Alternative fuels, known as non-conventional and 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 bio-diesel bio-alcohol (methanol ethanol butane) refuse-derived fuel chemically stored electricity (batteries and fuel cells), hydrogen non-fossil methane non-fossil natural gas vegetable oil propane, and other biomass sources.