Phil Davis from Bowbridge is in the process of renovating his 16th century house, and is keen to make his as house carbon neutral as possible.
Wood fuel from a sustainable source is classified as carbon neutral. Although combustion of wood fuel releases CO2, this is offset by the CO2 absorbed by new trees.
The wood pellet boiler, installed in 2006, is part of a series of renewable measures Phil is incorporating into his home. When complete, he hopes to have a thermal storage tank to hold hot water delivered from his wood pellet boiler and from solar hot water panels on his garage roof. This will be linked to under-floor heating on all three floors of his home. Although his listed house cannot be double glazed, he has ensured that his roof is well insulated with 200mm of rockwool.
Wood pellets can be manufactured from short-rotation coppice such as willow, and about 30% of each tree goes to make pellets. Each tree will produce about three tonnes of pellets - enough to keep 200 homes warm for a week. Unfortunately there are currently no local wood pellet suppliers in the immediate Stroud area, but this is due to change in the near future as demand increases.
Phil bought his boiler from Wood Energy in Tiverton in Devon . He chose an Italian model from the Extraflame range, suitable for domestic use. It cost around £4,000 including installation. He can store about a tonne of wood pellets in his garage at any one time, and, using the boiler for an average of 5 hours a day, he needs to fill the hopper on the boiler every 3 to 4 days. The pellets are fed into the boiler automatically, and he is able to program his boiler to come on and off to his personal requirements.
Phil works in Devon and collects bags of wood pellets when he passes Wood Energy. This is obviously not an option for most people living in Stroud!
"The boiler is generally very easy to maintain, although it does need cleaning out every two weeks or so", says Phil. "It is straightforward to program, similar to a video machine from the 1980s!"
Richard Keating from Rodborough has also installed an Extraflame wood pellet boiler from Wood Energy at a cost of £4,000, although the flue pipe cost an additional £750! A back boiler directs heat into the wet central heating system and he has 10 radiators connected to his boiler. He finds the wood pellet boiler performs as well, if not better, than his former gas boiler.
Richard gets his pellets delivered, a tonne at a time, from Welsh Bio-Fuels. (This company is no longer trading). When a load is delivered to the Wilderness Centre in the Forest of Dean , he gets his pellets delivered by the same lorry. One tonne of wood pellets costs approximately £130, or £3 per 15kg bag. Delivery charges are extra. If the pellets are blown into the store, rather than being bagged, it reduces the cost. A pipe is needed to connect the lorry and the wood pellet store so they can be blown in.
Richard estimates that he needs to fill his boiler every 2 -3 days, depending on the temperature, at a cost of approximately £6. "After initial teething problems at the installation stage, our boiler works very well and is easy to maintain. Efficiency is as high as 90% and this is evident from the small amounts of ash produced, much less than a traditional open fire. We expect the boiler will need servicing about once a year," he says.
There are a number of certified biomass installers working in the Stroud District..
Welsh Biofuels no longer exist, but since this case study was created, new wood pellet suppliers have become available.
