Exhibit 32.1

CHIEF EXECUTIVE OFFICER CERTIFICATION PURSUANT TO 18 U.S.C. SECTION 1350, AS ADOPTED PURSUANT TO SECTION 906 OF THE SARBANES-OXLEY ACT OF 2002

Pursuant to 18 U.S.C. §1350, the undersigned officer of Sunnova Energy International Inc. (the “Registrant”) hereby certifies that, to his knowledge, the Registrant’s Annual Report on Form 10-K for the year ended December 31, 2020 (the “Annual Report”) fully complies with the requirements of Section 13(a) or 15(d), as applicable, of the Securities Exchange Act of 1934 and that the information contained in the Annual Report fairly presents, in all material respects, the financial condition and results of operations of the Registrant.

Date:	February 25, 2021	/s/ William J. Berger
		William J. Berger
		Chief Executive Officer