Why Wood Burning may be Sustainable
Trees consume carbon dioxide from the atmosphere when they grow. They release it back to the atmosphere if they die and decompose. Burning wood provides heat and carbon dioxide emissions – but the wood would emit CO2 eventually anyway when it decomposed.
This means that some people consider wood burning to be a sustainable form of energy whilst others do not. The author’s view is that energy from wood is more sustainable than energy from gas, oil or coal but is less sustainable that energy from wind and solar.
Figure 1: Wood burning stove. [1]
A Natural Energy Store
One of the great benefits of wood is that it stores energy. It grows in summer when it is warm and energy from natural sources tends to be abundant and it is normally burnt in winter which is when we tend to burn more gas, oil and coal to keep the lights on.
Air Quality Issues
Burning wood can also cause significant PM2.5 particulate emissions that are harmful to human health. Burning seasoned wood in a modern stove considerably reduces these emissions. The UK government is currently introducing a ban on the sale of unseasoned logs to help improve air quality nationally.
Seasoned Logs
Seasoned logs have a moisture content of less than 20%. As well as reducing particulate emissions they give off more heat when burned and they are easier to light. You can check whether your logs have been seasoned properly with a moisture metre.
The Right Time to Burn
In homes where the alternative forms of heating are electric it can be beneficial to monitor the current carbon emissions due to electricity generation. If its very windy and sunny it could be better to save lighting the fire for another day. There is an App called Grid Carbon Intensity calculator that will tell you how green electricity currently is based on the different types of generation being used. At the time of writing (sunny afternoon with some wind) emissions are 236 grams of carbon per kilowatt hour.
Clean Burning Guidelines
Guidelines for enjoying burning wood in an environmentally responsible way.
- Only burn seasoned wood
- Use a stove or log burner – its much more efficient than an open fire
- Only burn wood when you need the heat
- Source your wood locally
- If you have an efficient electric heating system try and burn your logs when grid carbon intensity is high (e.g. over 250 grams CO2 per kilowatt hour)
- Use lots of kindling and allow the fire lots of air to reduce particulate emissions
- Make sure the burner is well maintained and the chimney is regularly swept
About Pager Power
Pager Power undertakes technical assessments for developers of renewable energy projects and tall buildings. For more information about what we do, please get in touch.
[1] Rooban N (August 2020) from unsplash.com. Last accessed on April 2021. Available at: https://unsplash.com/photos/kQMREmg7JUg
