The term Biomass most often refers to organic matter such as timber and crops grown specifically to be burnt to generate heat and power.
Biomass is sustainable and generally carbon neutral because the carbon released in the combustion process is offset by the carbon trapped in the organic matter by photosynthesis during its growth. To be truly carbon-neutral we need to make sustainable use of plants or trees as fuel, and replant them as we harvest them – so that the carbon is reabsorbed in a continuous and virtuous cycle.
Biomass Task Force
In October 2004 the Government asked the Biomass Task Force to suggest measures to optimise the contribution of biomass energy to renewables, sustainable farming, forestry and the rural economy. Their report can be downloaded from the DEFRA website at www.defra.gov.uk/farm/crops/industrial/energy/biomass-taskforce/index.htm .
The UK has the world’s largest and most efficient straw fired power station in Cambridgeshire. The 36MW plant generates over 270 GWh of electricity a year; enough power to heat and light 80,000 homes. The power station consumes around 200,000 tonnes/year of straw collected from farms within a 50 mile radius.
Domestic & Community Biomass
As not many of us have the room to grow biomass crops, the most popular use of biomass domestically is in wood burning stoves for water heating and space heating.
Emissions from wood used as fuel contain virtually no sulphur dioxide and very low levels of nitrous oxides, so won’t cause acid rain. If wood is seasoned for two years and burnt efficiently it gives off very low amounts of smoke particulates and the ash is an excellent fertiliser. Larger stoves are often fitted with a ‘Lamda’ sensor, which regulates the amount of oxygen added, and so optimises combustion efficiency.
The use of wood pellets, which are usually made of highly compressed waste sawdust, for heating is well established in countries such as North America, Sweden, Austria and Denmark. There is now an emerging pellet industry in the UK and there are currently two UK manufactures of wood pellet boilers based in Suffolk and Staffordshire.