EX-5.1

Exhibit 5.1

Davis Polk & Wardwell LLP

450 Lexington Avenue
New York, NY 10017

davispolk.com

June 24, 2021

The AES Corporation

4300 Wilson Boulevard

Arlington, VA 22203

Ladies and Gentlemen:

We have acted as special counsel to the AES Corporation, a Delaware corporation (the “Company”) in connection with the Company’s offers (the “Exchange Offers”) to exchange its 1.375% Senior Notes due 2026 (the “New 2026 Notes”), issued pursuant to an indenture dated as of December 8, 1998 (the “Base Indenture”) between the Company and Deutsche Bank Trust Company Americas, as successor trustee (the “Trustee”), as amended by the twenty-sixth supplemental indenture dated as of December 4, 2020 (the “Twenty-Sixth Supplemental Indenture” and together with the Base Indenture, the “Indenture”), for any and all of its outstanding 1.375% Senior Notes due 2026 (the “Old 2026 Notes”), and its 2.450% Senior Notes due 2031 (the “New 2031 Notes” and, together with the New 2026 Notes, the “New Notes”) issued pursuant to the Indenture for any and all of its outstanding 2.450% Senior Notes due 2031 (the “Old 2031 Notes” and, together with the Old 2026 Notes, the “Old Notes”) pursuant to the registration statement on Form S-4 (the “Registration Statement”) filed by the Company with the Securities and Exchange Commission.

We, as your counsel, have examined originals or copies of such documents, corporate records, certificates of public officials and other instruments as we have deemed necessary or advisable for the purpose of rendering this opinion.

In rendering the opinion expressed herein, we have, without independent inquiry or investigation, assumed that (i) all documents submitted to us as originals are authentic and complete, (ii) all documents submitted to us as copies conform to authentic, complete originals, (iii) all signatures on all documents that we reviewed are genuine, (iv) all natural persons executing documents had and have the legal capacity to do so, (v) all statements in certificates of public officials and officers of the Company that we reviewed were and are accurate and (vi) all representations made by the Company as to matters of fact in the documents that we reviewed were and are accurate.

Based upon the foregoing, and subject to the additional assumptions and qualifications set forth below, we are of the opinion that the New Notes, when the New Notes are executed, authenticated and delivered in exchange for the Old Notes in accordance with the terms of the Indenture and the Exchange Offers, will constitute valid and binding obligations of the Company enforceable in accordance with their terms, subject to applicable bankruptcy, insolvency and similar laws affecting creditors’ rights generally, concepts of reasonableness and equitable principles of general applicability; provided that we express no opinion as to the (x) enforceability of any waiver of rights under any usury or stay law, (y) effect of fraudulent conveyance, fraudulent transfer or similar provision of applicable law on the conclusions expressed above or (z) validity, legally binding effect or enforceability of any provision that permits holders to collect any portion of stated principal amount upon acceleration of the New Notes to the extent determined to constitute unearned interest.