Starboard Value SC 13D ALGONQUIN POWER & UTILITIES / Starboard Value ownership change

Exhibit 99.1

JOINT FILING AGREEMENT

In accordance with Rule 13d-1(k)(1)(iii) under the Securities Exchange Act of 1934, as amended, the persons named below agree to the joint filing on behalf of each of them of a Statement on Schedule 13D (including additional amendments thereto) with respect to the shares of Common Shares, no par value, of Algonquin Power & Utilities Corp. This Joint Filing Agreement shall be filed as an Exhibit to such Statement.

Dated: June 30, 2023

Starboard Value and Opportunity Master Fund III LP By: Starboard Value A LP, its general partner   STARBOARD VALUE AND OPPORTUNITY S LLC By: Starboard Value LP, its manager   STARBOARD VALUE AND OPPORTUNITY C LP By: Starboard Value R LP, its general partner   Starboard X Master Fund II LP By: Starboard Value R LP, its general partner   STARBOARD VALUE A LP By: Starboard Value A GP LLC, its general partner   STARBOARD VALUE R LP By: Starboard Value R GP LLC, its general partner   STARBOARD VALUE AND OPPORTUNITY MASTER FUND L LP By: Starboard Value L LP, its general partner   STARBOARD VALUE L LP By: Starboard Value R GP LLC, its general partner   STARBOARD VALUE LP By: Starboard Value GP LLC, its general partner   STARBOARD VALUE GP LLC By: Starboard Principal Co LP, its member   STARBOARD PRINCIPAL CO LP By: Starboard Principal Co GP LLC, its general partner   STARBOARD PRINCIPAL CO GP LLC   STARBOARD VALUE A GP LLC   STARBOARD VALUE R GP LLC

By:	/s/ Jeffrey C. Smith
	Name:	Jeffrey C. Smith
	Title:	Authorized Signatory

/s/ Jeffrey C. Smith

JEFFREY C. SMITH

Individually and as attorney-in-fact for Peter A. Feld