Dynamotive Energy Systems uses pyrolysis (gasification) of wood waste to produce syngas, bio oil and char. The syngas is used to fuel the process. The bio oil is sold as a fuel and the char is used to enhance soils. Because wood is used the process is carbon neutral and when char is spread on fields the process becomes carbon negative. In short, this is a way to sequester to carbon. Source.
For a complete report on biochar read here.
What is different about biochar is that the stability of the charcoal should make it possible to lock away the carbon it contains for hundreds of years. The carbon is mineralised, so it’s very resistant to breaking down. What’s more, the ancillary benefits – not just its soil-improving characteristics, but certain byproducts of its manufacture – should be enough to make it economically attractive.
When it’s made, about a third of the biomass is turned to char, a third is turned to syngas that can be burned to generate electricity, and a third into a crude oil substitute that could be very useful in making plastics, though it would be hard to use as a transport fuel. Tim Flannery, the eminent Australian explorer and naturalist , argues that these properties of biochar “allow us to address three or four critical crises at once: the climate change crisis, the energy crisis, and the food and water crises”, because putting biochar in the soil not only fertilises the soil, but also helps it to retain water.