Bioenergy comprises all energy produced from biomass (which represents more than 80% of the energy production in this sector) or from biofuels. Regarding Portugal, the biofuel highlighted is biogas, a mixture of gases produced by the biological decomposition of organic matter, in the absence of oxygen.

Biomass is all the organic matter of plant or animal origin capable of regenerating in a short period of time and in a sustainable way. Biomass comprises forest by-products, agriculture, livestock, and organic municipal waste.