It has been about 20 years, but a guy in France was heating his house and running his car using a massive compost heap with plastic pipe coiled up in it (20 ft tall) and collecting the gas. By flowing water through the pipe he was able to heat his house nicely. In Mother Earth News some time in 1978 I think in the same issue as stacked wood housing. Internal temp of a compost pile can reach 158 F and kill action so the pipes serve two functions. Bio Gas and Compost goes hand in hand. The product is also a soil builder deluxe, study one and you understand the other.
Offered by Glen.