OK Walt, technically all this carbon was probably biologically fixed, (if we discount Gold’s abiogenic hypothesis) but of course when people refer to biofuel they generally mean freshly fixed carbon using say last years sunshine instead of borrowed permian sunshine.
I just love wood gas, I feel there is an overlooked revolution here. Worldwide, charcoal is a huge source of energy, especially in africa. Primitive methods of making charcoal discard the 40% of total energy of the wood that is in the wood gas. Capturing that gas from efficient kilns and using it to run generators would supply enough electricity to match the total electrical production of those countries. I could see some kind of deal where utilitiies work with small-scale charcoal producers to accept biomass, give them their charcoal free, and payoff is in woodgas.