Definitions The following definitions apply throughout this chapter. Clean-burning fuels. The following are clean-burning fuels. Natural gas. Liquefied natural gas. Liquefied petroleum gas. Hydrogen. Electricity. Any other fuel that is at least 85% alcohol (any kind) or ether. Motor vehicle. A motor vehicle is any vehicle that has four or more wheels and is manufactured primarily for use on public streets, roads, and highways. It does not include a vehicle operated exclusively on a rail or rails. Nonqualifying property. This is property used in the following ways. Predominantly outside the United States. Predominantly to furnish lodging or in connection with the furnishing of lodging. By certain tax-exempt organizations. By governmental units or foreign persons or entities.