40 U.S.C. § 591: Purchase of electricity

(a) General Limitation on Use of Amounts.—A department, agency, or instrumentality of the Federal Government may not use amounts appropriated or made available by any law to purchase electricity in a manner inconsistent with state law governing the provision of electric utility service, including—(1) state utility commission rulings; and (2) electric utility franchises or service territories established under state statute, state regulation, or state-approved territorial agreements. (b) Exceptions.—(1) Energy savings.—This section does not preclude the head of a federal agency from entering into a contract under section 801 of the National Energy Conservation Policy Act (42 U.S.C. 8287). (2) Energy savings for military installations.—This section does not preclude the Secretary of a military department from—(A) entering into a contract under section 2394 of title 10; or (B) purchasing electricity from any provider if the Secretary finds that the utility having the applicable state-approved franchise (or other service authorization) is unwilling or unable to meet unusual standards of service reliability that are necessary for purposes of national defense.