(above: part of the Mechabolic)
At WorldChanging Jeremy Faludi speculates on the combined use of gasification and terra preta for the creation of carbon-negative fuel:
I can’t promise that using gasification for energy and using the resulting char as terra preta fertilizer will be a carbon negative fuel, because I haven’t seen a credible lifecycle analysis of it. (If anyone has, please post it to the comments.) But it’s quite plausible. Consider that it takes a certain amount of CO2 to grow a crop, such as corn. You harvest the crop and sell the food part, which leaves you with all the agricultural waste. Instead of burning it in the open air, or landfilling it (which is what’s done today — basically topsoil mining), you gasify it. You then burn the fuel gas you get from gasification, putting some fraction of that CO2 into the air; the agri-char (terra preta) that you’re left with contains the rest of the embodied CO2 which the crops sucked up while growing. There’s more carbon here than there was in the fuel gas. You spread the terra preta on the fields as fertilizer to grow more crops, and repeat the cycle — and with each repeat, you pull more carbon back into the soil than you burn, resulting in a carbon negative fuel as well as crops fertilized with fewer petrochemicals. It’s a double win.
A group of Burners have created a project using these principles called the “Mechabolic”:
Our intention with the Mechabolic is recast combustion machines and their related petroleum fuels –the foundations of our industrial energy economy– as somewhat of a veiled project of artificial life. Where usually a dry technical problem is seen, we want to suggest that what is really at issue here is the the “third leg” of the grand human engineering project of replicating ourselves.