EX-8.1


		First Reserve Sustainable Growth Corp. [ ], 2022 Page 2

(iii)

any representations and statements made in any of the Documents or the Officer’s Certificate qualified by knowledge, belief, or materiality (or comparable qualification) are true, complete, and correct in all respects and will continue to be true, complete, and correct in all respects at all times up to and including the completion of the Business Combination, in each case without such qualification;

(iv)

the Documents represent the entire understanding of the parties with respect to the Business Combination, there are no other written or oral agreements regarding the Business Combination other than the Business Combination Agreement and the other agreements referred to therein, and none of the material terms and conditions thereof have been or will be waived or modified;

(v)

all documents, records, and papers submitted to us as originals (including signatures thereto) are authentic; all documents, records, and papers submitted to us as copies conform to the originals; all relevant documents, records, and papers have been or will be, as applicable, duly executed in the form presented to us; and all parties to such documents, records, and papers had or will have, as applicable, the requisite corporate powers and authority to enter into such documents, records, and papers and to undertake and consummate the Business Combination; and

(vi)

all applicable reporting requirements have been or will be satisfied.

If any of the assumptions described above are untrue for any reason, our opinion may be adversely affected.

Our opinion is based on current provisions of the Internal Revenue Code of 1986, as amended (the “Code”), the legislative history to the Code, the Treasury Regulations promulgated thereunder, published pronouncements of the Internal Revenue Service, case law, and such other authorities as we have considered relevant, all as in effect as of the date hereof. The authorities upon which our opinion is based are subject to change or differing interpretations, possibly with retroactive effect. Any change in applicable laws or facts and circumstances surrounding the Business Combination, or any inaccuracy in the statements, facts, assumptions, and representations on which we have relied, may affect the continuing validity of our opinion. We assume no responsibility to inform you of any such change or inaccuracy that may occur or come to our attention (or to supplement or revise our opinion to address any such change or inaccuracy) subsequent to the date hereof. No opinion is expressed as to any transactions occurring in connection with the Business Combination, other than insofar as such transactions bear on the U.S. federal income tax consequences of the Merger (as defined in the Registration Statement), or as to any matter other than those specifically covered by this opinion. In particular, our opinion is limited to the matters discussed in the Merger Tax Disclosure and does not include any tax consequences not expressly addressed therein. Further, statements contained therein that FRSG or EO Charging “believes,” “expects,” “intends,” or other similar phrases are not legal conclusions and do not constitute our opinion.

Based upon and subject to the foregoing, we confirm that the statements set forth in the Registration Statement under the heading “Material U.S. Federal Income Tax Considerations—Material U.S. Federal Income Tax Considerations with Respect to the Merger for Holders of FRSG Class A Common Stock and FRSG Warrants—Tax Characterization of the Merger,” insofar as they address the material U.S. federal income tax considerations of the Merger for beneficial owners of FRSG Class A Common Stock and FRSG Warrants (each as defined in the Registration Statement) and discuss matters of U.S. federal income tax law and regulations or legal conclusions with respect thereto, and except to the extent stated otherwise therein, are our opinion, subject to the assumptions, qualifications, and limitations stated herein and therein.

This opinion is rendered solely in connection with the filing of the Registration Statement and is not to be relied upon for any other purpose. We hereby consent to the filing of this letter as an exhibit to the Registration Statement and to the references therein to us. In giving such consent, we do not thereby admit that we are within the category of persons whose consent is required under Section 7 of the Securities Act of 1933, as amended.

Very truly yours,

Vinson & Elkins LLP