I'm not so sure that "in situ" slash and char of scrub on a large scale would be totally beneficial environmentally! - did you ever see a charcoal burner's mound smoking? That's why the "in vessel" pyrolysers, which have acid gas scrubbing and NOx removal, are favourite. Algae seemed better because it grows so d***ed quick and can be used to absorb CO2 both directly from fossil fuel power plants and, in ponds, from the atmosphere. With this implementation, the use of oil rich algae would not be necessary - just a high residual "dry weight" - it wouldn't matter if it was cellulose, carbohydrate or oil... The resulting charcoal "sand" or "dust" could be ploughed into marginal land reducing nitrogenous fertiliser input etc. I don't know what effect it would have on already fertile land...
Nick Palmer
