In this chapter:
(2) The term “energy-efficient maintenance” includes—
(3) The term “hybrid”, with respect to a motor vehicle, means a motor vehicle that draws propulsion energy from onboard sources of stored energy that are both—
(4)
The term “operational energy” means the energy required for training, moving, and sustaining military forces and weapons platforms for military operations. The term includes energy used by tactical power systems and generators and weapons platforms.
(5)
The term “petroleum” means natural or synthetic crude, blends of natural or synthetic crude, and products refined or derived from natural or synthetic crude or from such blends.
(6) The term “renewable energy source” means energy generated from renewable sources, including the following:
(Added Pub. L. 112–81, div. B, title XXVIII, § 2821(a)(1), Dec. 31, 2011, 125 Stat. 1689; amended Pub. L. 115–91, div. B, title XXVIII, § 2831(c)(6), Dec. 12, 2017, 131 Stat. 1858.)