Thread: Greenhouse gas disaster?

New Scientist 15 February page 36.

A proposal to create lots of gas for energy. Turns out that the most common fossil fuel is coal, and no more than 30% of coal beds are accessible to conventional mining, due to cost, hazards etc. For example, there are extensive coal beds under shallow seas. But this proposal will permit extraction of energy in vast amounts from these difficult coal beds.

If you burn coal, in the middle of a coal bed, with minimal oxygen, the heat of combustion will also drive off lots of volatile and flammable gases. These can be extracted by sucking them up a pipe, and then a suitable refinery can turn them into useable methane and other materials. So the plan is to drill pipes into the inaccessible coal beds. Air is pumped down one pipe, and the coal set afire. Other pipes suck up the volatiles.

Obviously this will make vast amounts of the greenhouse gas, CO2. So they plan to pump the CO2 back down into the area which was coal, but is now open due to the coal being burned. They even suggest the volatiles be burned to generate electricity, and the waste CO2 sent back down into the coal bed.

What do you guys think of this plan?

What are we going to do when all the coal runs out?

Whatever the plan is, why don't we just do that to begin with?

Originally Posted by skeptic

If you burn coal, in the middle of a coal bed, with minimal oxygen, the heat of combustion will also drive off lots of volatile and flammable gases. These can be extracted by sucking them up a pipe, and then a suitable refinery can turn them into useable methane and other materials. So the plan is to drill pipes into the inaccessible coal beds. Air is pumped down one pipe, and the coal set afire. Other pipes suck up the volatiles.

They've been doing this for 50 years in Centralia, PA. It didn't turn out so well for them.

What are the net GHG emissions and climate implications? I don't see anything to suggest that this is about replacing higher emissions coal or other high emissions fuels, it's in addition to coal use and other fossil fuel extraction. The proposed pumping of CO2 down to the coal beds looks more like it's intended to maximise gas extraction as part of maximising the use of fossil fuels, not maximise emissions mitigation.

Has the climate problem ceased to be a consideration in the minds of those making these proposals - or never been a critical consideration? Is the climate problem solely seen as a problem because it represents an obstacle to the business plans of those making such proposals - a problem they address by support for climate science denial PR, tankthink and donations to obstructionist politics?

I haven't read the paywalled full article but they are right to question the wisdom of setting fire to underground coal seams to force out gas in a warming world.

The CO2 deposition solution that they suggest will not work. How are they going to prevent collapses when the coal burns away and the now unsupported roof of the seam weakens and collapses. Any collapse will release all the "sequestered" CO2 immediately.