Researchers say Earthquakes Would Let Stored CO2 Escape

This MIT Technology Review article summarizes a new PNAS paper that examines one of the CCS risks that our geologist friends have been hammering on. From the abstract:

We argue here that there is a high probability that earthquakes will be triggered by injection of large volumes of CO2 into the brittle rocks commonly found in continental interiors. Because even small- to moderate-sized earthquakes threaten the seal integrity of CO2 repositories, in this context, large-scale CCS is a risky, and likely unsuccessful, strategy for significantly reducing greenhouse gas emissions.

Seismic sites: The dots on this map represent seismicity activity during March 2011, according to the United States Geological Survey. Red dots stand for seismicity induced by the creation of water reservoirs. Zoback et al. / PNAS

The authors of a paper published today in the Proceedings of the National Academy of Sciences say that large-scale carbon capture and storage (CCS) is unlikely to work because it would trigger earthquakes that could free the trapped greenhouse gas from the ground.

The paper is a blow to hopes that sequestration could become a big part of future climate strategy. The lead author of the paper is Stanford researcher Mark Zoback, a well-respected expert on the seismic risks of oil and gas production. Steven Gorelick, a Stanford hydrologist, is coauthor with Zoback.

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The paper comes just a few days after a report on the earthquake risks posed by various energy technologies, including oil and gas extraction, wastewater disposal, geothermal power, and CCS, was published by the National Research Council. That report said that “CCS may have the potential for significant seismic risk” and added that “insufficient information exists to understand this potential.”

Zoback and Gorelick’s paper notes that if CCS is to significantly affect atmospheric greenhouse-gas accumulation, it must be able to contain about 3.5 billion tons of carbon dioxide per year worldwide—an amount similar in volume to the nearly 30 billion barrels of oil the world produces annually.