Woodland biomass is a renewable resource that can be used to generate energy. Two significant factors affect the calorific value or amount of available heat per unit (volume) of fuel; moisture content and wood density
Moisture content has the greatest effect on calorific value. Any water in timber has to boil away before the wood will burn, this will reduce the net energy released as useful heat (as opposed to steam). Well-seasoned logs can have approximately twice the calorific value of green logs.
The type of tree a log comes from can have some impact on the calorific value, however it is usually minimal. Most of the variation in calorific value between species comes from natural differences between moisture content in fresh cut logs (Ash has a particularly low moisture content when green).
Hardwoods (deciduous, broadleaved tree species) tend to be denser than softwoods (evergreen, coniferous species).
A tonne of hardwood logs will therefore occupy a smaller space than a tonne of softwood logs.
Denser wood tends to burn for longer periods meaning that fewer ‘top-ups’ are required to keep a stove or boiler burning for a given length of time.
For some useful tips on drying logs please click here
Funding and grants
The Wood fuel Woodland Improvement Grant (WIG) supports sustainable production of wood fuel and other timber products and offers 60% towards costs supporting:
- forest roads, access tracks and other harvesting related infrastructure;
- woodland inventory and costs associated with managing harvesting contracts.
For information on eligibility and how to apply, and further information on other funding sources, please click here
Source: Wood as fuel (Forestry Commission)