alternative fuels

Synonyms

non-conventional fuels, advanced fuels, non-polluting fuel

Definition

Materials or substances other than conventional fossil fuels or nuclear materials which may be burned in order to generate energy.

Wikipedia definition:

Alternative fuels, known as non-conventional or advanced fuels, are any materials or substances that can be used as fuels, other than conventional fuels like; fossil fuels (petroleum (oil), coal, and natural gas), as well as nuclear materials such as uranium and thorium, as well as artificial radioisotope fuels that are made in nuclear reactors. Some well-known alternative fuels include biodiesel, bioalcohol (methanol, ethanol, butanol), chemically stored electricity (batteries and fuel cells), hydrogen, non-fossil methane, non-fossil natural gas, vegetable oil, propane and other biomass sources.

Source: Wikipedia - Alternative fuel