POWER OF ATTORNEY FOR SECTION 16 REPORTING OBLIGATIONS

This filing is a limited power of attorney granted by Brian C. Cox, a Director of Ameresco, Inc., to John W. Pickett, Nina Andersson-Willard, and Lenka Patten. This power of attorney authorizes the appointed individuals to execute and file all necessary Section 16 reports (Forms 3, 4, and 5) with the SEC on behalf of Mr. Cox. It also grants them the authority to gather information regarding the company's securities and take any other actions deemed beneficial or legally required. The power of attorney remains in effect until Mr. Cox is no longer required to file such reports or until it is revoked. The filing also clarifies that neither the company nor the appointed attorneys-in-fact assume liability for Mr. Cox's compliance with Section 16 of the Exchange Act.