(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.