Exhibit 99.1

JOINT FILING AGREEMENT

PURSUANT TO RULE 13d-1(k)

The undersigned acknowledge and agree that the foregoing statement on Schedule 13G is filed on behalf of each of the undersigned and that all subsequent amendments to this statement on Schedule 13G may be filed on behalf of each of the undersigned without the necessity of filing additional joint filing agreements. The undersigned acknowledge that each shall be responsible for the timely filing of such amendments, and for the completeness and accuracy of the information concerning him or it contained herein or therein, but shall not be responsible for the completeness and accuracy of the information concerning the others, except to the extent that he or it knows or has reason to believe that such information is inaccurate.

	Lightning Power Holdings, LLC

	Signature:	/s/ Jeffrey Wade
	Name/Title:	Jeffrey Wade/Chief Compliance Officer
	Date:	February 6, 2026

	Fund III Lightning Holdings, LLC

	Signature:	/s/ Jeffrey Wade
	Name/Title:	Jeffrey Wade/Chief Compliance Officer
	Date:	February 6, 2026

	Granite Energy, LLC

	Signature:	/s/ Jeffrey Wade
	Name/Title:	Jeffrey Wade/Chief Compliance Officer
	Date:	February 6, 2026

	Granite Energy Holdings, LLC

	Signature:	/s/ Jeffrey Wade
	Name/Title:	Jeffrey Wade/Chief Compliance Officer
	Date:	February 6, 2026

	LS Power Equity Partners III, L.P

	Signature:	/s/ Jeffrey Wade
	Name/Title:	Jeffrey Wade/Chief Compliance Officer
	Date:	February 6, 2026

	Signature:	/s/ LS Power Partners III, L.P.
	Name/Title:	LS Partners III L.P./its general partner
	Date:	February 6, 2026

	Signature:	/s/ LS Power Fund III G.P., LLC
	Name/Title:	LS Power Fund III G.P., LLC/its general partner
	Date:	February 6, 2026

	LS Power Partners III, L.P.

	Signature:	/s/ Jeffrey Wade
	Name/Title:	Jeffrey Wade/Chief Compliance Officer
	Date:	February 6, 2026

	Signature:	/s/ LS Power Fund III G.P., LLC
	Name/Title:	LS Power Fund III G.P., LLC/its general partner
	Date:	February 6, 2026

	LS Power Fund III G.P., LLC

	Signature:	/s/ Jeffrey Wade
	Name/Title:	Jeffrey Wade/Chief Compliance Officer
	Date:	February 6, 2026

	LS Power Equity Advisors, LLC

	Signature:	/s/ Jeffrey Wade
	Name/Title:	Jeffrey Wade/Chief Compliance Officer
	Date:	February 6, 2026

	David Nanus

	Signature:	/s/ David Nanus
	Name/Title:	David Nanus
	Date:	February 6, 2026

NRG ENERGY, INC. SCHEDULE 13G