Burning wood in a fireplace is the oldest and most traditional method of using biomass for energy purposes. Biomass or biorenewable sources are organic materials of recent biological origin – therefore quickly convertible – that can be used as an energy source. Today, biomass of agricultural, forestry and livestock origin is used along with waste to extract energy. Direct combustion is the most practiced method to generate steam and drive the turbines. But there are other more sophisticated methods to create biogas (anaerobic digestion), bioethanol (alcohol fermentation) and biodiesel (oilseed pressing).