INDEPENDENT REGISTERED PUBLIC ACCOUNTING FIRM’S CONSENT
We consent to the incorporation by reference in this Registration Statement of Fortistar Sustainable Solutions Corp. (the “Company”) on Form S-1 pursuant
to Rule 462 (b) under the Securities Act of 1933, as amended, of our report dated January 15, 2021, which includes an explanatory paragraph as to the Company’s ability to continue as a going concern, with respect to our audit of the financial
statements of Fortistar Sustainable Solutions Corp. as of December 31, 2020 and for the period from August 25, 2020 (inception) through December 31, 2020, which
report appears in the Prospectus on Amendment No. 2 to Form S-1, which is part of the Registration Statement of Fortistar Sustainable Solutions Corp. (File No. 333-251922).
/s/ Marcum llp
New York, NY
January 26, 2021