Greener Charcoal Production

Start with a normal home-made charcoal maker (a sealed oil barrel with a fire underneath and a pipe leading from the top to the fire).

Then stick in a home-made jet turbine (basically a car turbocharger) to run off the gases and power a generator.

Then put a catalytic converter in the exhaust to clean them up. Use the cat and remaining exhaust temp to heat up the bottom of the barrel.