Underground carbon dioxide storage likely would cause earthquakes
Baku, June 21 (AZERTAC). The notion of mitigating harmful carbon dioxide emissions by storing the gas underground is not practical because the process is likely to cause earthquakes that would release the gas anyway, according to a commentary published Monday in Proceedings of the National Academy of Sciences. While the scientists do not expect that the approach would cause any large and dangerous seismic activity, they say it is likely that the earthquakes would be severe enough to jeopardize the ability to store the gas underground over the long term.
Some scientists and government officials have proposed dealing with human-generated carbon emissions with a process called “carbon capture and storage,” or CCS, in which the gas is separated from the emissions of a coal-burning power plant, captured, and then injected underground at high pressure.
The problem is that much of the Earth’s crust hangs in a tenuous balance, so even a slight change in underground pressure can cause small earthquakes. While these earthquakes might not knock down any buildings, they would almost certainly ruin the CCS site and return it to square one, said Mark Zoback, a geophysicist at Stanford University and an author of the commentary. “If even a small leak develops, you’ve not succeeded in doing anything for the environment,” Zoback said.
The earthquakes were not dangerous, but they were definitely caused by the change in pressure underground, the scientists reported.
The argument over whether methods that rely on underground injections of liquid and gas can cause earthquakes has been intensifying of late. Hydraulic fracturing, a process that shoots chemicals into rock formations to release natural gas, has caused particular concern because gas companies are pushing for rapid expansion of the approach.
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