Energy from biomass

What is biomass?
Biomass is material from living things. This could be plant material, animal material or even bacteria. Organic matter can be burned to provide heat, or fermented to produce gas.
How is biomass energy collected?
Plant material such as wood or hay can be burned to provide heat to raise steam and so generate electricity in a power station.

Animal waste (e.g. animal slurry from a farm) can be treated to provide gases that can be burned to generate electricity. Landfill sites emit gases (mainly methane) that can also be used to provide energy. Some plant materials such as sugar cane and maize (sweetcorn) can be fermented to produce alcohol. Alcohol can be used in cars as a substitute for petrol.

Crops can be grown as energy crops rather than food crops. Oilseed rape (the fields of yellow flowers you see in the UK in summer) produces oil. About 32 per cent of the seed is oil. After treatment with chemicals it can be used as a fuel in diesel engines, called RME (rape methyl ester).
Where is biomass energy used?
About 200 years ago biomass in the form of wood was the major source of energy. In many parts of the developing world biomass (not always from trees) is still the major source of energy.

In Brazil, large numbers of cars run on alcohol rather than petrol. In the Western world, people are developing ways of using biomass as an alternative to fossil fuels. There is a large biomass plant in Sweden, while in the UK attempts are being made to develop a power station that will run solely on wood from a nearby farm. Advantages
Biomass is a renewable resource – for example, trees can be replanted or coppiced. Energy can be extracted from wastes. Biomass energy can be used in similar ways to fossil fuels. Sources of biomass are readily available worldwide.
Disadvantages
Biomass energy sources are no more environmentally friendly than fossil fuels because they recycle carbon into the atmosphere when they are burned. Carbon dioxide, which is produced when these fuels are burned, is a major cause of the greenhouse effect.
The following is an extract from a paper by the UK government's Department of the Environment, Transport and the Regions, entitled Energy in Brief, published in December 1999. The full publication can be obtained at: www.environment.detr.gov.uk/des20/chapter0/2.htm#chapter2