Biochar (charcoal) - Eco friendly or next disaster?

Hi all

I came across something on t'internet earlier about the latest buzzword to do with saving the planet. That word is 'biochar'.

Basically, it is charcoal, but with the oils and gases captured during production rather than just evaporating away.

Here's the general idea from what I gather: In a suitably built kiln, we heat waste biomass to high temperature, without letting oxygen in. As the gases escape from the biomass, some of which is highly flammable, we direct it into the stove, so once started, the process effectively powers itself. When it finishes, ie when the biomass is reduced to charcoal, we dig that charcoal into the ground, where it improves water and nutrient retention, attracts worms, and sequesters carbon from the atmosphere, so the result is apparently improved ground for growing stuff, all done cheaply and using a process that is ultimately carbon negative.

Now I'm interested in stuff like this, but I'm a skeptic. I saw what a mess resulted from the last brilliant idea of using biofuel, when rainforest was cleared for more lucrative palm oil plantations, and food prices went up because areas formerly used for food production were used for other fuel crops. The biochar thing is supposed to be different though. It is supposed to reduce deforestation by keeping existing crop land healthy, thus negating the need to clear more forest.

The ever efficient Germans are taking it very seriously. They've built a trial plant that will take raw sewage and process it in this way, and they are studying the effect of adding the resulting charcoal to poor soil, but its all still in its early stages.

Has anyone else heard or read of this?