While much of the UK is today paralysed by heavy snowfall, I along with many others, have decided not to risk the journey to work and am sitting here writing this post at the dining room table looking out over a garden draped in winter wonderland finery. While driving home last night I listened to news reports assuring the population that there is enough gas available to satisfy UK domestic demand to see us through the cold spell despite concerns over low storage capacity. As I sit here I recall conversations with a colleague about his wife's foraging trips for fuel for their wood burning stove and wonder how easy it is to become less reliant on main-supplied energy.
Although many more people are coming back home to a log fire, whether in an open grate or in a domestic log burning stove, what is the potential for fulfilling your full domestic heating and hot water needs with fuelwood? Is it practical for the average householder and what information is out there on other renewable options?
The UK Government is committed to at least an 80% reduction in greenhouse gas emissions by 2050 which will undoubtedly mean reducing domestic emissions to near zero by this date according to the UK Department of Energy & Climate Change (DECC). Much of the effort directed to achieving this is currently being coordinated by the Energy Saving Trust but one of the most comprehensive websites for information on this topic is the Renewable Energy Centre which details information on home energy saving, solar heating and energy (via photovoltaics), ground and air source heating, wind energy, hydroelectric power, biomass, and wave and tidal power.
As I am particularly interested in fuelwood fired heating I did a bit of digging around on the web to see what information is available to the average householder. Open wood fires might look nice and appear to put out a fair bit of heat into a room but tend to use a lot of logs and generate a good deal of smoke and ash. Not surprisingly, I was interested to learn that their efficiency is low (~25%) compared to a log stove (~70%). Some of the more sophisticated log stoves have lambda sensors which control the amount of oxygen for a more efficient burn with improved efficiencies. In addition to heating a room stoves with back boilers are available which can heat a few radiators. For full domestic heating, log boilers are recommended and these can be manually batch loaded daily with well seasoned logs. These have much higher efficiencies, typically up to 90%. The Biomass Energy Centre has an information sheet comparing the relative merits of logs and pellets for use in stoves and boilers. Storage space may be an significant issue with an average domestic house requiring 5 tonnes of logs (at around £300/t) annually taking up 10 to 14 cubic metres of spaces, though one assumes that one could get away with smaller quantities delivered more often. The Forestry Commission's research agency Forest Research is looking into our national fuelwood resources and, along with a strategy of increasing the area (~12%) of the UK covered in woods and forests, is trying to encourage the use of fuelwood. One hopes that fuelwoods costs may come down as supply increases in the future. Currently there are savings (£170-400 pa) to be had using wood compared to solid fuel or electricity but not if you are currently using gas to heat your home. For log burning, the installation costs range from £3000 (stoves) to £9000 (boilers) but there are huge savings in CO2 emissions, around 9.6 tonnes pa if replacing a coal fired boiler with a wood fired boiler.
Grant aid for householders for installation of renewable energy, including fuelwood heating systems, is being made available by the DECC under the Low Carbon Buildings Programme. Until the end of 2010 a maximum of £1,500 or 30% of eligible costs, whichever is the lower, can be applied for. One would hope that more extensive funding incentives will become available for householders over the coming years, even in the form of interest free loans. Even if fuelwood heating is an appropriate solution, which is unlikely for many homeowners for a variety of reasons, the high initial outlay cost will put many people off.
For those interested in the scientific aspects of fuelwood, CAB Direct has over 7000 bibliographic records of the latest published research.
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