The Government recently completed a Domestic Wood Use Survey, which underlines the need to burn wood in efficient wood burning stoves. The SIA (Stove Industry Alliance) commented that wood burning stoves are the most popular appliance for burning wood, followed by the much less efficient open fires.
In a world that focuses so much on high-tech advancements, when it comes to renewable energy people tend of think of solar, wind, hydro-electric and other high-tech methods. However, wood is a highly sustainable energy source. If managed from sustainable woodlands, burning wood on a high efficiency wood burning stove, can actually have a lower environmental CO2 impact than if the wood was left to naturally rot on the forest floor.
Sustainable Woodlands – A Growing Resource:
Trees are constantly growing, and unlike fossil fuels they are not a declining resource, a hardwood forest might accumulate up to 7 cubic metres (about 7 tonnes) of new wood per hectare each year, and softwood lots more. When seasoned this is approximately 5 tonnes of usable wood per hectare per year. Combine this with the fact that there are around 3 million hectares of woodland in the UK alone and you can see how abundant wood is.
Fossil Fuels vs Wood
Fossil fuels, which we have come to reply on as a heating source are not renewable and their supplies are becoming rapidly depleted. Fossil fuels are also extremely expensive to extract. Wood is very cheap in comparison. Wood takes CO2 out of the atmosphere as it grows, and returns it when it is burned. This is a closed carbon cycle with no overall increase in atmospheric CO2 levels.
How to Maximise The Efficiency of Wood
To ensure the lowest CO2 emissions possible, when burning wood, you should consider the following:
1. Select wood with a moisture content below 25%. Wood with a high moisture content is less efficient, and increases the risk of carbon monoxide poisoning. Wet wood will provide a less than adequate heat output, where you will need to burn much more for the same heat output of dry (seasoned) wood. A moisture meter will be able to tell you the moisture level of logs.
2. Avoid burning wood, which has contaminants such as paint or preservatives on. They can create toxic gases and can congest a flue.
3. When buying wood find out if it’s hard or softwood. Hardwood usually is the most efficient type of wood to burn and provides a good heat output for longer.
4. Avoid burning wood on an open fire, which will only have an efficiency of around 25%. A high efficiency wood burning stove by contrast, will have an efficiency of over 80%. This means over 80% of the heat produced goes on warming a room. The more efficient a stove is, the less you need to burn.