Funnily enough, just the other day I was thinking of a wood gas generator. It would be interesting to see an efficiency comparison, as the wood gas generator al

Funnily enough, just the other day I was thinking of a wood gas generator. It would be interesting to see an efficiency comparison, as the wood gas generator also gives out a lot of waste heat. The internal combustion engine is itself not more than 25% efficient so you won't get great efficiency there either, if you add up the losses from generating the wood gas. But it should still be much better than these thermoelectric generators.