As you may have seen, Gervais Sawyer has contributed an interesting article on charcoal: http://www.swog.org.uk/articles/small-woodland-owners-and-charcoal-by-gervais-sawyer/
I actually agree with much of what he says, in particular that:
- energy-wise, charcoal makes no sense at all. it's much better to just use the wood, rather than waste all that heat converting it to charcoal.
- pollution wise, a traditional charcoal kiln emits a lot of smoke!
However, that's not the end of the story. Other points to consider are:
- if people are using charcoal anyway, is it not better that it comes from a local source?
- the wood being converted to charcoal may not have any other use, especially if the extraction route is difficult, as charcoal is a lot lighter to carry out by hand than wood.
- if making charcoal and selling it provides money to pay for management of the wood, that could be a positive thing for biodiversity.
I wonder if what's needed is a cheap and simple design for a retort kiln, that lets you burn scrappy wood to convert the better wood to charcoal, and the gases driven off in the process are used to provide part of the heat, thereby reducing the pollution?
Anyone aware of such a design? We improvised something with a couple of metal drums (a design suggested by Gervais) but it only works on a very small scale. http://peplers.blogspot.com/2008/06/charcoal-kiln-test-and-stuff-thats.html
Mike
