What is biomass?
Biomass is biological material derived from living, or recently living organisms. Biomass from many sources is used to generate heat and power or transport fuels in europe, these include, wood from woodlands, wood from the waste stream, woody energy crops like willow and miscanthus, cereal straw, poultry litter, cattle slurry, food waste, sugar beet, oil seed rape and wheat. To many, wood is perhaps the most familiar type of biomass used for fuel. It can be used in various forms from the familiar log to the wood chip and even as pellets and briquettes made from compressed saw dust.
Why use biomass?
Provided material is only harvested from sustainable sources such as managed woodland, biomass can help reduce green house gas emissions if it is used instead of gas and oil. For example, as trees grow they absorb carbon dioxide from the atmosphere. During photosynthesis the carbon is fixed into new tissue produced by the tree and oxygen is released. When the tree is burned the carbon in the tree is oxidised and returns to the atmosphere as carbon dioxide. This is a closed system that does not result in an increase of carbon dioxide in the atmosphere. Burning fossil fuels releases carbon that was removed from the atmosphere millions of years ago by animal and plant life. This leads to increased concentrations of carbon dioxide in the atmosphere.
Who produces biomass?
Biomass can be produced by businesses in many different sectors, mainly in agriculture, forestry or in waste recycling. Wood is often supplied to the energy market by an estate owner or by a contractor employed by an estate owner, it can be supplied by a tree surgeon or it may come from an existing wood processing business such as a saw mill. A list of woodfuel suppliers in England has recently been produced. There is huge potential to increase the amount of wood being suppied from small blocks of woodland in private ownership across Europe. Often this type of woodland has not been managed for many years. This can have negative impacts on biodiversity and can slow the rate at which trees in the forest grow. In England, one of the least wooded countries in Europe, it is estimated that in addition to the material harvested, 4 million tonnes of wood (FC woodfuel strategy) is produced by forests each year. This is a significant resource which, through sustainable management, could result in many rural jobs being created whilst providing a source of renewable energy and improving the condition of our woodlands. However, there are several important factors to consider before producing and selling biomass.
Who is using biomass?
Across Europe there are many hundreds of thousands of traditional open fires and log stoves used to provide heat to domestic buildings and this is perhaps the most familiar use of wood as a fuel. Open fires can be very inefficient and are not always the best way of using the resource. Closed stoves can be much more efficient (around 70%) open fires. Modern boilers using woodchip, pellets or logs can achieve efficenies of around 90%. These boilers can be used to supply heat to a single building or a single boiler can be used to supply heat to several buildings – this is known as district heating. These systems work well in larger buidlings such as schools, hospitals, council buildings or in new housing developments or blocks of flats. Many case studies exist on sytems that fall into this category. On the industrial scale wood is used to generate electricity. This is achieve by blending the wood with coal in conventional power stations, know as co-firing or by using wood as the principle fuel. At all of these scales some important issues should be considered when buying and using biomass fuels.