If you have got read the history of charcoal making and its practical applications (PM70), you may be interested to know that you can make your own charcoal at home. To do this you need a fire pit or some other suitable fireplace and a Kadai Charcoal Maker.
I used a Bon-Fire Fire Pit which I slightly modified by cutting three 350mm lengths of 15mm copper pipe and threading these over the existing short legs to raise it about 300mm off the ground. This proved to be a good adaption as you can now sit round it to keep warm and it saves the grass.
The Charcoal Maker is a 450mm long steel drum, with doors at either end and two small chimneys on top. To make charcoal you fill it tightly with well seasoned lengths of hard wood about 30mm diameter. Close the ends and place the drum in a low fire of scrap wood. Next you build up the fire around the drum and watch the immediate effect on the wood in the drum as steam comes from the chimneys. Keep the fire going, though it doesn't need to be huge so don't waste too much wood on it. After about an hour flames will appear from the chimneys and around the doors. This is the wood gas burning off. After two hours, the flames will go out and the fire can be left to die down. Leave the drum overnight to cool as hot charcoal can spontaneously combust.
The next day, open an end and tip out your charcoal. I managed to make just over a kilo of high quality charcoal which, for a first try, I think was a success. The Kadai certainly works and I would be interested to try using it to make bio-char as well.