According to the European Union’s Renewable Energy Directive, biomass is the biodegradable part of products, waste, and residues from agriculture, forestry and related industries (including fisheries and aquaculture). Unlike coal, oil, and natural gas, biomass is a renewable resource and the bioenergy produced from it has a good carbon balance: when biomass or biogas is burned, only about as much carbon dioxide is released as was removed from the atmosphere during the plant growth. Bioenergy is extracted from the raw material biomass, i.e. plants, biowaste, wood, or liquid manure and can be divided into solid, liquid and gaseous biomass. The first includes wood and straw, which are used to produce electricity and heat through combustion. Liquid biomass in the form of vegetable oils can be used as fuel for vehicles and in CHP plants. The latter, also called biogas, is produced by the fermentation of biowaste and plant/animal residues. It can hereby be burned in CHP plants, or refined and fed into the natural gas grid.