under paragraph (1) shall be not more than 50 percent of the total costs incurred in connection with the development, construction, acquisition of components for, or engineering of a demonstration project. (B) Maximum grant The maximum amount of a grant awarded under paragraph (1) shall be $5,000,000. (7) No ownership interest The United States shall hold no equity or other ownership interest in an energy storage system for which a grant is provided under paragraph (1). (8) Comparable wage rates Each laborer and mechanic employed by a contractor or subcontractor in performance of construction work financed, in whole or in part, by the grant shall be paid wages at rates not less than the rates prevailing on similar construction in the locality as determined by the Secretary of Labor in accordance with subchapter IV of chapter 31 of title 40, United States Code. (b) Rules and procedures