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BiomassModern wood burning stoves and boilers are making wood fuel an increasingly efficient and competitive alternative to fossil fuels. Use of woodfuel is widespread in some European countries such as Austria and Finland, and is becoming increasingly popular in Scotland. If it used to replace a heating oil boiler, a modern wood burning boiler can pay for itself in less than 6 years Biomass systems are usually designed for a particular fuel type, e.g. log, woodchip, straw, pellet or grain. Log
Modern automated log boilers are very robust and efficient, and can be an ideal solution where there is a cheap supply of logs. They are capable of burning any form of clean, dry wood, e.g. old palets, provided it is of suitable size. However they typically require manual loading once per day, then they will burn for 4-5 hours and fill a large and highly insulated accumulator tank to supply hot water and heating 24 hours per day.
Costs vary depending on the individual site and model. Some indicative costs for log boilers, including installation, flue, controllers, valves, and accumulator tanks are given below (excluding VAT):
Pellet
Wood pellets are made from compressed sawdust and are a relatively energy dense and free-flowing fuel. They produce very little ash, and there are a whole range of automated pellet stoves and boilers, from individual stoves suitable for rooms, through to boilers providing central heating and hot water for the entire house.
The typical costs for a automated pellet stove suitable for heating a room is around £3,500 ex VAT.
WoodchipWoodchip can be produced from any source of clean wood, such as forestry thinnings, recycled pallets, timber offcuts etc. Wood chip systems require less manual handling of fuel, and can be scaled up to much larger applications such as community heating schemes. Woodchips are loaded into a fuel store or hopper and are fed automatically to the boiler. By using a large hopper, the boiler requires less refilling. It is important to use woodchips of the right moisture content, size and consistency to prevent any problems with operation.
GrainGrain can be a good fuel, since poor quality grain has low selling value, but high energy content, and is easily handled. It produces more ash and clinker than wood pellets, but grain burning stoves have been developed successfully in Denmark. Where a cheap supply of grain is available, a grain burning stove may pay back in only a few years, when compared to the cost of replacing an oil-fired system. Recent rises in grain prices may make it unecomoical to burn grain, however most boilers which can handle grain can also handle wood pellets and wood chips. For more information see:
StrawBailed straw, and other fuels such as cardboard and waste wood can be burned in some boilers. Straw can provide a very economical and readily available fuel source. Some boilers will burn straw, as well as other clean fuels such as waste wood, grain, and cardboard. These are usually batch-burn boilers which require manual loading once per day, they then burn continuously to fill a large accumulator tank which provides continous hot water. For more information see Farm2000
Further InformationFor further information see: |
