Fuels release their energies either through chemical means; such as, burning, or by nuclear means; such as, nuclear fission or nuclear fusion.
An important property of useful fuels is that their energies can be stored to be released only when needed, and that the releases are controlled in such a way that the energies can be harnessed to produce various kinds of work.
- Denatured ethanol, and other alcohols.
- Fuel mixtures containing 85 percent or more by volume of methanol, denatured ethanol, and other alcohols with gasoline or other fuels; such as, natural gas.
- Liquefied petroleum gas (propane).
- Coal-derived liquid fuels.
- Fuels (other than alcohol) derived from biological materials (biofuels; such as, soy diesel fuel).
- Electricity (including electricity from solar energy).