Exhibit 5.1
Jean Park
T+1 212 479 6131
jpark@cooley.com
December 3, 2025
Sunrun Inc.
600 California Street, Suite 1800
San Francisco, CA 94108
Re: Registration on Form S-8
Ladies and Gentlemen:
You have requested our opinion, as counsel to Sunrun Inc., a Delaware corporation (the “Company”), in connection with the filing by the Company of a Registration Statement on Form S-8 (the “Registration Statement”) with the Securities and Exchange Commission (the “Commission”) covering the offering of up to 38,854,154 shares (the “Shares”) of the Company’s Common Stock, par value $0.0001 per share, including (i) 34,690,741 shares of Common Stock pursuant to the Company’s Amended and Restated 2015 Equity Incentive Plan (the “2015 EIP”) and (ii) 4,163,413 shares of Common Stock pursuant to the Company’s 2015 Employee Stock Purchase Plan (the “ESPP and together with the 2015 EIP, the “Plans”).
In connection with this opinion, we have examined and relied upon (a) the Registration Statement and the related prospectuses, (b) the Company’s certificate of incorporation and bylaws, each as currently in effect, (c) the Plans and (d) the originals or copies certified to our satisfaction of such records, documents, certificates, memoranda and other instruments as in our judgment are necessary or appropriate to enable us to render the opinion expressed below. We have assumed the genuineness and authenticity of all documents submitted to us as originals, the conformity to originals of all documents submitted to us as copies, the accuracy, completeness and authenticity of certificates of public officials and the due authorization, execution and delivery of all documents by all persons other than the Company. As to certain factual matters, we have relied upon a certificate of an officer of the Company and have not independently verified such matters.
Our opinion is expressed only with respect to the General Corporation Law of the State of Delaware. We express no opinion to the extent that any other laws are applicable to the subject matter hereof and express no opinion and provide no assurance as to compliance with any federal or state securities law, rule or regulation.
On the basis of the foregoing, and in reliance thereon, we are of the opinion that the Shares, when sold and issued in accordance with the Plans, the Registration Statement and the related prospectuses, will be validly issued, fully paid and nonassessable (except as to shares issued pursuant to deferred payment arrangements, which will be fully paid and nonassessable when such deferred payments are made in full).
This opinion is limited to the matters expressly set forth in this letter, and no opinion has been or should be implied, or may be inferred, beyond the matters expressly stated. This opinion speaks only as to law and facts in effect or existing as of the date hereof and we have no obligation or responsibility to update or supplement this letter to reflect any facts or circumstances that may hereafter come to our attention or any changes in law that may hereafter occur.
Cooley LLP 55 Hudson Yards New York, NY 10001-2157
t: (212) 479-6000 f: (212) 479-6275 cooley.com