Alternative fuel means any of the following:
(2) Denatured ethanol.
(3) Other alcohols.
(4) A mixture containing at least 85 percent (or an alternative percentage as specified by the Secretary of Transportation under 49 U.S.C. 32901(b)) of methanol, denatured ethanol, and other alcohols by volume with gasoline or other fuels.
(5) Natural gas.
(6) Liquefied petroleum gas.
(8) Coal derived liquid fuels.
(9) Fuels (except alcohol) derived from biological materials.
(10) Electricity (including electricity from solar energy).
(11) Any other fuel the Secretary of Transportation prescribes by regulation under 49 U.S.C. 32901(a)(1)(K).
40 CFR § 600.002
The following definitions apply throughout this part: