In order to produce electricity from biomass resources (short rotation forestry, wood wastes, sugar crops, starch crops, herbaceous lignocellulosic crops, oil crops, agricultural wastes, solid waste and refuse and industrial wastes) two rather different systems must be combined. These are a supply system that produces, collects and delivers the fuel and a power station that generates and distribute the electricity.
Biopower is the use of biomass to generate electrical power. There are four types of these systems: direct-fired, cofiring, gasification and small, modular. Most of the biopower plants use direct-fired systems, usually burning bioenergy feedstocks directly to produce steam. Many coal-fired plants use cofiring systems. Gasification systems use high temperatures and an oxygen-starved environment to convert biomass into gas. Gas (methane) is also produced in landfills in the decay of biomass. A small, modular system generates electricity at a capacity of 5 MW or less, specially in small towns by using either each one of the above systems.
Heat can be used to chemically convert biomass into a fuel oil. This process is called pyrolysis and it occurs when biomass is heated in the absence of oxygen. After pyrolysis, biomass turns into a liquid, pyrolysis oil, which can be burned like petroleum to generate electricity.