Arthur Dahl's Blog at International Environment Forum
Underground Coal Gasification
Arthur Lyon Dahl
If you are worried sick about greenhouse gases from fracking (hydraulic fracturing of oil shales) which are already being added to the fossil carbon from traditional oil and coal, with proven reserves five times the remaining capacity of the atmosphere to absorb CO2 before runaway global warming begins, stop reading now. The next great discovery of the coal industry is underground coal gasification (UCG). A report by Fred Pearce, "Beyond Fracking" (New Scientist, 15 February 2014, pp. 36-41), describes UCG now being planned or tested around the world, based on a plant in operation in Uzbekistan for the last 50 years. The idea is to set fire underground to coal deposits that are not economical to mine, inject air down, and pump the resulting hydrogen, methane and carbon dioxide to the surface to use as fuel. This is estimated to meet our energy needs for the next thousand years, so the coal industry loves it. There are plans to go commercial by 2015. Of course, this is worse than fracking, and will add at least 10°C more to global warming, but that does not worry the proponents, who can solve energy security problems and make money quickly.
There are other environmental concerns as well. Pilot plants in the USA and Australia were shut down after carcinogenic benzene and toluene leaked into groundwater. The voids left by burned coal could lead to subsidence. Even putting out the fires for decommissioning could be a problem. Some accidental fires in underground coal have burned for years.
At a time when climate scientists say we need to leave 80% of existing fossil fuel reserves in the ground, plans to burn the other 80% of coal that is beyond reach seem suicidal. Unfortunately this is a working technology that could make lots of money. Have we ever said no?
Last updated 11 March 2014