The term biomass alludes to solar energy, converted into organic matter by vegetation, which can be recovered by direct combustion or by transforming this matter into other fuels, like alcohol, methanol or oil. It is also possible to obtain biogas, which has a similar composition to natural gas, from organic waste.

Advantages: it is a clean energy source and leaves few waste products, which are also biodegradable. It is also produced continually as a consequence of human activity.

Disadvantages: it is necessary to have large quantities of plants and therefore of land. Attemps are being made to "manufacture" suitable vegetable matter using genetic engineering. Its efficiency is lower than that of fossil fuels and it produces gases, like carbon dioxide, which increase the greenhouse effect.