Bioenergy is the energy which is stored in biological matter or “biomass”. This can be anything from plants to straw to slurry to food waste and even sewage.
When these materials are used for their energy content, they are referred to as “feedstocks”. Sometimes feedstocks are grown specifically for their bioenergy content (known as “energy crops”), while others are waste products from industries such as agriculture, food processing or timber production.
This depends on the type of biomass being used. Dry, combustible feedstocks are burnt in boilers or furnaces, while wet feedstocks are put into sealed tanks, where they create biomethane gas as they rot.
This gas is captured throughout the rotting process and is then burnt.
Burning the biomass or biomethane produces heat which can be used to warm homes, shops, and offices, or it can be used to drive steam turbines to generate electricity much in the same way as coal or gas-fired power plants.
Bioenergy is a very flexible source of energy (it can be stored, and then turned up and down quickly to meet demand) which makes it a great backup for other renewable technologies, like wind turbines and solar panels, which depend on the weather to generate electricity.