	For the year ended December 31,
	2017			2016		2015

Profit/(loss) for the year		52,565			31,263		(219,615	)
Items that may be subject to transfer to income statement
Change in fair value of cash flow hedges		(13,666	)		7,213		3,683
Net income/(expenses) recognized directly in equity		(13,666	)		7,213		3,683
Cash flow hedges		(32	)		2,321		662
Transfer to income statement		(32	)		2,321		662
Other comprehensive income/(loss) for the year		(13,698	)		9,534		4,345
Total comprehensive income/(loss) for the year		38,867			40,797		(215,270	)

Condensed cash flow statements of Atlantica Yield, Plc.

– Amounts in thousands of usd –

	For the year ended December 31,
	2017			2016			2015
Cash Flow from operating activities		34,937			5,911			(15,943	)
Cash Flow—investing activities
Decrease (increase) in investment and advance to affiliates		151,033			97,341			(939,503	)

Net decrease (increase) in other assets		-			-			(157	)

Cash (used for)/provided by investing activities		151,033			97,341			(939,660	)
Cash Flow—financing activities
Net increase/(decrease) in borrowings and other liabilities		(64,754	)		-			310,462

Dividend paid to shareowner		(94,845	)		(26,585	)		(128,859	)

Capital increase and other		-			-			664,120

Cash from financing activities		(159,599	)		(26,585	)		845,723

Increase (decrease) in cash and cash equivalents during the year		26,371			76,667			(109,880	)

Cash and cash equivalent at the beginning of the year		122,154			45,487			155,367

Cash and cash equivalent at the end of the year		148,525			122,154			45,487

Notes to the Condensed Financial Statements

Schedule I has been provided pursuant to the requirements of Rule 12- 04(a) of Regulation S-X, of the US Securities and Exchange Commission (SEC) which require condensed financial information as to the financial position, change in financial position, results of operations of Atlantica Yield plc, other comprehensive income statement and cash flow statement as of the same dates and for the same periods for which audited consolidated financial statements have been presented when the restricted net assets of consolidated subsidiaries exceed 25 percent of consolidated net assets as of the end of the most recently completed fiscal year.

Certain information and footnote disclosures normally included in financial statements prepared in accordance with International Financial Reporting Standards have been condensed or omitted. The footnote disclosures contain supplemental information only and, as such, these statements should be read in conjunction with the notes to the accompanying consolidated financial statements.

Basis of Presentation.

The presentation of Atlantica Yield plc stands alone condensed financial statement has been prepared using the same accounting policies as set out in the accompanying consolidated financial statements except that, the Company records its investment in subsidiaries under the cost method of accounting and that financial income from credits to companies in the group are recorded under Income from services, given that the company is a holding and this type of service is part of its primary activity. Such investments are presented on the statements of financial position as “Investment in and loans to affiliates” at cost less any identified impairment loss.

As of December 31, 2017, 2016 and 2015 there were no material contingencies, significant provisions of long-term obligations, mandatory dividend or redemption requirements of redeemable stocks or guarantees of the Company, except for those which have been separately disclosed in the Consolidated Financial Statements, if any.

c)	For the year ended December 31, 2017, 2016 and 2015, cash dividend of $10,383 thousand, $29,737 thousand and $18,400 thousand were declared to the Company by its consolidated subsidiaries or associates, respectively.

Reconciliation of the stand-alone to consolidated financial statements of Atlantica Yield Plc.

	For the year ended december 31,
Profit/(Loss) Reconciliation
	2017			2016			2015
Stand-alone—IFRS profit/(loss) for the period		52,565			31,263			(219,615	)
Additional profit/(loss) if subsidiaries had been accounted for using the equity method of accounting as opposed to cost method		(164,369	)		(36,118	)		10,610
Consolidated IFRS profit/(loss) for the period attributable to Atlantica Yield plc		(111,804	)		(4,855	)		(209,005	)

Equity Reconciliation	As of December 31,
	2017			2016			2015

Stand-alone—IFRS shareholders equity		2,087,059			2,153,420			2,158,021
Additional shareholders equity if subsidiaries had been accounted for using the equity method of accounting as opposed to cost method		(191,606	)		(194,309	)		(134,520	)
Consolidated IFRS shareholders equity		1,895,453			1,959,111			2,023,501

Significant accounting policies (Policies)

12 Months Ended

Dec. 31, 2017

Significant accounting policies [Abstract]

Basis of preparation

2.1 Basis of preparation

Application of new accounting standards

a)	Standards, interpretations and amendments effective from January 1, 2017 under IFRS-IASB, applied by the Company in the preparation of these consolidated financial statements:

•

IAS 7 (Amendment) ‘Disclosure Initiative’. Requirements for additional disclosures in order to provide users with improved financial information.

•

IAS 12 (Amendment) ‘Recognition for Deferred Tax for Unrealized Losses’. Clarification of recognition of deferred tax assets for unrealized losses.

•

Annual Improvements to IFRSs 2014-2016 cycles. Amendments to IFRS 12.

b)	Standards, interpretations and amendments published by the IASB that will be effective for periods beginning on or after January 1, 2018:

•

IFRS 9 ‘Financial Instruments’. This Standard is applicable for annual periods beginning on or after January 1, 2018 under IFRS-IASB, earlier application is permitted.

•

IFRS 15 ‘Revenues from Contracts with Customers’. This Standard is applicable for annual periods beginning on or after January 1, 2018 under IFRS-IASB, earlier application is permitted.

•

IFRS 16 ‘Leases’. This Standard is applicable for annual periods beginning on or after January 1, 2019 under IFRS-IASB, earlier application is permitted.

•

IFRS 17 ‘Insurance Contracts’. This Standard is applicable for annual periods beginning on or after January 1, 2021 under IFRS-IASB, earlier application is permitted.

•

IAS 40 (Amendment). Transfers of Investment Property. This amendment is mandatory for annual periods beginning on or after January 1, 2018 under IFRS-IASB, earlier application is permitted.

•

Annual Improvements to IFRSs 2015-2017 cycles. This Standard is applicable for annual periods beginning on or after January 1, 2018 under IFRS-IASB.

•

IFRIC 22 Foreign Currency Transactions and Advance Consideration. This Standard is applicable for annual periods beginning on or after January 1, 2018 under IFRS-IASB.

•

IFRIC 23 Uncertainty over Income Tax Treatments. This Standard is applicable for annual periods beginning on or after January 1, 2019 under IFRS-IASB.

•

The application of these accounting standards is not expected to have a material impact on the consolidated financial statements of the Company.

The analysis performed by the Company, relating to the impact of the new relevant accounting standards is as follows:

IFRS 15 ‘Revenues from contracts with Customers’

Step 1: Identifying the contract with the customer.

Step 2: Identifying the performance obligations.

Step 3: Determining the transaction price.

Step 4: Assigning the transaction price in the performance obligations identified in the contract.

Step 5: Recognition of revenue when (or as) the Company performs the performance obligations.

Currently, assets recorded in accordance with IFRIC 12 are classified as intangible assets or as financial assets, depending on the nature of the payment entitlements established in the contracts.

IFRS 9 ‘Financial Instruments’

Classification and measurement of financial instruments:

The new standard will require some new disclosures, in particular regarding hedge accounting, credit risk and ECLs that will be presented in future periods.

IFRS 16 ‘Leases’

The IASB issued a new lease accounting standard, IFRS 16, in January 2016, which will require the recognition of lease contracts on the consolidated statement of financial position.

Principles to include and record companies in the consolidated financial statements

2.2. Principles to include and record companies in the consolidated financial statements

Controlled entities

Control is achieved when the Company:

Has power over the investee;

Is exposed, or has rights, to variable returns from its involvement with the investee; and

Has the ability to use its power to affect its returns.

The Company reassesses whether or not it controls an investee when facts and circumstances indicate that there are changes to one or more of the three elements of control listed above.

All assets and liabilities between entities of the group, equity, income, expenses, and cash flows relating to transactions between entities of the group are eliminated in full.

Investments accounted for under the equity method

Controlled entities and associates included in these financial statements as of December 31, 2017 and 2016 are set out in appendices.

Contracted concessional assets and price purchase agreements

2.3. Contracted concessional assets and price purchase agreements

Contracted concessional assets and price purchase agreements (PPAs) include fixed assets financed through project debt, related to service concession arrangements recorded in accordance with IFRIC 12, except for Palmucho, which is recorded in accordance with IAS 17 and PS10, PS20 and Seville PV, which are recorded as tangible assets in accordance with IAS 16. The infrastructures accounted for by the Company as concessions are related to the activities concerning electric transmission lines, solar electricity generation plants, cogeneration plants, wind farms and water plants. The useful life of these assets is approximately the same as the length of the concession arrangement. The infrastructure used in a concession can be classified as an intangible asset or a financial asset, depending on the nature of the payment entitlements established in the agreement.

Intangible asset

Once the infrastructure is in operation, the treatment of income and expenses is as follows:

Revenues from the updated annual revenue for the contracted concession, as well as operations and maintenance services are recognized in each period according to IAS 18 “Revenue”.

Operating and maintenance costs and general overheads and administrative costs are recorded in accordance with the nature of the cost incurred (amount due) in each period.

Financing costs are expensed as incurred.

Financial asset

Financing costs are expensed as incurred.

Property, plant and equipment

Once the infrastructure is in operation, the treatment of income and expenses is the same as the one described above for intangible asset.

Borrowing costs

2.4. Borrowing costs

Asset impairment

2.5 Asset impairment

Atlantica Yield reviews its contracted concessional assets to identify any indicators of impairment at least annually.

When the carrying amount of the CGU to which these assets belong is higher than its recoverable amount, the assets are impaired.

Accordingly, the following table provides a summary of the discount rates used (WACC) and growth rates to calculate the recoverable amount for CGUs with the operating segment to which it pertains:

Operating segment	Discount rate			Growth rate
EMEA		4% - 6	%		0	%
North America		4% - 6	%		0	%
South America		5% - 7	%		0	%

Pursuant to IAS 36, an impairment loss is recognized if the carrying amount of these assets exceeds the present value of future cash flows discounted at the initial effective interest rate.

Loans and accounts receivable

2.6 Loans and accounts receivable

Loans and accounts receivable are non-derivative financial assets with fixed or determinable payments, not listed on an active market.

In accordance with IFRIC 12, certain assets under concessions qualify as financial assets and are recorded as is described in Note 2.3.

Pursuant to IAS 36, an impairment loss is recognized if the carrying amount of these assets exceeds the present value of future cash flows discounted at the initial effective interest rate.

Derivative financial instruments and hedging activities

2.7. Derivative financial instruments and hedging activities

Derivatives are recorded at fair value. The Company applies hedge accounting to all hedging derivatives that qualify to be accounted for as hedges under IFRS-IASB.

Fair value estimates

2.8. Fair value estimates

Financial instruments measured at fair value are presented in accordance with the following level classification based on the nature of the inputs used for the calculation of fair value:

Level 1: Inputs are quoted prices in active markets for identical assets or liabilities.

Level 3: Fair value is measured based on unobservable inputs for the asset or liability.

Atlantica Yield derivatives correspond primarily to the interest rate swaps designated as cash flow hedges, which are classified as Level 2:

Description of the valuation method

Variables (Inputs)

Clients and other receivables

2.9. Clients and other receivables

An allowance for doubtful accounts is recorded when there is objective evidence that the Company will not be able to recover all amounts due as per the original terms of the receivables.

Cash and cash equivalents

2.10. Cash and cash equivalents

Grants

2.11. Grants

Loans and borrowings

2.12. Loans and borrowings

Bonds and notes

2.13. Bonds and notes

Income taxes

2.14. Income taxes

Deferred tax assets are recognized only when it is probable that sufficient future taxable profit will be available to use deferred tax assets.

Trade payables and other liabilities

2.15. Trade payables and other liabilities

Foreign currency transactions

2.16. Foreign currency transactions

Results of companies carried under the equity method are translated at the average annual exchange rate.

Equity

2.17. Equity

Parent company reserves together with the Share capital represent the Parent’s net investment in the entities included in these consolidated financial statements.

Provisions and contingencies

2.18. Provisions and contingencies

Provisions are recognized when:

there is a present obligation, either legal or constructive, as a result of past events;

it is more likely than not that there will be a future outflow of resources to settle the obligation; and

the amount has been reliably estimated.

Use of estimates

2.19. Use of estimates

The most critical accounting policies, which reflect significant management estimates and judgment to determine amounts in these consolidated financial statements, are as follows:

Contracted concessional agreements and PPAs.

Impairment of intangible assets and property, plant and equipment.

Assessment of control.

Derivative financial instruments and fair value estimates.

Income taxes and recoverable amount of deferred tax assets.

Nature of the business (Tables)

12 Months Ended

Dec. 31, 2017

Overview of concessional assets

Assets	Type	Ownership	Location	Currency⁽⁸⁾	Capacity (Gross)	Counterparty Credit Ratings⁽⁹⁾	COD*	Contract Years Left ⁽¹²⁾

Solana	Renewable (Solar)	100% Class B⁽¹⁾	Arizona (USA)	USD	280 MW	A-/A3/A-	4Q 2013	26

Mojave	Renewable (Solar)	100%	California (USA)	USD	280 MW	A-/A3/A-	4Q 2014	22

Solaben 2 & 3	Renewable (Solar)	70%⁽²⁾	Spain	Euro	2x50 MW	BBB+/Baa2/A-	3Q 2012 & 2Q 2012	20&19

Solacor 1 & 2	Renewable (Solar)	87%⁽³⁾	Spain	Euro	2x50 MW	BBB+/Baa2/A-	1Q 2012 & 1Q 2012	19

PS10/PS20	Renewable (Solar)	100%	Spain	Euro	31 MW	BBB+/Baa2/A-	1Q 2007 & 2Q 2009	14&16

Helioenergy 1 & 2	Renewable (Solar)	100%	Spain	Euro	2x50 MW	BBB+/Baa2/A-	3Q 2011& 4Q 2011	19

Helios 1 & 2	Renewable (Solar)	100%	Spain	Euro	2x50 MW	BBB+/Baa2/A-	3Q 2012& 3Q 2012	20

Solnova 1, 3 & 4	Renewable (Solar)	100%	Spain	Euro	3x50 MW	BBB+/Baa2/A-	2Q 2010 & 2Q 2010& 3Q 2010	17&17&18

Solaben 1 & 6	Renewable (Solar)	100%	Spain	Euro	2x50 MW	BBB+/Baa2/A-	3Q 2013	21

Kaxu	Renewable (Solar)	51%⁽⁴⁾	South Africa	Rand	100 MW	BB/Baa3/BB+⁽¹⁰⁾	1Q 2015	17

Palmatir	Renewable (Wind)	100%	Uruguay	USD	50 MW	BBB/Baa2/BBB-⁽¹¹⁾	2Q 2014	16

Cadonal	Renewable (Wind)	100%	Uruguay	USD	50 MW	BBB/Baa2/BBB-⁽¹¹⁾	4Q 2014	17

ACT	Efficient natural gas	100%	Mexico	USD	300 MW	BBB+/A3/ BBB+	2Q 2013	15

ATN	Transmission line	100%	Peru	USD	362 miles	BBB+/A3/BBB+	1Q 2011	23

ATS	Transmission line	100%	Peru	USD	569 miles	BBB+/A3/BBB+	1Q 2014	26

ATN 2	Transmission line	100%	Peru	USD	81 miles	Not rated	2Q 2015	15

Quadra 1	Transmission line	100%	Chile	USD	49 miles	Not rated	2Q 2014	17

Quadra 2	Transmission line	100%	Chile	USD	32 miles	Not rated	1Q 2014	17

Palmucho	Transmission line	100%	Chile	USD	6 miles	BBB+/Baa2/BBB+	4Q 2007	20

Skikda	Water	34.2%⁽⁵⁾	Algeria	USD	3.5 M ft3/day	Not rated	1Q 2009	16

Honaine	Water	25.5%⁽⁶⁾	Algeria	USD	7 M ft3/ day	Not rated	3Q 2012	20

Seville PV	Renewable (Solar)	80%⁽⁷⁾	Spain	Euro	1 MW	BBB+/Baa2/A-	3Q 2006	18

(1)

(2)	Itochu Corporation, a Japanese trading company, holds 30% of the shares in each of Solaben 2 and Solaben 3.

(3)	JGC, a Japanese engineering company, holds 13% of the shares in each of Solacor 1 and Solacor 2.

(4)	Kaxu is owned by the Company (51%), Industrial Development Corporation of South Africa (29%) and Kaxu Community Trust (20%).

(5)	Algerian Energy Company, SPA owns 49% of Skikda and Valoriza Agua, S.L. owns the remaining 16.83%.

(6)	Algerian Energy Company, SPA owns 49% of Honaine and Valoriza Agua, S.L. owns the remaining 25.5%.

(7)	Instituto para la Diversificación y Ahorro de la Energía (“Idae”), a Spanish state owned company, holds 20% of the shares in Seville PV.

(8)	Certain contracts denominated in U.S. dollars are payable in local currency.

(9)	Reflects the counterparty’s credit ratings issued by Standard & Poor’s Ratings Services, or S&P, Moody’s Investors Service Inc., or Moody’s, and Fitch Ratings Ltd, or Fitch.

(10)	Refers to the credit rating of the Republic of South Africa. The offtaker is Eskom, which is a state-owned utility company in South Africa.

(11)	Refers to the credit rating of Uruguay, as UTE (Administración Nacional de Usinas y Transmisoras Eléctricas) is unrated.

(12)	As of December 31, 2017.

* Commercial Operation Date (“COD”).

Financial information by segment (Tables)

12 Months Ended

Dec. 31, 2017

Financial information by segment [Abstract]

Revenues and Further Adjusted EBITDA, assets and liabilities by operating segments and business sectors

The following tables show Revenues and Further Adjusted EBITDA by operating segments and business sectors for the years 2017, 2016 and 2015:

	Revenue									Further Adjusted EBITDA
	For the year ended December 31,									For the year ended December 31,
Geography	2017			2016			2015			2017			2016			2015
North America		$	332,705		$	337,061		$	328,139		$	282,328		$	284,691		$	279,559
South America			120,797			118,764			112,480			108,766			124,599			110,905
EMEA			554,879			515,972			350,262			388,216			354,020			233,754
Total		$	1,008,381		$	971,797		$	790,881		$	779,310		$	763,310		$	624,218

	Revenue									Further Adjusted EBITDA
	For the year ended December 31,									For the year ended December 31,
Business sectors	2017			2016			2015			2017			2016			2015
Renewable energy		$	767,226		$	724,325		$	543,012		$	569,193		$	538,427		$	413,933
Efficient natural gas			119,784			128,046			138,717			106,140			106,492			107,671
Electric transmission lines			95,096			95,137			86,393			87,695			104,795			89,047
Water			26,275			24,288			22,759			16,282			13,596			13,567
Total		$	1,008,381		$	971,797		$	790,881		$	779,310		$	763,310		$	624,218

The reconciliation of segment Further Adjusted EBITDA with the profit/(loss) attributable to the parent company is as follows:

	For the year ended December 31,
	2017			2016			2015
Loss attributable to the Company	$	(111,804	)	$	(4,855	)	$	(209,005	)
Profit attributable to non-controlling interests		6,917			6,522			10,819
Income tax		119,837			1,666			23,790
Share of profits/(losses) of associates		(5,351	)		(6,646	)		(7,844	)
Dividend from exchangeable preferred equity investment in ACBH (Note 21)		10,383			27,948			18,400
Financial expense, net		448,368			405,750			526,758
Depreciation, amortization, and impairment charges		310,960			332,925			261,301
Total segment Further Adjusted EBITDA	$	779,310		$	763,310		$	624,219

Assets and liabilities by geography

The assets and liabilities by operating segments (and business sector) at the end of 2017 and 2016 are as follows:

Assets and liabilities by geography as of December 31, 2017:

	North America		South America		EMEA		Balance as of December 31, 2017
Assets allocated
Contracted concessional assets		3,770,169		1,100,778		4,213,323		9,084,270
Investments carried under the equity method		-		-		55,784		55,784
Current financial investments		116,451		59,831		31,263		207,545
Cash and cash equivalents (project companies)		149,236		42,548		329,078		520,862
Subtotal allocated		4,035,856		1,203,157		4,629,448		9,868,461
Unallocated assets
Other non-current assets								210,378
Other current assets (including cash and cash equivalents at holding company level)								413,500
Subtotal unallocated								623,878
Total assets								10,492,339

	North America		South America		EMEA		Balance as of December 31, 2017
Liabilities allocated
Long-term and short-term project debt		1,821,102		876,063		2,778,043		5,475,208
Grants and other liabilities		1,593,048		810		42,202		1,636,060
Subtotal allocated		3,414,150		876,873		2,820,245		7,111,268
Unallocated liabilities
Long-term and short-term corporate debt								643,083
Other non-current liabilities								657,345
Other current liabilities								185,190
Subtotal unallocated								1,485,618
Total liabilities								8,596,886
Equity unallocated								1,895,453
Total liabilities and equity unallocated								3,381,071
Total liabilities and equity								10,492,339

Assets and liabilities by geography as of December 31, 2016:

	North America		South America		EMEA		Balance as of December 31, 2016
Assets allocated
Contracted concessional assets		3,920,106		1,144,712		3,859,454		8,924,272
Investments carried under the equity method		-		-		55,009		55,009
Current financial investments		136,665		62,215		29,158		228,038
Cash and cash equivalents (project companies)		185,970		40,015		246,671		472,656
Subtotal allocated		4,242,741		1,246,942		4,190,291		9,679,975
Unallocated assets
Other non-current assets								272,664
Other current assets (including cash and cash equivalents at holding company level)								345,160
Subtotal unallocated								617,824
Total assets								10,297,799

	North America		South America		EMEA		Balance as of December 31, 2016
Liabilities allocated
Long-term and short-term project debt		1,870,861		895,316		2,564,290		5,330,467
Grants and other liabilities		1,575,303		1,512		35,230		1,612,045
Subtotal allocated		3,446,164		896,828		2,599,520		6,942,512
Unallocated liabilities
Long-term and short-term corporate debt								668,201
Other non-current liabilities								546,053
Other current liabilities								181,922
Subtotal unallocated								1,396,176
Total liabilities								8,338,688
Equity unallocated								1,959,111
Total liabilities and equity unallocated								3,355,287
Total liabilities and equity								10,297,799

Assets and liabilities by business sectors

Assets and liabilities by business sectors as of December 31, 2017:

	Renewable energy		Efficient natural gas		Electric transmission lines		Water		Balance as of December 31, 2017
Assets allocated
Contracted concessional assets		7,436,362		660,387		897,269		90,252		9,084,270
Investments carried under the equity method		12,419		-		-		43,365		55,784
Current financial investments		17,249		116,430		59,289		14,577		207,545
Cash and cash equivalents (project companies)		452,792		39,064		15,325		13,681		520,862
Subtotal allocated		7,918,822		815,881		971,883		161,875		9,868,461
Unallocated assets
Other non-current assets										210,378
Other current assets (including cash and cash equivalents at holding company level)										413,500
Subtotal unallocated										623,878
Total assets										10,492,339

	Renewable energy		Efficient natural gas		Electric transmission lines		Water		Balance as of December 31, 2017
Liabilities allocated
Long-term and short-term project debt		4,162,596		579,173		698,346		35,093		5,475,208
Grants and other liabilities		1,635,508		552		-		-		1,636,060
Subtotal allocated		5,798,104		579,725		698,346		35,093		7,111,268
Unallocated liabilities
Long-term and short-term corporate debt										643,083
Other non-current liabilities										657,345
Other current liabilities										185,190
Subtotal unallocated										1,485,618
Total liabilities										8,596,886
Equity unallocated										1,895,453
Total liabilities and equity unallocated										3,381,071
Total liabilities and equity										10,492,339

Assets and liabilities by business sectors as of December 31, 2016:

	Renewable energy		Efficient natural gas		Electric transmission lines		Water		Balance as of December 31, 2016
Assets allocated
Contracted concessional assets		7,255,308		646,927		929,005		93,032		8,924,272
Investments carried under the equity method		12,953		-		-		42,056		55,009
Current financial investments		13,661		136,644		62,215		15,518		228,038
Cash and cash equivalents (project companies)		420,215		30,295		11,357		10,789		472,656
Subtotal allocated		7,702,137		813,866		1,002,577		161,395		9,679,975
Unallocated assets
Other non-current assets										272,664
Other current assets (including cash and cash equivalents at holding company level)										345,160
Subtotal unallocated										617,824
Total assets										10,297,799

	Renewable energy		Efficient natural gas		Electric transmission lines		Water		Balance as of December 31, 2016
Liabilities allocated
Long-term and short-term project debt		3,979,096		598,256		711,517		41,598		5,330,467
Grants and other liabilities		1,611,067		239		739		-		1,612,045
Subtotal allocated		5,590,163		598,495		712,256		41,598		6,942,512
Unallocated liabilities
Long-term and short-term corporate debt										668,201
Other non-current liabilities										546,053
Other current liabilities										181,922
Subtotal unallocated										1,396,176
Total liabilities										8,338,688
Equity unallocated										1,959,111
Total liabilities and equity unallocated										3,355,287
Total liabilities and equity										10,297,799

Depreciation, amortization and impairment charges recognized

The amount of depreciation, amortization and impairment charges recognized for the years ended December 31, 2017, 2016 and 2015 are as follows:

	For the year ended December 31,
Depreciation, amortization and impairment by geography	2017			2016			2015
North America		(123,726	)		(129,478	)		(129,091	)
South America		(40,880	)		(62,387	)		(41,274	)
EMEA		(146,354	)		(141,060	)		(90,936	)
Total		(310,960	)		(332,925	)		(261,301	)

	For the year ended December 31,
Depreciation, amortization and impairment by business sectors	2017			2016			2015
Renewable energy		(282,376	)		(304,235	)		(232,699	)
Electric transmission lines		(28,584	)		(28,690	)		(28,602	)
Total		(310,960	)		(332,925	)		(261,301	)

Contracted concessional assets (Tables)

12 Months Ended

Dec. 31, 2017

Contracted concessional assets [Abstract]

Movements of contracted concessional assets

The following table shows the movements of contracted concessional assets included in the heading “Contracted Concessional assets” for 2017:

Cost

Total as of January 1, 2017	10,067,596
Additions	15,426
Subtractions	(42,500	)
Translation differences	593,247
Total as of December 31, 2017	10,633,769

Accumulated amortization

Total as of January 1, 2017	(1,143,324	)
Additions	(309,846	)
Translation differences	(96,329	)
Total accum. amort. as of December 31, 2017	(1,549,499	)
Net balance at December 31, 2017	9,084,270

The following table shows the movements of contracted concessional assets included in the heading “Contracted Concessional assets” for 2016:

Cost

Total as of January 1, 2016	10,126,023
Additions	6,346
Translation differences	(68,199	)
Change in the scope of the consolidated financial statements	5,876
Reclassification and other movements	(2,450	)

Total as of December 31, 2016	10,067,596

Accumulated amortization

Total as of January 1, 2016	(825,126	)
Additions	(332,925	)
Change in the scope of the consolidated financial statements	(2,381	)
Translation differences	17,108
Total accum. amort. as of December 31, 2016	(1,143,324	)
Net balance at December 31, 2016	8,924,272

Investments carried under the equity method (Tables)

12 Months Ended

Dec. 31, 2017

Investments carried under the equity method [Abstract]

Investments in associates

The table below shows the breakdown and the movement of the investments held in associates for 2017 and 2016:

Investments in associates	2017			2016
Initial balance		55,009			56,181
Share of (loss)/profit		5,351			6,646
Dividend distribution		(2,454	)		(3,954	)
Equity distribution		(549	)		(3,099	)
Currency translation differences		(1,573	)		(765	)
Final balance		55,784			55,009

Stand-alone amounts for associated companies

The tables below show a breakdown of stand-alone amounts of assets, revenues and profit and loss as well as other information of interest for the years 2017 and 2016 for the associated companies:

Company	% Shares		Non- current assets		Current assets		Non- current liabilities		Current liabilities		Revenue		Operating profit/ (loss)			Net profit/ (loss)			Investment under the equity method
Evacuación Valdecaballeros, S.L.		57.16		21,306		841		373		451		298		(708	)		(730	)		9,175
Myah Bahr Honaine, S.P.A.(*)		25.50		195,275		64,114		91,205		12,649		46,767		28,468			24,464			43,365
Pectonex, R.F. Proprietary Limited		50.00		3,904		-		-		2		-		(206	)		(206	)		3,244
Evacuación Villanueva del Rey, S.L		40.02		3,526		53		2,265		190		-		37			-			-
As of December 31, 2017				240,011		65,008		93,843		13,292		47,065		27,591			23,528			55,784

Company	% Shares		Non- current assets		Current assets		Non- current liabilities		Current liabilities		Revenue		Operating profit/ (loss)			Net profit/ (loss)			Investment under the equity method
Evacuación Valdecaballeros, S.L.		57.16		19,283		931		306		532		537		(545	)		(565	)		9,528
Myah Bahr Honaine, S.P.A.(*)		25.50		202,150		67,120		104,704		14,158		52,770		34,247			29,990			42,056
Pectonex, R.F. Proprietary Limited		50.00		3,730		-		-		1		-		(187	)		(187	)		3,425
Evacuación Villanueva del Rey, S.L		40.02		3,251		17		2,118		142		-		31			-			-
As of December 31, 2016				228,684		68,068		107,128		14,833		53,307		33,546			29,238			55,009

Financial instruments by category (Tables)

12 Months Ended

Dec. 31, 2017

Financial instruments by category [Abstract]

Financial assets

	Notes		Loans and receivables / payables		Available for sale financial assets		Hedging derivatives		Balance as of December 31, 2017
Derivative assets		9		-		-		8,230		8,230
Investment in Ten West Link				2,088		-		-		2,088
Abengoa debt and Equity instruments				-		1,715		-		1,715
Other financial investments				243,347		-		-		243,347
Clients and other receivables		11		244,449		-		-		244,449
Cash and cash equivalents		12		669,387		-		-		669,387
Total financial assets				1,159,271		1,715		8,230		1,169,216

	Notes		Loans and receivables / payables		Available for sale financial assets		Hedging derivatives		Balance as of December 31, 2016
Derivative assets		9		-		-		3,822		3,822
Preferred equity in ACBH				-		30,488		-		30,488
Other financial investments				263,501		-		-		263,501
Clients and other receivables		11		207,621		-		-		207,621
Cash and cash equivalents		12		594,811		-		-		594,811
Total financial assets				1,065,933		30,488		3,822		1,100,243

Financial liabilities

Corporate debt	14	643,083	-	-	643,083
Project debt	15	5,475,208	-	-	5,475,208
Related parties – non-current	10	141,031	-	-	141,031
Trade and other current liabilities	17	155,144	-	-	155,144
Derivative liabilities	9	-	-	329,731	329,731
Total financial liabilities		6,414,466	-	329,731	6,744,197

Corporate debt	14	668,201	-	-	668,201
Project debt	15	5,330,467	-	-	5,330,467
Related parties – non-current	10	101,750	-	-	101,750
Trade and other current liabilities	17	160,505	-	-	160,505
Derivative liabilities	9	-	-	349,266	349,266
Total financial liabilities		6,260,923	-	349,266	6,610,189

Derivative financial instruments (Tables)

12 Months Ended

Dec. 31, 2017

Derivative financial instruments [Abstract]

Fair value amount of derivative financial instruments

The breakdowns of the fair value amount of the derivative financial instruments as of December 31, 2017 and 2016 are as follows:

Balance as of December 31, 2017

Balance as of December 31, 2016

Assets

Liabilities

Assets

Liabilities

Derivatives - cash flow hedge

8,230

329,731

3,822

349,266

Maturities of notional and fair value amounts of interest rate derivatives designated as cash flow hedges

The table below shows a breakdown of the maturities of notional amounts of derivatives designated as cash flow hedges as of December 31, 2017 and 2016.

Notionals	Balance as of December 31, 2017				Balance as of December 31, 2016
	Cap		Swap		Cap		Swap
Up to 1 year		42,324		139,939		24,261		75,837
Between 1 and 2 years		45,422		94,285		25,934		199,832
Between 2 and 3 years		48,215		103,536		27,880		83,897
Subsequent years		620,378		1,893,850		400,239		1,500,789
Total	$	756,339	$	2,231,611	$	478,314	$	1,860,355

Fair value	Balance as of December 31, 2017					Balance as of December 31, 2016
	Cap		Swap			Cap		Swap
Up to 1 year		347		(13,224	)		250		(12,383	)
Between 1 and 2 years		978		(14,378	)		262		(14,927	)
Between 2 and 3 years		396		(15,923	)		275		(13,957	)
Subsequent years		6,509		(286,206	)		3,035		(307,999	)
Total	$	8,230		(329,731	)	$	3,822		(349,266	)

Related parties (Tables)

12 Months Ended

Dec. 31, 2017

Related parties [Abstract]

Related party receivables and payables

Details of balances with related parties as of December 31, 2017 and 2016 are as follows:

	Balance as of December 31,
	2017		2016

Credit receivables (current)		11,567		12,031
Total current receivables with related parties		11,567		12,031

Credit receivables (non-current)		2,108		30,505
Total non-current receivables with related parties		2,108		30,505

Trade payables (current)		63,409		61,338
Total current payables with related parties		63,409		61,338

Credit payables (non-current)		141,031		101,750
Total non-current payables with related parties		141,031		101,750

Related party transactions

	For the year ended December 31,
	2017			2016			2015
Sales		-			-			44,260
Services rendered		3,495			1,220			523
Services received		(114,416	)		(115,779	)		(106,737	)
Financial income		74			60			1,466
Financial expenses		(1,154	)		(2,460	)		(1,968	)

Clients and other receivable (Tables)

12 Months Ended

Dec. 31, 2017

Clients and other receivable [Abstract]

Clients and other receivable

Clients and other receivable as of December 31, 2017 and 2016, consist of the following:

	Balance as of December 31,
	2017		2016
Trade receivables		186,728		151,199
Tax receivables		39,607		29,705
Prepayments		6,375		10,261
Other accounts receivable		11,739		16,456
Total		244,449		207,621

Trade receivables in foreign currency

Trade receivables in foreign currency as of December 31, 2017 and 2016, are as follows:

	Balance as of December 31,
	2017		2016
Euro		109,165		98,798
Rand		23,792		12,807
Other		7,363		7,151
Total		140,320		118,756

Maturity of trade receivables

The following table shows the maturity of Trade receivables as of December 31, 2017 and 2016:

	Balance as of December 31,
	2017		2016

Up to 3 months		186,728		151,199
Total		186,728		151,199

Corporate debt (Tables)

12 Months Ended

Dec. 31, 2017

Corporate debt [Abstract]

Repayment schedule for corporate debt

The breakdown of the corporate debt as of December 31, 2017 and 2016 is as follows:

	Balance as of December 31,
Non-current	2017		2016
Credit Facilities with financial entities		320,783		123,804
Notes and Bonds		253,393		252,536
Total Non-Current		574,176		376,340

	Balance as of December 31,
Current	2017		2016
Credit Facilities with financial entities		65,833		289,035
Notes and Bonds		3,074		2,826
Total Current		68,907		291,861

The repayment schedule for the Corporate debt, at the end of 2017 is as follows:

	2018		2019		2020		2021		2022		Subsequent years		Total
Credit Facility Tranche A		53,778		-		-		-		-		-		53,778
Note Issuance Facility		107		-		-		-		107,316		213,467		320,890
Credit Facility 2017		11,948		-		-		-		-		-		11,948
2019 Notes		3,074		253,393		-		-		-		-		256,467
Total		68,907		253,393		-		-		107,316		213,467		643,083

Movement in corporate debt

The following table details the movement in Corporate debt for the year 2017, split between cash and non-cash items:

		January 1, 2017				Cash Flow				Non-cash changes				December 31, 2017
Corporate debt			668,201				(68,372	)			43,254				643,083

Project debt (Tables)

12 Months Ended

Dec. 31, 2017

Project debt [Abstract]

Project debt

The variations for 2017 and 2016 of project debt have been the following:

	Project debt - long term			Project debt - short term			Total
Balance as of December 31, 2016		4,629,184			701,283			5,330,467
Increases		52,027			304,707			356,734
Decreases		(42,560	)		(509,131	)		(551,691	)
Currency translation differences		316,646			23,052			339,698
Reclassifications		273,620			(273,620	)		-
Balance as of December 31, 2017		5,228,917			246,291			5,475,208

	Project debt - long term			Project debt - short term			Total
Balance as of December 31, 2015		3,574,464			1,896,205			5,470,669
Increases		36,842			329,434			366,276
Decreases		-			(480,969	)		(480,969	)
Currency translation differences		(64,426	)		38,917			(25,509	)
Reclassifications		1,082,304			(1,082,304	)		-
Balance as of December 31, 2016		4,629,184			701,283			5,330,467

Repayment schedule for project debt

The repayment schedule for Project debt in accordance with the financing arrangements, at the end of 2017 is as follows and is consistent with the projected cash flows of the related projects.

2018			2019		2020		2021		2022		Subsequent years		Total
Interest Repayment	Nominal repayment
21,612		224,679		246,471		265,002		280,303		313,559		4,123,582		5,475,208

Movement in project debt

The following table details the movement in Project debt for the year 2017, split between cash and non-cash items:

		January 1, 2017				Cash Flow				Non-cash changes				December 31, 2017
Project debt			5,330,467				(248,472	)			393,212				5,475,208

Foreign currency-denominated project debt

The equivalent in U.S. dollars of the most significant foreign-currency-denominated debts held by the Company is as follows:

	Balance as of December 31,
Currency	2017		2016
Euro		2,286,771		2,102,985
Algerian Dinar		35,093		41,598
Rand		456,179		419,708
Total		2,778,043		2,564,291

Income Tax (Tables)

12 Months Ended

Dec. 31, 2017

Income Tax [Abstract]

Analysis of deferred tax assets and liabilities

As of December 31, 2017, and 2016, the analysis of deferred tax assets and deferred tax liabilities is as follows:

Deferred tax assets	Balance as of December 31,
Concept	2017		2016
Net tax credits for operating losses carryforwards		71,219		102,804
Temporary differences derivatives financial instruments		93,719		99,930
Other temporary differences		198		157
Total deferred tax assets		165,136		202,891

Deferred tax liabilities	Balance as of December 31,
Concept	2017		2016
Temporary differences tax/book amortization		113,432		28,810
Other temporary differences tax/book value of contracted concessional assets		66,247		61,818
Other temporary differences		6,904		4,409
Total deferred tax liabilities		186,583		95,037

Movements in deferred tax assets and liabilities

The movements in deferred tax assets and liabilities during the years ended December 31, 2017 and 2016 were as follows:

Deferred tax assets	Amount
As of January 1, 2016		191,314
Increase/decrease through the consolidated income statement		16,033
Increase/decrease through other consolidated comprehensive income (equity)		(5,701	)
Other movements		1,245
As of December 31, 2016		202,891

Increase/decrease through the consolidated income statement		(31,421	)
Increase/decrease through other consolidated comprehensive income (equity)		(13,312	)
Other movements		6,978
As of December 31, 2017		165,136

Deferred tax liabilities	Amount
As of January 1, 2016		79,654
Increase/decrease through the consolidated income statement		16,681
Increase/decrease through other consolidated comprehensive income (equity)		(62	)
Other movements		(1,236	)
As of December 31, 2016		95,037

Increase/decrease through the consolidated income statement		86,418
Increase/decrease through other consolidated comprehensive income (equity)		-
Other movements		5,128
As of December 31, 2017		186,583

Income tax benefit/(expense)

Details for income tax for the years ended December 31, 2017, 2016 and 2015 are as follows:

	For the twelve-month period ended December 31,
Item	2017			2016			2015
Current tax		(1,998	)		(1,018	)		(2,182	)
Deferred tax		(117,839	)		(648	)		(21,608	)
- relating to the origination and reversal of temporary differences		(98,508	)		(648	)		(22,492	⁾
- relating to changes in tax rates		(19,331	)		-			884
Total income tax benefit/(expense)		(119,837	)		(1,666	)		(23,790	)

Effective income tax rate reconciliation

	For the year ended December 31,
Concept	2017			2016			2015
Consolidated income / (loss) before taxes		14,950			3,333			(174,396	)
Average statutory tax rate		30	%		30	%		30	%
Corporate income tax at average statutory tax rate		(4,485	)		(1,000	)		52,319
Income tax of associates, net		1,765			2,110			2,341
Differences in foreign tax rates		3,304			(4,930	)		(2,389	)
Permanent differences		19,324			11,121			(19,456	)
Incentives, deductions, and unrecognized tax losses carryforwards		(20,994	)		(11,110	)		(58,039	)
Change in corporate income tax		(19,331	)		-			884
U.S. Internal Revenue Code Section 382		(96,328	)		-			-
Other non-taxable income/(expense)		(3,092	)		2,143			550
Corporate income tax		(119,837	)		(1,666	)		(23,790	)

Third-party guarantees and commitments (Tables)

12 Months Ended

Dec. 31, 2017

Third-party guarantees and commitments [Abstract]

Contractual obligations

The following table shows the breakdown of the third-party commitments and contractual obligations as of December 31, 2017 and 2016:

2017	Total		2018		2019 and 2020		2021 and 2022		Subsequent

Corporate debt		643,083		68,907		253,393		107,316		213,467
Loans with credit institutions (project debt)		4,628,289		215,117		457,853		539,466		3,415,853
Notes and bonds (project debt)		846,919		31,174		53,620		54,395		707,730
Purchase commitments		3,149,813		141,867		230,014		259,845		2,518,087
Accrued interest estimate during the useful life of loans		3,129,321		340,481		630,108		559,856		1,598,876

2016	Total		2017		2018 and 2019		2020 and 2021		Subsequent

Corporate debt		668,201		291,861		376,340		-		-
Loans with credit institutions (project debt)*		4,498,930		183,929		388,679		459,361		3,466,961
Notes and bonds (project debt)		831,538		27,225		49,422		48,740		706,151
Purchase commitments		2,894,146		136,032		263,398		246,904		2,247,812
Accrued interest estimate during the useful life of loans		3,356,750		332,408		617,852		543,927		1,862,563

*	According to contracted maturities.

Other operating income and expenses (Tables)

12 Months Ended

Dec. 31, 2017

Other operating income and expenses [Abstract]

Other operating income

The table below shows the detail of Other operating income and expenses for the years ended December 31, 2017, 2016 and 2015:

	For the twelve-month year ended December 31,
Other operating income	2017		2016		2015

Grants		59,707		59,085		67,859
Income from various services and insurance proceeds		21,137		6,453		998
Total		80,844		65,538		68,857

Other operating expenses

	For the twelve-month year ended December 31,
Other operating expenses	2017			2016			2015
Leases and fees		(6,641	)		(5,309	)		(3,865	)
Operation and maintenance		(129,873	)		(133,292	)		(116,405	)
Independent professional services		(36,178	)		(30,515	)		(19,046	)
Supplies		(20,350	)		(17,177	)		(18,001	)
Insurance		(24,289	)		(23,390	)		(20,277	)
Levies and duties		(52,409	)		(44,440	)		(32,352	)
Other expenses		(14,721	)		(6,195	)		(14,882	)
Total		(284,461	)		(260,318	)		(224,828	)

Financial Income and expenses (Tables)

12 Months Ended

Dec. 31, 2017

Financial income and expenses [Abstract]

Financial income

The following table sets forth financial income and expenses for the years ended December 31, 2017, 2016 and 2015:

	For the year ended December 31,
Financial income	2017		2016		2015
Interest income from loans and credits		325		286		933
Interest rates benefits derivatives: cash flow hedges		682		3,012		2,531
Total		1,007		3,298		3,464

Financial expenses

	For the year ended December 31,
Financial expenses	2017			2016			2015
Expenses due to interest:
- Loans from credit entities		(253,660	)		(242,919	)		(197,929	)
- Other debts		(137,562	)		(90,995	)		(81,853	)
Interest rates losses derivatives: cash flow hedges		(72,495	)		(74,093	)		(54,139	)
Total		(463,717	)		(408,007	)		(333,921	)

Other net financial income and expenses

The following table sets out Other net financial income and expenses for the years 2017, 2016 and 2015:

	For the year ended December 31,
Other financial income / (expenses)	2017			2016			2015
Dividend from ACBH (Brazil)		10,383			27,948			18,400
Impairment preferred equity investment in ACBH (see Note 8)		-			(22,076	)		(210,435	)
Other financial income		28,809			13,027			1,520
Other financial losses		(20,758	)		(10,394	)		(9,638	)
Total		18,434			8,505			(200,153	)

Earnings per share (Tables)

12 Months Ended

Dec. 31, 2017

Earnings per share [Abstract]

Earnings per share

	For the year ended December 31,
Item	2017			2016			2015
Profit/(loss) from continuing operations attributable to Atlantica Yield Plc.		(111,804	)		(4,855	)		(209,005	)
Profit/(loss) from discontinuing operations attributable to Atlantica Yield Plc.		-			-			-
Average number of ordinary shares outstanding (thousands) - basic and diluted		100,217			100,217			92,795
Earnings per share from continuing operations (US dollar per share) - basic and diluted		(1.12	)		(0.05	)		(2.25	)
Earnings per share from discontinuing operations (US dollar per share) - basic and diluted		-			-			-
Earnings per share from profit/ (loss) for the period (US dollar per share) - basic and diluted		(1.12	)		(0.05	)		(2.25	)

Nature of the business, Description (Details) $ / shares in Units, $ in Thousands				12 Months Ended
	May 14, 2015 $ / shares	Jan. 22, 2015 USD ($) $ / shares	Jun. 18, 2014 USD ($) $ / shares shares	Dec. 31, 2017	Dec. 31, 2014 USD ($) ConcessionalAsset	Feb. 28, 2017
Nature of the business [Abstract]
Shares issued (in shares) \| shares			24,850,000
Share price (in dollars per share) \| $ / shares	$ 33.14		$ 29
Proceeds from issuing shares			$ 720,650
Interest consideration transferred						12.50%
Subsidiary of Abengoa [Member]
Nature of the business [Abstract]
Shares purchased by underwriters (in shares) \| shares			3,727,500
Total proceeds from offering			$ 828,748
Abengoa [Member]
Nature of the business [Abstract]
Ownership interest				41.47%
Share price (in dollars per share) \| $ / shares		$ 31
Proceeds from issuing shares		$ 327,980
Number of concessional assets contributed \| ConcessionalAsset					10
Interest consideration transferred					64.28%
Cash consideration transferred					$ 655,300
Cash retained for liquidity purposes					$ 30,000

Nature of the business, Assets acquired (Details)
$ in Thousands

12 Months Ended

Jul. 20, 2017

USD ($)

Feb. 28, 2017

Jan. 07, 2016

USD ($)

Dec. 31, 2017

Dec. 31, 2016

Aug. 03, 2016

USD ($)

Jul. 30, 2015

Length of transmission lines | mi

12.50%

114

Peru [Member]

Acquisition purchase price

Gross capacity | MW

$ 9,000

Honaine [Member]

^[1]

25.50%

Skikda [Member]

^[2]

34.20%

Helioenergy 1/2 [Member]

100.00%

Helios 1/2 [Member]

100.00%

Solnova 1/3/4 [Member]

100.00%

Kaxu [Member]

51.00%

^[3]

51.00%

Solaben 1/6 [Member]

100.00%

Solacor 1/2 [Member]

Acquisition purchase price

13.00%

$ 19,923

^[4]

87.00%

Seville PV [Member]

Acquisition purchase price

80.00%

Gross capacity | MW

$ 3,214

JGC [Member] | Solacor 1/2 [Member]

^[5]

80.00%

13.00%

[1]	Algerian Energy Company, SPA owns 49% of Honaine and Valoriza Agua, S.L. owns the remaining 25.5%.
[2]	Algerian Energy Company, SPA owns 49% of Skikda and Valoriza Agua, S.L. owns the remaining 16.83%.
[3]	Kaxu is owned by the Company (51%), Industrial Development Corporation of South Africa (29%) and Kaxu Community Trust (20%).
[4]	JGC, a Japanese engineering company, holds 13% of the shares in each of Solacor 1 and Solacor 2.
[5]	Instituto para la Diversificacion y Ahorro de la Energia ("Idae"), a Spanish state owned company, holds 20% of the shares in Seville PV.

Nature of the business, Concessional assets owned (Details) - USD ($)
$ in Thousands

12 Months Ended

Jan. 07, 2016

Sep. 30, 2013

Dec. 31, 2017

Dec. 31, 2016

ACT [Member]

Efficient natural gas

100.00%

Mexico

^[1]

USD

300 MW

^[2]

BBB+/A3/BBB+

^[3]

2Q 2013

^[4]

15 years

ATN [Member]

Transmission line

100.00%

Peru

^[1]

USD

362 miles

^[2]

BBB+/A3/BBB+

^[3]

1Q 2011

^[4]

23 years

ATS [Member]

Transmission line

100.00%

Peru

^[1]

USD

569 miles

^[2]

BBB+/A3/BBB+

^[3]

1Q 2014

^[4]

26 years

ATN2 [Member]

Transmission line

100.00%

Peru

^[1]

USD

81 miles

^[2]

Not rated

^[3]

2Q 2015

^[4]

15 years

Quadra 1 [Member]

Transmission line

100.00%

Chile

^[1]

USD

49 miles

^[2]

Not rated

^[3]

2Q 2014

^[4]

17 years

Quadra 2 [Member]

Transmission line

100.00%

Chile

^[1]

USD

32 miles

^[2]

Not rated

^[3]

1Q 2014

^[4]

17 years

Palmucho [Member]

Transmission line

100.00%

Chile

^[1]

USD

6 miles

^[2]

BBB+/Baa2/BBB+

^[3]

4Q 2007

^[4]

20 years

Skikda [Member]

Water

^[5]

34.20%

Algeria

^[1]

USD

3.5 M ft3/day

^[2]

Not rated

^[3]

1Q 2009

Skikda [Member] | Algerian Energy Company, SPA [Member]

^[4]

16 years

Skikda [Member] | Valoriza Agua, S.L. [Member]

49.00%

16.83%

Honaine [Member]

Water

^[6]

25.50%

Algeria

^[1]

USD

7 M ft3/day

^[2]

Not rated

^[3]

3Q 2012

Honaine [Member] | Algerian Energy Company, SPA [Member]

^[4]

20 years

Honaine [Member] | Valoriza Agua, S.L. [Member]

49.00%

25.50%

PS10/PS20 [Member]

Renewable (Solar)

100.00%

Spain

^[1]

Euro

31 MW

^[2]

BBB+/Baa2/A-

^[3]

1Q 2007 & 2Q 2009

PS10 [Member]

^[4]

14 years

PS20 [Member]

^[4]

16 years

Solana [Member]

Renewable (Solar)

100.00%

Ownership interest type

^[7]

Class B

Arizona (USA)

^[1]

USD

280 MW

^[2]

A-/A3/A-

^[3]

4Q 2013

Solana [Member] | Liberty Interactive Corporation [Member]

^[4]

26 years

Class A membership investment

$ 300,000

Percentage of dividends and taxable loss once certain conditions met

22.60%

Solana [Member] | Liberty Interactive Corporation [Member] | Bottom of Range [Member]

Percentage of dividends and taxable loss received

54.06%

Solana [Member] | Liberty Interactive Corporation [Member] | Top of Range [Member]

Percentage of dividends and taxable loss received

61.20%

Mojave [Member]

Renewable (Solar)

100.00%

California (USA)

^[1]

USD

280 MW

^[2]

A-/A3/A-

^[3]

4Q 2014

^[4]

22 years

Solaben 2 & 3 [Member]

Renewable (Solar)

^[8]

70.00%

Spain

^[1]

Euro

2x50 MW

^[2]

BBB+/Baa2/A-

Solaben 2 & 3 [Member] | Itochu Corporation [Member]

^[3]

3Q 2012 & 2Q 2012

30.00%

Solaben 2 [Member]

^[4]

20 years

Solaben 3 [Member]

^[4]

19 years

Solacor 1 & 2 [Member]

Renewable (Solar)

^[9]

87.00%

Spain

^[1]

Euro

2x50 MW

^[2]

BBB+/Baa2/A-

^[3]

1Q 2012 & 1Q 2012

Solacor 1 & 2 [Member] | JGC [Member]

^[4]

19 years

13.00%

Helioenergy 1 & 2 [Member]

13.00%

Renewable (Solar)

100.00%

Spain

^[1]

Euro

2x50 MW

^[2]

BBB+/Baa2/A-

^[3]

3Q 2011 & 4Q 2011

^[4]

19 years

Helios 1 & 2 [Member]

Renewable (Solar)

100.00%

Spain

^[1]

Euro

2x50 MW

^[2]

BBB+/Baa2/A-

^[3]

3Q 2012 & 3Q 2012

Solnova 1, 3 & 4 [Member]

^[4]

20 years

Renewable (Solar)

100.00%

Spain

^[1]

Euro

3x50 MW

^[2]

BBB+/Baa2/A-

^[3]

2Q 2010 & 2Q 2010 & 3Q 2010

Solnova 1 [Member]

^[4]

17 years

Solnova 3 [Member]

^[4]

17 years

Solnova 4 [Member]

^[4]

18 years

Solaben 1 & 6 [Member]

Renewable (Solar)

100.00%

Spain

^[1]

Euro

2x50 MW

^[2]

BBB+/Baa2/A-

^[3]

3Q 2013

^[4]

21 years

Kaxu [Member]

Renewable (Solar)

^[10]

51.00%

South Africa

^[1]

Rand

100 MW

^[2],[11]

BB/Baa3/BB+

^[3]

1Q 2015

Kaxu [Member] | IDC [Member]

^[4]

17 years

Kaxu [Member] | Kaxu Community Trust [Member]

29.00%

20.00%

Palmatir [Member]

Renewable (Wind)

100.00%

Uruguay

^[1]

USD

50 MW

^[2],[12]

BBB/Baa2/BBB-

^[3]

2Q 2014

^[4]

16 years

Cadonal [Member]

Renewable (Wind)

100.00%

Uruguay

^[1]

USD

50 MW

^[2],[12]

BBB/Baa2/BBB-

^[3]

4Q 2014

^[4]

17 years

Seville PV [Member]

Renewable (Solar)

^[13]

80.00%

Spain

^[1]

Euro

1 MW

^[2]

BBB+/Baa2/A-

^[3]

3Q 2006

Seville PV [Member] | Idae [Member]

^[4]

18 years

Changes in the scope of the consolidated financial statements [Abstract]

20.00%

[1]	Certain contracts denominated in U.S. dollars are payable in local currency.
[2]	Reflects the counterparty's credit ratings issued by Standard & Poor's Ratings Services, or S&P, Moody's Investors Service Inc., or Moody's, and Fitch Ratings Ltd, or Fitch.
[3]	Commercial Operation Date ("COD").
[4]	As of December 31, 2017.
[5]	Algerian Energy Company, SPA owns 49% of Skikda and Valoriza Agua, S.L. owns the remaining 16.83%.
[6]	Algerian Energy Company, SPA owns 49% of Honaine and Valoriza Agua, S.L. owns the remaining 25.5%.
[7]	On September 30, 2013, Liberty Interactive Corporation invested $300,000 thousand in Class A membership interests in exchange for a share of the dividends and taxable loss generated by Solana. As a result of the agreement, Liberty Interactive Corporation will receive between 54.06% and 61.20% of both dividends and taxable loss generated during a period of approximately five years; such percentage will decrease to 22.60% thereafter.
[8]	Itochu Corporation, a Japanese trading company, holds 30% of the shares in each of Solaben 2 and Solaben 3.
[9]	JGC, a Japanese engineering company, holds 13% of the shares in each of Solacor 1 and Solacor 2.
[10]	Kaxu is owned by the Company (51%), Industrial Development Corporation of South Africa (29%) and Kaxu Community Trust (20%).
[11]	Refers to the credit rating of the Republic of South Africa. The offtaker is Eskom, which is a state-owned utility company in South Africa.
[12]	Refers to the credit rating of Uruguay, as UTE (Administracion Nacional de Usinas y Transmisoras Electricas) is unrated.
[13]	Instituto para la Diversificacion y Ahorro de la Energia ("Idae"), a Spanish state owned company, holds 20% of the shares in Seville PV.

Nature of the business, Financing arrangements (Details) € in Millions, $ in Millions		1 Months Ended	12 Months Ended
	Nov. 01, 2017	Nov. 30, 2017	Dec. 31, 2017	Dec. 31, 2016	Feb. 10, 2017 USD ($)	Feb. 10, 2017 EUR (€)	Feb. 03, 2017
Note Issuance Facility [Member]
Financing arrangements [Abstract]
Principal amount					$ 330	€ 275
Abengoa [Member]
Financing arrangements [Abstract]
Percentage of financial liabilities approved							94.00%
Minimum ownership requirement percentage		30.00%		35.00%
Ownership interest			41.47%
Percentage of outstanding shares pledged as collateral			41.44%
Stake in parent to be sold to Algonquin	25.00%
Remaining ownership percentage	16.50%
Abengoa [Member] \| Solana and Mojave [Member]
Financing arrangements [Abstract]
Minimum ownership requirement percentage		16.00%	30.00%

Significant accounting policies, Asset impairment (Details)	Dec. 31, 2017
EMEA [Member]
Cash-generating units [Abstract]
Growth rate	0.00%
EMEA [Member] \| Bottom of Range [Member]
Cash-generating units [Abstract]
Discount rate	4.00%
EMEA [Member] \| Top of Range [Member]
Cash-generating units [Abstract]
Discount rate	6.00%
North America [Member]
Cash-generating units [Abstract]
Growth rate	0.00%
North America [Member] \| Bottom of Range [Member]
Cash-generating units [Abstract]
Discount rate	4.00%
North America [Member] \| Top of Range [Member]
Cash-generating units [Abstract]
Discount rate	6.00%
South America [Member]
Cash-generating units [Abstract]
Growth rate	0.00%
South America [Member] \| Bottom of Range [Member]
Cash-generating units [Abstract]
Discount rate	5.00%
South America [Member] \| Top of Range [Member]
Cash-generating units [Abstract]
Discount rate	7.00%

Financial risk management (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Interest Rate Risk [Member]
Financial risk management [Abstract]
Forecasted increase in benchmark interest rate	0.25%
Forecasted loss on cash flow hedges due to increase in benchmark interest rate	$ (228)	$ (2,563)	$ (1,795)
Forecasted increase in hedging reserves due to increase in benchmark interest rate	$ 37,767	$ 37,290	$ 41,702
Interest Rate Risk [Member] \| Euros [Member]
Financial risk management [Abstract]
Maturity date	2030
Interest Rate Risk [Member] \| Euros [Member] \| Bottom of Range [Member]
Financial risk management [Abstract]
Percentage of notional amount of debt hedged	87.00%
Interest rate	3.20%
Interest Rate Risk [Member] \| Euros [Member] \| Top of Range [Member]
Financial risk management [Abstract]
Percentage of notional amount of debt hedged	100.00%
Interest rate	4.87%
Interest Rate Risk [Member] \| U.S. Dollars [Member]
Financial risk management [Abstract]
Maturity date	2032
Interest Rate Risk [Member] \| U.S. Dollars [Member] \| Bottom of Range [Member]
Financial risk management [Abstract]
Percentage of notional amount of debt hedged	70.00%
Interest rate	2.32%
Interest Rate Risk [Member] \| U.S. Dollars [Member] \| Top of Range [Member]
Financial risk management [Abstract]
Percentage of notional amount of debt hedged	100.00%
Interest rate	5.27%
Currency Risk [Member]
Financial risk management [Abstract]
Net Euro exposure percentage for next fiscal year	100.00%
Net Euro exposure percentage for following fiscal period	75.00%

Financial information by segment, Business sectors (Details) ft³ / d in Millions			12 Months Ended
	Jul. 20, 2017 MW	Feb. 28, 2017 mi	Dec. 31, 2017 ft³ / d WindFarm Plant Line SolarPlatform mi MW	Dec. 31, 2016 MW
Financial information by segment [Abstract]
Length of transmission lines \| mi		114
Seville PV [Member]
Financial information by segment [Abstract]
Gross capacity				1
United States [Member] \| Renewable Energy [Member] \| Solana [Member]
Financial information by segment [Abstract]
Number of contracted assets \| Plant			1
Gross capacity			280
United States [Member] \| Renewable Energy [Member] \| Mojave [Member]
Financial information by segment [Abstract]
Number of contracted assets \| Plant			1
Gross capacity			280
Spain [Member] \| Renewable Energy [Member]
Financial information by segment [Abstract]
Number of contracted assets \| SolarPlatform			8
Spain [Member] \| Renewable Energy [Member] \| PS10/PS20 [Member]
Financial information by segment [Abstract]
Gross capacity			31
Spain [Member] \| Renewable Energy [Member] \| Solacor 1 and Solacor 2 [Member]
Financial information by segment [Abstract]
Gross capacity			100
Spain [Member] \| Renewable Energy [Member] \| Solaben 2 and 3 [Member]
Financial information by segment [Abstract]
Gross capacity			100
Spain [Member] \| Renewable Energy [Member] \| Helioenergy 1 and 2 [Member]
Financial information by segment [Abstract]
Gross capacity			100
Spain [Member] \| Renewable Energy [Member] \| Helios 1 and 2 [Member]
Financial information by segment [Abstract]
Gross capacity			100
Spain [Member] \| Renewable Energy [Member] \| Solnova 1, 3 and 4 [Member]
Financial information by segment [Abstract]
Gross capacity			150
Spain [Member] \| Renewable Energy [Member] \| Solaben 1 and 6 [Member]
Financial information by segment [Abstract]
Gross capacity			100
Spain [Member] \| Renewable Energy [Member] \| Seville PV [Member]
Financial information by segment [Abstract]
Gross capacity			1
South Africa [Member] \| Renewable Energy [Member] \| Kaxu [Member]
Financial information by segment [Abstract]
Number of contracted assets \| Plant			1
Gross capacity			100
Uruguay [Member] \| Renewable Energy [Member] \| Palmatir [Member]
Financial information by segment [Abstract]
Number of contracted assets \| WindFarm			1
Gross capacity			50
Uruguay [Member] \| Renewable Energy [Member] \| Cadonal [Member]
Financial information by segment [Abstract]
Number of contracted assets \| WindFarm			1
Gross capacity			50
Mexico [Member] \| Efficient Natural Gas [Member] \| ACT [Member]
Financial information by segment [Abstract]
Gross capacity			300
Term of take-or-pay contract			20 years
Peru [Member]
Financial information by segment [Abstract]
Gross capacity	4
Peru [Member] \| Electric Transmission [Member] \| ATN, ATS and ATN2 [Member]
Financial information by segment [Abstract]
Number of contracted assets \| Line			3
Length of transmission lines \| mi			1,012
Chile [Member] \| Electric Transmission [Member] \| Quadra 1, Quadra 2, and Palmucho [Member]
Financial information by segment [Abstract]
Number of contracted assets \| Line			3
Length of transmission lines \| mi			87
Algeria [Member] \| Water [Member] \| Honaine and Skikda [Member]
Financial information by segment [Abstract]
Number of contracted assets \| Plant			2
Aggregate capacity \| ft³ / d			10.5

Financial information by segment, Revenues and Further Adjusted EBITDA (Details) $ in Thousands	12 Months Ended
	Dec. 31, 2017 USD ($) Customer	Dec. 31, 2016 USD ($) Customer	Dec. 31, 2015 USD ($)
Financial information by segment [Abstract]
Number of customers representing more than 10% of total revenues \| Customer	3	3
Revenue	$ 1,008,381	$ 971,797	$ 790,881
Further Adjusted EBITDA	$ 779,310	$ 763,310	624,218
Renewable Energy [Member]
Financial information by segment [Abstract]
Number of customers representing more than 10% of total revenues \| Customer	2	2
Revenue	$ 767,226	$ 724,325	543,012
Further Adjusted EBITDA	$ 569,193	$ 538,427	413,933
Efficient Natural Gas [Member]
Financial information by segment [Abstract]
Number of customers representing more than 10% of total revenues \| Customer	1	1
Revenue	$ 119,784	$ 128,046	138,717
Further Adjusted EBITDA	106,140	106,492	107,671
Electric Transmission [Member]
Financial information by segment [Abstract]
Revenue	95,096	95,137	86,393
Further Adjusted EBITDA	87,695	104,795	89,047
Water [Member]
Financial information by segment [Abstract]
Revenue	26,275	24,288	22,759
Further Adjusted EBITDA	16,282	13,596	13,567
North America [Member]
Financial information by segment [Abstract]
Revenue	332,705	337,061	328,139
Further Adjusted EBITDA	282,328	284,691	279,559
South America [Member]
Financial information by segment [Abstract]
Revenue	120,797	118,764	112,480
Further Adjusted EBITDA	108,766	124,599	110,905
EMEA [Member]
Financial information by segment [Abstract]
Revenue	554,879	515,972	350,262
Further Adjusted EBITDA	$ 388,216	$ 354,020	$ 233,754

Financial information by segment, Reconciliation of segment Further Adjusted EBITDA (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Financial information by segment [Abstract]
Loss attributable to the Company	$ (111,804)	$ (4,855)	$ (209,005)
Profit attributable to non-controlling interests	(6,917)	(6,522)	(10,819)
Income tax	119,837	1,666	23,790
Share of profits/(losses) of associates	5,351	6,646	7,844
Dividend from exchangeable preferred equity investment in ACBH (Note 21)	10,383	27,948	18,400
Financial expense, net	448,368	405,750	526,758
Depreciation, amortization, and impairment charges	310,960	332,925	261,301
Total segment Further Adjusted EBITDA	779,310	763,310	624,218
Reconciling Item [Member]
Financial information by segment [Abstract]
Profit attributable to non-controlling interests	6,917	6,522	10,819
Income tax	119,837	1,666	23,790
Share of profits/(losses) of associates	(5,351)	(6,646)	(7,844)
Dividend from exchangeable preferred equity investment in ACBH (Note 21)	10,383	27,948	18,400
Financial expense, net	448,368	405,750	526,758
Depreciation, amortization, and impairment charges	310,960	332,925	261,301
Allocated [Member]
Financial information by segment [Abstract]
Total segment Further Adjusted EBITDA	$ 779,310	$ 763,310	$ 624,219

Financial information by segment, Assets and liabilities by geography (Details) - USD ($) $ in Thousands	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Assets [Abstract]
Contracted concessional assets	$ 9,084,270	$ 8,924,272
Investments carried under the equity method	55,784	55,009	$ 56,181
Current financial investments	210,138	228,038
Cash and cash equivalents (project companies)	669,387	594,811	514,712	$ 354,154
Total assets	10,492,339	10,297,799
Liabilities [Abstract]
Long-term and short-term project debt	5,475,208	5,330,467	5,470,669
Grants and other liabilities	1,636,060	1,612,045
Long-term and short-term corporate debt	643,083	668,201
Total liabilities	8,596,886	8,338,688
Equity	1,895,453	1,959,111	$ 2,023,501	$ 1,839,631
Total liabilities and equity	10,492,339	10,297,799
North America [Member]
Assets [Abstract]
Contracted concessional assets	3,770,169	3,920,106
Investments carried under the equity method	0	0
Current financial investments	116,451	136,665
Cash and cash equivalents (project companies)	149,236	185,970
Total assets	4,035,856	4,242,741
Liabilities [Abstract]
Long-term and short-term project debt	1,821,102	1,870,861
Grants and other liabilities	1,593,048	1,575,303
Total liabilities	3,414,150	3,446,164
South America [Member]
Assets [Abstract]
Contracted concessional assets	1,100,778	1,144,712
Investments carried under the equity method	0	0
Current financial investments	59,831	62,215
Cash and cash equivalents (project companies)	42,548	40,015
Total assets	1,203,157	1,246,942
Liabilities [Abstract]
Long-term and short-term project debt	876,063	895,316
Grants and other liabilities	810	1,512
Total liabilities	876,873	896,828
EMEA [Member]
Assets [Abstract]
Contracted concessional assets	4,213,323	3,859,454
Investments carried under the equity method	55,784	55,009
Current financial investments	31,263	29,158
Cash and cash equivalents (project companies)	329,078	246,671
Total assets	4,629,448	4,190,291
Liabilities [Abstract]
Long-term and short-term project debt	2,778,043	2,564,290
Grants and other liabilities	42,202	35,230
Total liabilities	2,820,245	2,599,520
Allocated [Member]
Assets [Abstract]
Contracted concessional assets	9,084,270	8,924,272
Investments carried under the equity method	55,784	55,009
Current financial investments	207,545	228,038
Cash and cash equivalents (project companies)	520,862	472,656
Total assets	9,868,461	9,679,975
Liabilities [Abstract]
Long-term and short-term project debt	5,475,208	5,330,467
Grants and other liabilities	1,636,060	1,612,045
Total liabilities	7,111,268	6,942,512
Unallocated [Member]
Assets [Abstract]
Other non-current assets	210,378	272,664
Other current assets (including cash and cash equivalents at holding company level)	413,500	345,160
Total assets	623,878	617,824
Liabilities [Abstract]
Long-term and short-term corporate debt	643,083	668,201
Other non-current liabilities	657,345	546,053
Other current liabilities	185,190	181,922
Total liabilities	1,485,618	1,396,176
Equity	1,895,453	1,959,111
Total liabilities and equity	$ 3,381,071	$ 3,355,287

Financial information by segment, Assets and liabilities by business sectors (Details) - USD ($) $ in Thousands	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Assets [Abstract]
Contracted concessional assets	$ 9,084,270	$ 8,924,272
Investments carried under the equity method	55,784	55,009	$ 56,181
Current financial investments	210,138	228,038
Cash and cash equivalents (project companies)	669,387	594,811	514,712	$ 354,154
Total assets	10,492,339	10,297,799
Liabilities [Abstract]
Long-term and short-term project debt	5,475,208	5,330,467	5,470,669
Grants and other liabilities	1,636,060	1,612,045
Long-term and short-term corporate debt	643,083	668,201
Total liabilities	8,596,886	8,338,688
Equity	1,895,453	1,959,111	$ 2,023,501	$ 1,839,631
Total liabilities and equity	10,492,339	10,297,799
Renewable Energy [Member]
Assets [Abstract]
Contracted concessional assets	7,436,362	7,255,308
Investments carried under the equity method	12,419	12,953
Current financial investments	17,249	13,661
Cash and cash equivalents (project companies)	452,792	420,215
Total assets	7,918,822	7,702,137
Liabilities [Abstract]
Long-term and short-term project debt	4,162,596	3,979,096
Grants and other liabilities	1,635,508	1,611,067
Total liabilities	5,798,104	5,590,163
Efficient Natural Gas [Member]
Assets [Abstract]
Contracted concessional assets	660,387	646,927
Investments carried under the equity method	0	0
Current financial investments	116,430	136,644
Cash and cash equivalents (project companies)	39,064	30,295
Total assets	815,881	813,866
Liabilities [Abstract]
Long-term and short-term project debt	579,173	598,256
Grants and other liabilities	552	239
Total liabilities	579,725	598,495
Electric Transmission [Member]
Assets [Abstract]
Contracted concessional assets	897,269	929,005
Investments carried under the equity method	0	0
Current financial investments	59,289	62,215
Cash and cash equivalents (project companies)	15,325	11,357
Total assets	971,883	1,002,577
Liabilities [Abstract]
Long-term and short-term project debt	698,346	711,517
Grants and other liabilities	0	739
Total liabilities	698,346	712,256
Water [Member]
Assets [Abstract]
Contracted concessional assets	90,252	93,032
Investments carried under the equity method	43,365	42,056
Current financial investments	14,577	15,518
Cash and cash equivalents (project companies)	13,681	10,789
Total assets	161,875	161,395
Liabilities [Abstract]
Long-term and short-term project debt	35,093	41,598
Grants and other liabilities	0	0
Total liabilities	35,093	41,598
Allocated [Member]
Assets [Abstract]
Contracted concessional assets	9,084,270	8,924,272
Investments carried under the equity method	55,784	55,009
Current financial investments	207,545	228,038
Cash and cash equivalents (project companies)	520,862	472,656
Total assets	9,868,461	9,679,975
Liabilities [Abstract]
Long-term and short-term project debt	5,475,208	5,330,467
Grants and other liabilities	1,636,060	1,612,045
Total liabilities	7,111,268	6,942,512
Unallocated [Member]
Assets [Abstract]
Other non-current assets	210,378	272,664
Other current assets (including cash and cash equivalents at holding company level)	413,500	345,160
Total assets	623,878	617,824
Liabilities [Abstract]
Long-term and short-term corporate debt	643,083	668,201
Other non-current liabilities	657,345	546,053
Other current liabilities	185,190	181,922
Total liabilities	1,485,618	1,396,176
Equity	1,895,453	1,959,111
Total liabilities and equity	$ 3,381,071	$ 3,355,287

Financial information by segment, Depreciation, amortization and impairment charges recognized (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Financial information by segment [Abstract]
Depreciation, amortization, and impairment charges	$ (310,960)	$ (332,925)	$ (261,301)
Renewable Energy [Member]
Financial information by segment [Abstract]
Depreciation, amortization, and impairment charges	(282,376)	(304,235)	(232,699)
Electric Transmission [Member]
Financial information by segment [Abstract]
Depreciation, amortization, and impairment charges	(28,584)	(28,690)	(28,602)
North America [Member]
Financial information by segment [Abstract]
Depreciation, amortization, and impairment charges	(123,726)	(129,478)	(129,091)
South America [Member]
Financial information by segment [Abstract]
Depreciation, amortization, and impairment charges	(40,880)	(62,387)	(41,274)
EMEA [Member]
Financial information by segment [Abstract]
Depreciation, amortization, and impairment charges	$ (146,354)	$ (141,060)	$ (90,936)

Changes in the scope of the consolidated financial statements, Changes (Details) - USD ($)
$ in Thousands

12 Months Ended

Jan. 07, 2016

Dec. 31, 2017

Dec. 31, 2016

Feb. 28, 2017

Aug. 03, 2016

Changes in the scope of the consolidated financial statements [Abstract]

12.50%

Solacor 1/2 [Member]

13.00%

Changes in the scope of the consolidated financial statements [Abstract]

^[1]

87.00%

Purchase price

$ 19,923

Seville PV [Member]

80.00%

JGC [Member] | Solacor 1/2 [Member]

^[2]

80.00%

Purchase price

$ 3,214

Changes in the scope of the consolidated financial statements [Abstract]

13.00%

[1]	JGC, a Japanese engineering company, holds 13% of the shares in each of Solacor 1 and Solacor 2.
[2]	Instituto para la Diversificacion y Ahorro de la Energia ("Idae"), a Spanish state owned company, holds 20% of the shares in Seville PV.

Contracted concessional assets (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016
Movements of Contracted Concessional Assets [Abstract]
Contracted concessional financial assets	$ 1,169,216	$ 1,100,243
Total, beginning of period	8,924,272
Total, end of period	9,084,270	8,924,272
Cost [Member]
Movements of Contracted Concessional Assets [Abstract]
Total, beginning of period	10,067,596	10,126,023
Additions	15,426	6,346
Subtractions	(42,500)
Translation differences	593,247	(68,199)
Change in the scope of the consolidated financial statements		5,876
Reclassification and other movements		(2,450)
Total, end of period	10,633,769	10,067,596
Accumulated Amortization [Member]
Movements of Contracted Concessional Assets [Abstract]
Total, beginning of period	(1,143,324)	(825,126)
Additions	(309,846)	(332,925)
Translation differences	(96,329)	17,108
Change in the scope of the consolidated financial statements		(2,381)
Total, end of period	(1,549,499)	(1,143,324)
Contracted Concessional Assets [Member]
Movements of Contracted Concessional Assets [Abstract]
Contracted concessional financial assets	936,004	$ 928,720
Impairment loss	$ 0
Palmatir and Cadonal [Member]
Movements of Contracted Concessional Assets [Abstract]
Assumed percentage decrease in generation		5.00%
Assumed percentage increase in discount rate		0.50%
Palmatir and Cadonal [Member] \| Bottom of Range [Member]
Movements of Contracted Concessional Assets [Abstract]
Discount rate		6.70%
Palmatir and Cadonal [Member] \| Top of Range [Member]
Movements of Contracted Concessional Assets [Abstract]
Discount rate		7.00%
Cadonal [Member]
Movements of Contracted Concessional Assets [Abstract]
Impairment loss		$ 17,299
Recoverable amount of impairment loss		91,795
Additional impairment loss that could be recognised due to assumed percentage decrease in generation		5,000
Additional impairment loss that could be recognised due to assumed increase in discount rate		3,000
Palmatir [Member]
Movements of Contracted Concessional Assets [Abstract]
Impairment loss		3,101
Recoverable amount of impairment loss		123,912
Additional impairment loss that could be recognised due to assumed percentage decrease in generation		7,000
Additional impairment loss that could be recognised due to assumed increase in discount rate		$ 4,000
Solana [Member]
Movements of Contracted Concessional Assets [Abstract]
Assumed percentage decrease in generation	5.00%	5.00%
Additional impairment loss that could be recognised due to assumed percentage decrease in generation		$ 40,000
Assumed percentage increase in discount rate	0.50%	0.50%
Additional impairment loss that could be recognised due to assumed increase in discount rate		$ 30,000
Percentage recoverable amount exceeds carrying amount	7.00%	3.00%
Solana [Member] \| Bottom of Range [Member]
Movements of Contracted Concessional Assets [Abstract]
Discount rate	4.70%	4.10%
Solana [Member] \| Top of Range [Member]
Movements of Contracted Concessional Assets [Abstract]
Discount rate	5.00%	5.10%

Investments carried under the equity method, Movement of the investments held in associates (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016
Investments in associates [Abstract]
Initial balance	$ 55,009	$ 56,181
Share of (loss)/profit	5,351	6,646
Dividend distribution	(2,454)	(3,954)
Equity distribution	(549)	(3,099)
Currency translation differences	(1,573)	(765)
Final balance	$ 55,784	$ 55,009

Investments carried under the equity method, Breakdown of stand-alone amounts (Details) - USD ($)
$ in Thousands

12 Months Ended

Dec. 31, 2017

Dec. 31, 2016

Dec. 31, 2015

$ 9,350,432

$ 9,251,945

1,141,907

1,045,854

8,096,498

7,163,622

500,388

1,175,066

1,008,381

971,797

$ 790,881

(104,887)

1,667

(198,186)

Evacuacion Valdecaballeros, S.L. [Member]

55,784

55,009

$ 56,181

Share of profit

$ 5,351

$ 6,646

57.16%

$ 21,306

$ 19,283

841

931

373

306

451

532

298

537

(708)

(545)

(730)

(565)

Evacuacion Valdecaballeros, S.L. [Member] | Bottom of Range [Member]

$ 9,175

$ 9,528

Percentage of shareholders required for approval of relevant decisions

75.00%

Myah Bahr Honaine, S.P.A. [Member]

^[1]

25.50%

^[1]

$ 195,275

$ 202,150

^[1]

64,114

67,120

^[1]

91,205

104,704

^[1]

12,649

14,158

^[1]

46,767

52,770

^[1]

28,468

34,247

^[1]

24,464

29,990

Myah Bahr Honaine, S.P.A. [Member] | Geida Tlemcen, S.L. [Member]

^[1]

$ 43,365

42,056

Pectonex, R.F. Proprietary Limited [Member]

51.00%

Share of profit

$ 6,238

$ 7,647

50.00%

$ 3,904

$ 3,730

(206)

(187)

(206)

(187)

Evacuacion Villanueva del Rey, S.L [Member]

$ 3,244

$ 3,425

40.02%

$ 3,526

$ 3,251

2,265

2,118

190

142

Associate Companies [Member]

240,011

228,684

65,008

68,068

93,843

107,128

13,292

14,833

47,065

53,307

27,591

33,546

23,528

29,238

Bank Bond and Surety Insurance deposited as guarantee

$ 55,784

$ 55,009

[1]

Myah Bahr Honaine, S.P.A., the project entity, is 51% owned by Geida Tlemcen, S.L. which is accounted for using the equity method in these consolidated financial statements. Share of profit of Myah Bahr Honaine S.P.A. included in these consolidated financial statements amounts to $6,238 thousand in 2017 and $7,647 thousand in 2016.

Financial instruments by category, Reconciliation to statement of financial position (Details) - USD ($) $ in Thousands	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Financial Assets [Abstract]
Derivative assets	$ 8,230	$ 3,822
Investment in Ten West Link	2,088
Abengoa debt and Equity instruments	1,715
Preferred equity in ACBH		30,488
Other financial investments	243,347	263,501
Clients and other receivables	244,449	207,621
Cash and cash equivalents	669,387	594,811	$ 514,712	$ 354,154
Total financial assets	1,169,216	1,100,243
Financial Liabilities [Abstract]
Corporate debt	643,083	668,201
Project debt	5,475,208	5,330,467	$ 5,470,669
Related parties - non-current	141,031	101,750
Trade and other current liabilities	155,144	160,505
Derivative liabilities	329,731	349,266
Total financial liabilities	6,744,197	6,610,189
Hedging Derivatives [Member]
Financial Liabilities [Abstract]
Corporate debt	0	0
Project debt	0	0
Related parties - non-current	0	0
Trade and other current liabilities	0	0
Derivative liabilities	329,731	349,266
Total financial liabilities	329,731	349,266
Hedging Derivatives [Member]
Financial Assets [Abstract]
Derivative assets	8,230	3,822
Investment in Ten West Link	0
Abengoa debt and Equity instruments	0
Preferred equity in ACBH		0
Other financial investments	0	0
Clients and other receivables	0	0
Cash and cash equivalents	0	0
Total financial assets	8,230	3,822
Payables [Member]
Financial Liabilities [Abstract]
Corporate debt	643,083	668,201
Project debt	5,475,208	5,330,467
Related parties - non-current	141,031	101,750
Trade and other current liabilities	155,144	160,505
Derivative liabilities	0	0
Total financial liabilities	6,414,466	6,260,923
Loans and Receivables [Member]
Financial Assets [Abstract]
Derivative assets	0	0
Investment in Ten West Link	2,088
Abengoa debt and Equity instruments	0
Preferred equity in ACBH		0
Other financial investments	243,347	263,501
Clients and other receivables	244,449	207,621
Cash and cash equivalents	669,387	594,811
Total financial assets	1,159,271	1,065,933
Available for Sale Financial Assets [Member]
Financial Assets [Abstract]
Derivative assets	0	0
Investment in Ten West Link	0
Abengoa debt and Equity instruments	1,715
Preferred equity in ACBH		30,488
Other financial investments	0	0
Clients and other receivables	0	0
Cash and cash equivalents	0	0
Total financial assets	$ 1,715	$ 30,488

Financial instruments by category, Restructuring agreement of Abengoa (Details) $ in Millions					1 Months Ended	12 Months Ended
	Mar. 31, 2017 USD ($)	Mar. 15, 2017 USD ($)	Feb. 28, 2017 mi	Feb. 24, 2017 USD ($)	Apr. 30, 2017 USD ($)	Dec. 31, 2017 USD ($) mi	Dec. 31, 2014
Restructuring agreement of Abengoa [Abstract]
Dividends retained from Abengoa				$ 10.4
Percentage interest acquired			12.50%
Length of transmission lines \| mi			114
New Money Tradable Notes [Member]
Restructuring agreement of Abengoa [Abstract]
Restructuring agreement assigned tradable notes amount	$ 44.5
Restructuring agreement cash contribution in exchange of tradable notes	$ 43.6
Ten West Link [Member]
Restructuring agreement of Abengoa [Abstract]
Percentage interest acquired						12.50%
Length of transmission lines \| mi						114
Abengoa [Member]
Restructuring agreement of Abengoa [Abstract]
Corporate tradable bonds issued period						5 years 6 months
Corporate tradable bonds issued extendable period						2 years
Corporate tradable bonds interest rate	1.50%
Corporate tradable bonds interest rate paid in cash	0.25%
Corporate tradable bonds interest rate paid in kind	1.25%
Loss from derecognition of fair value assigned to preferred equity investment and recognition of debt and equity instruments						$ 5.8
Profit resulting from sale of major part of debt and equity instruments						$ 6.5
Dividends retained from Abengoa		$ 10.4
Percentage interest acquired							64.28%
Abengoa [Member] \| New Money Tradable Notes [Member]
Restructuring agreement of Abengoa [Abstract]
Proceeds from sale of tradable notes					$ 44.9

Derivative financial instruments, Breakdown of fair value amounts (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016
Currency Swap [Member]
Breakdown of fair value amount of derivative financial instruments [Abstract]
Term of agreement	5 years
Interest Rate Derivatives [Member] \| Cash Flow Hedge [Member]
Breakdown of fair value amount of derivative financial instruments [Abstract]
Assets	$ 8,230	$ 3,822
Liabilities	$ 329,731	$ 349,266

Derivative financial instruments, Breakdown of maturities of notional and fair value amounts (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Breakdown of Maturities of Notional and Fair Value Amounts [Abstract]
Loss on cash flow hedges	$ 70,953	$ 72,774	$ 55,841
Cap [Member]
Breakdown of Maturities of Notional and Fair Value Amounts [Abstract]
Notionals	756,339	478,314
Fair value	$ 8,230	$ 3,822
Cap [Member] \| Up to 1 Year [Member]
Breakdown of Maturities of Notional and Fair Value Amounts [Abstract]
Notionals	42,324	24,261
Fair value	$ 347	$ 250
Cap [Member] \| Between 1 and 2 Years [Member]
Breakdown of Maturities of Notional and Fair Value Amounts [Abstract]
Notionals	45,422	25,934
Fair value	$ 978	$ 262
Cap [Member] \| Between 2 and 3 Years [Member]
Breakdown of Maturities of Notional and Fair Value Amounts [Abstract]
Notionals	48,215	27,880
Fair value	$ 396	$ 275
Cap [Member] \| Subsequent Years [Member]
Breakdown of Maturities of Notional and Fair Value Amounts [Abstract]
Notionals	620,378	400,239
Fair value	$ 6,509	$ 3,035
Swap [Member]
Breakdown of Maturities of Notional and Fair Value Amounts [Abstract]
Notionals	2,231,611	1,860,355
Fair value	$ (329,731)	$ (349,266)
Swap [Member] \| Up to 1 Year [Member]
Breakdown of Maturities of Notional and Fair Value Amounts [Abstract]
Notionals	139,939	75,837
Fair value	$ (13,224)	$ (12,383)
Swap [Member] \| Between 1 and 2 Years [Member]
Breakdown of Maturities of Notional and Fair Value Amounts [Abstract]
Notionals	94,285	199,832
Fair value	$ (14,378)	$ (14,927)
Swap [Member] \| Between 2 and 3 Years [Member]
Breakdown of Maturities of Notional and Fair Value Amounts [Abstract]
Notionals	103,536	83,897
Fair value	$ (15,923)	$ (13,957)
Swap [Member] \| Subsequent Years [Member]
Breakdown of Maturities of Notional and Fair Value Amounts [Abstract]
Notionals	1,893,850	1,500,789
Fair value	$ (286,206)	$ (307,999)
Interest Rate Derivatives [Member] \| Euros [Member]
Breakdown of Maturities of Notional and Fair Value Amounts [Abstract]
Maturity date	2030
Interest Rate Derivatives [Member] \| Euros [Member] \| Bottom of Range [Member]
Breakdown of Maturities of Notional and Fair Value Amounts [Abstract]
Percentage of notional amount of project debt hedged	87.00%
Average guaranteed interest rates	3.20%
Interest Rate Derivatives [Member] \| Euros [Member] \| Top of Range [Member]
Breakdown of Maturities of Notional and Fair Value Amounts [Abstract]
Percentage of notional amount of project debt hedged	100.00%
Average guaranteed interest rates	4.87%
Interest Rate Derivatives [Member] \| U.S. Dollars [Member]
Breakdown of Maturities of Notional and Fair Value Amounts [Abstract]
Maturity date	2032
Interest Rate Derivatives [Member] \| U.S. Dollars [Member] \| Bottom of Range [Member]
Breakdown of Maturities of Notional and Fair Value Amounts [Abstract]
Percentage of notional amount of project debt hedged	70.00%
Average guaranteed interest rates	2.32%
Interest Rate Derivatives [Member] \| U.S. Dollars [Member] \| Top of Range [Member]
Breakdown of Maturities of Notional and Fair Value Amounts [Abstract]
Percentage of notional amount of project debt hedged	100.00%
Average guaranteed interest rates	5.27%
Interest Rate Derivatives [Member] \| Cash Flow Hedge [Member]
Breakdown of Maturities of Notional and Fair Value Amounts [Abstract]
Loss on cash flow hedges	$ (70,953)	(72,774)	(55,841)
Gain (loss) on net amount of time value component	860	1,694	$ 4,234
After-tax result accumulated in equity	$ 80,968	$ 52,797

Related parties (Details) $ in Thousands, € in Millions			3 Months Ended	12 Months Ended
Related parties (Details) $ in Thousands, € in Millions	Nov. 30, 2017 USD ($)	Feb. 24, 2017 USD ($)	Sep. 30, 2017 EUR (€)	Dec. 31, 2017 USD ($)	Dec. 31, 2016 USD ($)	Dec. 31, 2015 USD ($)
Details of Balances [Abstract]
Current receivables with related parties				$ 11,567	$ 12,031
Non-current receivables with related parties				2,108	30,505
Current payables with related parties				63,409	61,338
Non-current payables with related parties				141,031	101,750
Receivables from related parties				1,715
Preferred equity in ACBH					30,488
Transactions With Related Party [Abstract]
Financial income				1,007	3,298	$ 3,464
Financial expenses				(463,717)	(408,007)	(333,921)
Dividends retained from Abengoa		$ 10,400
Related Parties [Member]
Details of Balances [Abstract]
Receivables from related parties				1,715
Preferred equity in ACBH					30,488
Transactions With Related Party [Abstract]
Dividends retained from Abengoa				10,400	28,000
Income for cancellation of subordinated debt					7,600
Income for discounts received for prepayment of payables					1,700
Subsidiaries [Member]
Transactions With Related Party [Abstract]
Sales				0	0	44,260
Services rendered				3,495	1,220	523
Services received				(114,416)	(115,779)	(106,737)
Financial income				74	60	1,466
Financial expenses				$ (1,154)	$ (2,460)	$ (1,968)
Abengoa [Member]
Transactions With Related Party [Abstract]
Term to maintain guarantees and letters of credit				5 years
Guarantees amount				$ 31,500
Other existing debts receivables \| €			€ 7.8
Guarantees amount replaced				$ 112,000
Abengoa [Member] \| Solana [Member]
Transactions With Related Party [Abstract]
Performance consideration receivable	$ 120,000
Performance obligations proceeds applied to project debt	80,000
Performance obligations proceeds applied to additional plant repairs	25,000
Other obligations	15,000
Other obligations per semester	6,500
Recognition period of other contingnt obligations considered				10 years
Performance obligations proceeds received from Abengoa	$ 42,500
Abengoa [Member] \| Solana and Mojave [Member]
Transactions With Related Party [Abstract]
Minimum ownership requirement percentage	16.00%

Clients and other receivable (Details) - USD ($) $ in Thousands	Dec. 31, 2017	Dec. 31, 2016
Clients and other receivables [Abstract]
Trade receivables	$ 186,728	$ 151,199
Tax receivables	39,607	29,705
Prepayments	6,375	10,261
Other accounts receivable	11,739	16,456
Clients and other receivables	244,449	207,621
Up to 3 Months [Member]
Clients and other receivables [Abstract]
Trade receivables	186,728	151,199
Euros [Member]
Clients and other receivables [Abstract]
Trade receivables	109,165	98,798
Rand [Member]
Clients and other receivables [Abstract]
Trade receivables	23,792	12,807
Other [Member]
Clients and other receivables [Abstract]
Trade receivables	7,363	7,151
All Foreign Currencies [Member]
Clients and other receivables [Abstract]
Trade receivables	$ 140,320	$ 118,756

Cash and cash equivalents (Details) - USD ($) $ in Thousands	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Cash and cash equivalents [abstract]
Cash and cash equivalents	$ 669,387	$ 594,811	$ 514,712	$ 354,154
Cash held to satisfy the requirements of non-recourse debt agreements	263,000
U.S. Dollar [Member]
Cash and cash equivalents [abstract]
Cash and cash equivalents	319,400	343,954
Euro [Member]
Cash and cash equivalents [abstract]
Cash and cash equivalents	288,625	196,382
Algerian Dinar [Member]
Cash and cash equivalents [abstract]
Cash and cash equivalents	13,628	10,736
South African Rand [Member]
Cash and cash equivalents [abstract]
Cash and cash equivalents	40,999	39,689
Others [Member]
Cash and cash equivalents [abstract]
Cash and cash equivalents	$ 6,735	$ 4,050

Equity (Details) $ / shares in Units, $ in Thousands											1 Months Ended	6 Months Ended	12 Months Ended	18 Months Ended
Equity (Details) $ / shares in Units, $ in Thousands	Nov. 13, 2017 $ / shares	Aug. 03, 2017 $ / shares	May 15, 2017 $ / shares	Mar. 15, 2017 USD ($)	Feb. 27, 2017 $ / shares	Feb. 24, 2017 USD ($)	Jul. 14, 2015 shares	May 14, 2015 $ / shares shares	Jan. 22, 2015 USD ($) $ / shares shares	Jun. 18, 2014 USD ($) $ / shares shares	Jan. 21, 2015	Jul. 13, 2015	Dec. 31, 2017 USD ($) Vote $ / shares shares	Dec. 31, 2016 USD ($)
Equity [Abstract]
Number of shares sold (in shares) \| shares								20,217,260		24,850,000
Share price (in dollars per share) \| $ / shares								$ 33.14		$ 29
Proceeds from issuing shares										$ 720,650
Share capital										2,485			$ 10,022	$ 10,022
Additional paid in capital										$ 682,810
Discount percentage applied to share price								3.00%
Shares outstanding (in shares) \| shares													100,217,260
Nominal value per share (in dollars per share) \| $ / shares													$ 0.10
Voting right per share \| Vote													1
Dividends retained from Abengoa						$ 10,400
Treasury shares held (in shares) \| shares													0
Increase (decrease) in treasury shares (in shares) \| shares													0
First Quarter [Member]
Equity [Abstract]
Dividend declared and paid (in dollars per share) \| $ / shares			$ 0.25
Second Quarter [Member]
Equity [Abstract]
Dividend declared and paid (in dollars per share) \| $ / shares		$ 0.26
Third Quarter [Member]
Equity [Abstract]
Dividend declared and paid (in dollars per share) \| $ / shares	$ 0.29
Fourth Quarter [Member]
Equity [Abstract]
Dividend declared and paid (in dollars per share) \| $ / shares					$ 0.25
Abengoa [Member]
Equity [Abstract]
Number of shares sold (in shares) \| shares							2,000,000		10,580,000
Share price (in dollars per share) \| $ / shares									$ 31
Proceeds from issuing shares									$ 327,980
Ownership interest											64.30%	51.10%		49.10%
Percent of newly-issued shares subscribed								51.00%
Dividends retained from Abengoa				$ 10,400
Exchangeable Notes [Member] \| Abengoa [Member]
Equity [Abstract]
Ownership interest													41.47%
Number of shares issued upon conversion of exchangeable notes (in shares) \| shares													7,595,639
Principal amount													$ 279,000
Subsidiary of Abengoa [Member]
Equity [Abstract]
Shares purchased by underwriters (in shares) \| shares										3,727,500
Total proceeds from offering										$ 828,748

Corporate debt, Breakdown of corporate debt (Details) $ in Thousands, € in Millions		12 Months Ended
	Feb. 10, 2017 USD ($) Swap	Dec. 31, 2017 USD ($)	Feb. 10, 2017 EUR (€)	Dec. 31, 2016 USD ($)
Corporate debt [Abstract]
Total Non-Current		$ 574,176		$ 376,340
Total Current		68,907		291,861
Credit Facilities with Financial Entities [Member]
Corporate debt [Abstract]
Total Non-Current		320,783		123,804
Total Current		65,833		289,035
Notes and Bonds [Member]
Corporate debt [Abstract]
Total Non-Current		253,393		252,536
Total Current		$ 3,074		$ 2,826
Note Issuance Facility [Member]
Corporate debt [Abstract]
Principal amount	$ 330,000		€ 275
Number of interest rate swaps \| Swap	2
Fixed interest rate	5.50%		5.50%
Note Issuance Facility [Member] \| EURIBOR [Member]
Corporate debt [Abstract]
Adjustment to interest rate	4.90%		4.90%
Series 1 Notes [Member]
Corporate debt [Abstract]
Maturity date		2022
Series 2 Notes [Member]
Corporate debt [Abstract]
Maturity date		2023
Series 3 Notes [Member]
Corporate debt [Abstract]
Maturity date		2024

Corporate debt, Details of corporate debt (Details) $ in Thousands, € in Millions				12 Months Ended
	Dec. 27, 2017 USD ($)	Sep. 25, 2017 USD ($)	Dec. 22, 2014 USD ($)	Dec. 31, 2017 USD ($)	Dec. 31, 2016 USD ($)	Dec. 31, 2015 USD ($)	Jul. 20, 2017 USD ($)	Jul. 20, 2017 EUR (€)	Jun. 26, 2015 USD ($)	Dec. 03, 2014 USD ($)	Nov. 17, 2014 USD ($)
Corporate debt [Abstract]
Proceeds from corporate debt				$ 296,398	$ 11,113	$ 459,366
Repayment of debt				613,242	182,636	175,389
Short-term corporate debt				68,907	291,861
Long-term corporate debt				$ 574,176	376,340
Federal Funds Rate [Member]
Corporate debt [Abstract]
Adjustment to interest rate									0.50%
LIBOR [Member]
Corporate debt [Abstract]
Adjustment to interest rate									1.00%
2019 Notes [Member]
Corporate debt [Abstract]
Principal amount											$ 255,000
Fixed interest rate											7.00%
Maturity date				November 15, 2019
Credit Facility Tranche A [Member]
Corporate debt [Abstract]
Fixed interest rate										4.70%
Maturity date				December 24, 2018
Proceeds from corporate debt			$ 125,000
Repayment of debt	$ 63,000	$ 8,000
Short-term corporate debt				$ 54,000
Long-term corporate debt					54,000
Credit Facility Tranche A [Member] \| Top of Range [Member]
Corporate debt [Abstract]
Principal amount										$ 125,000
Tranche A Eurodollar Rate Loans [Member] \| LIBOR [Member]
Corporate debt [Abstract]
Adjustment to interest rate										2.75%
Tranche A Base Rate Loans [Member]
Corporate debt [Abstract]
Adjustment to interest rate										1.75%
Tranche A Base Rate Loans [Member] \| Federal Funds Rate [Member]
Corporate debt [Abstract]
Adjustment to interest rate										0.50%
Tranche A Base Rate Loans [Member] \| LIBOR [Member]
Corporate debt [Abstract]
Adjustment to interest rate										1.00%
Credit Facility Tranche B [Member]
Corporate debt [Abstract]
Principal amount									$ 290,000
Maturity date				December 2017
Short-term corporate debt					$ 288,317
Long-term corporate debt						$ 288,317
Tranche B Eurodollar Rate Loans [Member] \| LIBOR [Member]
Corporate debt [Abstract]
Adjustment to interest rate									2.50%
Tranche B Base Rate Loans [Member] \| LIBOR [Member]
Corporate debt [Abstract]
Adjustment to interest rate									1.50%
Credit Facility 2017 [Member]
Corporate debt [Abstract]
Principal amount							$ 11,900
Maturity date				July 20, 2018
Credit Facility 2017 [Member] \| Top of Range [Member]
Corporate debt [Abstract]
Principal amount \| €								€ 10
Credit Facility 2017 [Member] \| EURIBOR [Member]
Corporate debt [Abstract]
Adjustment to interest rate							2.25%	2.25%
Credit Facility 2017 [Member] \| LIBOR [Member]
Corporate debt [Abstract]
Adjustment to interest rate							2.25%	2.25%

Corporate debt, Movement in corporate debt, split between cash and non-cash items (Details) $ in Thousands	12 Months Ended
	Dec. 31, 2017 USD ($)
Corporate debt [Abstract]
Beginning balance	$ 668,201
Cash flow	(68,372)
Non-cash changes	43,254
Ending balance	$ 643,083

Project debt, Movements of project debt (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016
Project Debt - Long Term [Abstract]
Beginning balance	$ 4,629,184	$ 3,574,464
Increases	52,027	36,842
Decreases	(42,560)	0
Currency translation differences	316,646	(64,426)
Reclassifications	273,620	1,082,304
Ending balance	5,228,917	4,629,184
Project Debt - Short Term [Abstract]
Beginning balance	701,283	1,896,205
Increases	304,707	329,434
Decreases	(509,131)	(480,969)
Currency translation differences	23,052	38,917
Reclassifications	(273,620)	(1,082,304)
Ending balance	246,291	701,283
Total Project Debt [Abstract]
Beginning balance	5,330,467	5,470,669
Increases	356,734	366,276
Decreases	(551,691)	(480,969)
Currency translation differences	339,698	(25,509)
Reclassifications	0	0
Ending balance	$ 5,475,208	$ 5,330,467

Project debt, Repayment schedule (Details) - USD ($) $ in Thousands	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Repayment schedule [Abstract]
Project debt	$ 5,475,208	$ 5,330,467	$ 5,470,669
2018 [Member]
Repayment schedule [Abstract]
Interest repayment	21,612
Nominal repayment	224,679
2019 [Member]
Repayment schedule [Abstract]
Project debt	246,471
2020 [Member]
Repayment schedule [Abstract]
Project debt	265,002
2021 [Member]
Repayment schedule [Abstract]
Project debt	280,303
2022 [Member]
Repayment schedule [Abstract]
Project debt	313,559
Subsequent Years [Member]
Repayment schedule [Abstract]
Project debt	$ 4,123,582

Project debt, movement in project debt, split between cash and non-cash items (Details) $ in Thousands	12 Months Ended
	Dec. 31, 2017 USD ($)
Project debt [Abstract]
Beginning balance	$ 5,330,467
Cash flow	(248,472)
Non-cash changes	393,212
Ending balance	$ 5,475,208

Project debt, Movement in project debt and Significant foreign currency denominated debts (Details) - USD ($) $ in Thousands	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Project Debt [Abstract]
Project debt	$ 5,475,208	$ 5,330,467	$ 5,470,669
Euro [Member]
Project Debt [Abstract]
Project debt	2,286,771	2,102,985
Algerian Dinar [Member]
Project Debt [Abstract]
Project debt	35,093	41,598
Rand [Member]
Project Debt [Abstract]
Project debt	456,179	419,708
All Foreign Currencies [Member]
Project Debt [Abstract]
Project debt	$ 2,778,043	$ 2,564,291

Grants and other liabilities (Details) $ in Thousands	12 Months Ended
Grants and other liabilities (Details) $ in Thousands	Dec. 31, 2017 USD ($) Type	Dec. 31, 2016 USD ($)	Dec. 31, 2015 USD ($)	Oct. 02, 2013 USD ($)
Grants and other liabilities [Abstract]
Grants	$ 1,225,877	$ 1,297,755
Number of grant types \| Type	2
Other liabilities	$ 410,183	314,290
Grant and other non-current liabilities	1,636,060	1,612,045
Income from grants	59,707	59,085	$ 67,859
Solana and Mojave [Member]
Grants and other liabilities [Abstract]
Income from grants	59,800	57,000
U.S. Department of Treasury [Member]
Grants and other liabilities [Abstract]
Grants	771,000	803,000
Federal Financing Bank [Member]
Grants and other liabilities [Abstract]
Grants	452,000	492,000
Liberty Interactive Corporation [Member]
Grants and other liabilities [Abstract]
Grant and other non-current liabilities	$ 352,000	$ 263,000
Class A membership investment				$ 300,000

Trade payables and other current liabilities (Details) - USD ($) $ in Thousands	Dec. 31, 2017	Dec. 31, 2016
Trade payables and other current liabilities [Abstract]
Trade accounts payables	$ 107,662	$ 121,527
Down payments from clients	6,466	6,153
Suppliers of concessional assets current	236	380
Liberty (see Note 16)	0	21,461
Other accounts payable	40,780	10,984
Total	$ 155,144	$ 160,505

Income Tax, Analysis of deferred tax assets and liabilities (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Deferred Tax Assets and Liabilities [Abstract]
Net operating losses		$ 387,000
Corporate tax rate		35.00%
Deferred tax assets		$ 165,136	$ 202,891	$ 191,314
Deferred tax liabilities		186,583	95,037	$ 79,654
Plan [Member]
Deferred Tax Assets and Liabilities [Abstract]
Corporate tax rate	21.00%
Net tax credits for Operating losses carryforwards [Member]
Deferred Tax Assets and Liabilities [Abstract]
Deferred tax assets		71,219	102,804
Temporary differences derivatives financial instruments [Member]
Deferred Tax Assets and Liabilities [Abstract]
Deferred tax assets		93,719	99,930
Temporary differences derivatives financial instruments [Member] \| Solar Plants in Spain [Member]
Deferred Tax Assets and Liabilities [Abstract]
Deferred tax assets		69,000
Temporary differences derivatives financial instruments [Member] \| ACT [Member]
Deferred Tax Assets and Liabilities [Abstract]
Deferred tax assets		18,000
Temporary differences tax/book amortization [Member]
Deferred Tax Assets and Liabilities [Abstract]
Deferred tax liabilities		113,432	28,810
Temporary differences tax/book value of contracted concessional assets [Member]
Deferred Tax Assets and Liabilities [Abstract]
Deferred tax liabilities		66,247	61,818
Other temporary differences [Member]
Deferred Tax Assets and Liabilities [Abstract]
Deferred tax assets		198	157
Deferred tax liabilities		6,904	$ 4,409
Temporary difference for accelerated tax amortization [Member] \| Solar Plants in Spain [Member]
Deferred Tax Assets and Liabilities [Abstract]
Deferred tax liabilities		51,000
Temporary difference for accelerated tax amortization [Member] \| Solana and Mojave [Member]
Deferred Tax Assets and Liabilities [Abstract]
Deferred tax liabilities		$ 63,000

Income Tax, Movements in deferred tax assets and liabilities (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016
Deferred Tax Assets [Abstract]
Beginning of period	$ 202,891	$ 191,314
Increase/decrease through the consolidated income statement	(31,421)	16,033
Increase/decrease through other consolidated comprehensive income (equity)	(13,312)	(5,701)
Other movements	6,978	1,245
End of period	165,136	202,891
Deferred Tax Liabilities [Abstract]
Beginning of period	95,037	79,654
Increase/decrease through the consolidated income statement	86,418	16,681
Increase/decrease through other consolidated comprehensive income (equity)	0	(62)
Other movements	5,128	(1,236)
End of period	$ 186,583	$ 95,037

Income Tax, Income tax benefit/(expense) (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Income Tax [Abstract]
Current tax	$ (1,998)	$ (1,018)	$ (2,182)
Deferred tax	(117,839)	(648)	(21,608)
Deferred tax expense (income) relating to origination and reversal of temporary differences	(98,508)	(648)	(22,492)
Deferred tax expense (income) relating to changes in tax rates	(19,331)	0	884
Total income tax benefit/(expense)	$ (119,837)	$ (1,666)	$ (23,790)

- Definition

The aggregate amount included in the determination of profit (loss) for the period in respect of current tax and deferred tax that relate to continuing operations. [Refer: Continuing operations [member]; Current tax expense (income); Deferred tax expense (income)]

+ References + Details

Income Tax, Effective income tax rate reconciliation (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Income Tax [Abstract]
Consolidated income / (loss) before taxes	$ 14,950	$ 3,333	$ (174,396)
Average statutory tax rate	30.00%	30.00%	30.00%
Corporate income tax at average statutory tax rate	$ (4,485)	$ (1,000)	$ 52,319
Income tax of associates, net	1,765	2,110	2,341
Differences in foreign tax rates	3,304	(4,930)	(2,389)
Permanent differences	19,324	11,121	(19,456)
Incentives, deductions, and tax losses carryforwards	(20,994)	(11,110)	(58,039)
Change in corporate income tax	(19,331)	0	884
U.S Internal Revenue Code Section 382	(96,328)	0	0
Other non-taxable income/(expense)	(3,092)	2,143	550
Total income tax benefit/(expense)	$ (119,837)	$ (1,666)	$ (23,790)
Limitation imposed on net interest expense, that exceeds EBITDA	30.00%
Limitation imposed on net interest expense, that exceeds EBIT	30.00%
Limitation imposed on NOL arising in tax years on taxable income	80.00%
NOL applicable carry forward period	20 years
BEAT applies on entity that exceeds taxable income percentage	10.00%

Third-party guarantees and commitments (Details) - USD ($)
$ in Thousands

3 Months Ended

12 Months Ended

Sep. 30, 2017

Dec. 31, 2017

Dec. 31, 2016

Third-party Guarantees [Abstract]

$ 32,428

$ 27,163

Issuance of guarantees previously issued by Abengoa

$ 112,000

643,083

668,201

^[1]

4,628,289

4,498,930

846,919

831,538

Accrued interest estimate during the useful life of loans

3,149,813

2,894,146

3,129,321

3,356,750

2018 [Member]

68,907

291,861

^[1]

215,117

183,929

31,174

27,225

Accrued interest estimate during the useful life of loans

141,867

136,032

340,481

332,408

2018/2019 and 2019/2020 [Member]

253,393

376,340

^[1]

457,853

388,679

53,620

49,422

Accrued interest estimate during the useful life of loans

230,014

263,398

630,108

617,852

2020/2021 and 2021/2022 [Member]

107,316

^[1]

539,466

459,361

54,395

48,740

Accrued interest estimate during the useful life of loans

259,845

246,904

559,856

543,927

Subsequent [Member]

213,467

^[1]

3,415,853

3,466,961

707,730

706,151