When burning solid fuels the efficiency of extracting useful energy and the pollution that is produced varies depending on the fuel used and the appliance in which the fuel is burned. There is particular concern regarding the health impacts of PM2.5 emissions. These are very small particles that can penetrate the lungs. Relative production from different methods of wood burning is illustrated below.
Burning wood on open fires is inefficient as well as polluting. The best option is a “DEFRA exempt Ecodesign Stove” or boiler. These are designs approved for use in smokeless areas but they are the best choice anywhere. The link leads to a list of the approved applicances. See also the case studies below for some examples.
It is also important to use dry wood as it is cleaner than any other solid fuel as well as producing more heat per unit mass or volume. Burning wet wood also increases the build up of tar inside chimneys, increasing the risk of chimney fires. In February 2020 the Goverment published a response to a consultation on Air quality: using cleaner fules for domestic burning. Section 13.1 gives information on the next steps:- what the government plans to do regarding sales of wood for use as a domestic fuel.
From February 2021 only dry wood (defined as having a moisture content of less than 20%) will be available for sale in quantities of less than 2 m3. Logs bought in small quantities, such as in nets from petrol stations, are assumed to be purchased for immediate consumption so they need to be dry. Small foresters will have an extra year to comply with the change.
It will still be possible to buy unseasoned logs in quantities of more than 2 m3. This is logical as it is assumed that householders buying larger quantities plan to dry their logs before use. Suppliers will have to supply seasoning instructions with all sales of wet wood. DEFRA has already published two very useful leaflets that are available via the links below.
For more information about wood fuel in Yorkshire follow the link to the Yorwoods website
Moor Sustainable Case studies using logs
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