10 U.S.C. § 2922j

(a) In General .— Not less frequently than annually, the Secretary of Defense shall submit to Congress a report that, for the year covered by the report— (1) identifies each instance in which the Secretary purchased drop-in fuel that was not cost-competitive with traditional fuel; and (2) for each instance identified under paragraph (1), states whether the purchase was based on a military requirement or not. (b) Definitions .— In this section: (1) The term “drop-in fuel” means a neat or blended liquid hydrocarbon fuel designed as a direct replacement for a traditional fuel with comparable performance characteristics and compatible with existing infrastructure and equipment. (2) The term “traditional fuel” means a liquid hydrocarbon fuel derived or refined from petroleum.