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Woodfuel

Coppiced logs

Coppiced stumps

Logs for firewood

Wood is a form of biomass, which is created by the process known as photosynthesis – the chemical reaction combining water and carbon dioxide using energy from the Sun. It is the reverse reaction that we call ‘combustion’ – the process of breaking down the biomass and releasing heat energy, which can be used for heating, cooking, drying etc. The fact that wood has roots and leaves makes it a tree!

Trying to heat a house from wood is difficult due to the ineffective stoves and poor quality fuel that we use in the UK. Poorly designed houses don’t help, but all this can be changed, and as we all face-up to the reality of climate change, said to present the UK with colder winters, then the work here is more than relevant.

Firewood/woodfuel suppliers in the United Kingdom take great pride in promoting the fact that their firewood is either air-dried, barn-dried or kiln-dried to between 20% - 35% moisture content, which indicates that there is an understanding that wood needs to be dried before it is burned!

Some firewood suppliers ‘accurately’ guess the wet-weight moisture content of their wood, some don’t know and will just tell you that they have had it ‘under cover for a year.’ A few actually use a meter to determine the moisture content of their firewood, however sticking a 3mm probe into the end of the log will never give you an accurate account of the moisture content in the middle of a 250cm long log (beware that old plum), which may be 20% higher.

There are firewood suppliers who do actually test moisture at the middle/heart of the log, and such endeavour deserves high praise, even if they are still selling you too much water in your wood!

If, for example, as a nation, we burn 500,000 tonnes of firewood a year, dried to 20% moisture content, then we have paid for and wasted 100,000 tonnes of water! If wood is £100 per tonne then £10million has been wasted on driving water from wood!

Burning wood at between 5-10% moisture content (which is a figure that most firewood suppliers would consider to be ‘theoretical’, and every other stove manufacturer an impossibility) provides 5000kWh of energy per tonne. Burning wood at 20% moisture content provides 4000KwH of energy per tonne. For every tonne of firewood we burn at 20% moisture content instead of 5% moisture content, we are wasting 1000KwH of energy:


100,000 TONNES OF WATER =
100 MILLION kWh of energy wasted annually!


Efficient combustion requires technologically advanced woodstoves designed specifically
to burn coppice / small poles, dried to a uniform and consistent standard.
This is the mantra for Black Mountain Woodfuels.

'Stick Farming' - Click here to download a PDF of our feature article in Living Woods 17 (July/Aug 2011)
 'New Directions' - Click here to download a PDF of our feature article in Living Woods 18 (Sept/Oct 2011)
PAR-CHAR and The Coppice Stove are registered UK trademarks (2565580 & 2569855) owned by Black Mountain Woodfuels.
All prices include VAT& Delivery.
© BMWF 2011

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