(a) Subject to subsection (b), the Secretary of a military department may enter into contracts for periods of up to 30 years—

(1) under section 2917 of this title; and

(2) for the provision and operation of energy production facilities on real property under the Secretary’s jurisdiction or on private property and the purchase of energy produced from such facilities.

(b) A contract may be made under subsection (a) only after the approval of the proposed contract by the Secretary of Defense.

(c) The costs of contracts under this section for any year may be paid from annual appropriations for that year.

(d) The Secretary concerned shall ensure energy security and energy resilience are included as critical factors in the provision and operation of energy production facilities under this section.