Earthquakes will release captured carbon: Stanford study

Shake, rattle, roll, leak

Carbon capture and storage (CCS) won’t work, according to a study published in the Proceedings of the National Academy of Sciences, because underground earthquakes are certain to cause the carbon to be released too soon.

That’s the gloomy prediction of a group of Stanford University scientists, and a blow to those seeking engineered solutions to climate change.

The problem is twofold. CCS proposes injecting CO₂ into brittle underground rocks, something that has geologists increasingly worried could trigger earthquakes (although last Friday, while admitting the risk exists, the US National Research Council noted that no data exists on the risk because there are no large-scale CCS projects in operation).

Second, whether the earthquakes are triggered by the CCS project or not, nearly every continental interior suffers quakes of some magnitude over time scales of decades. The huge volume of CO₂ that would need to be stored – around 3.5 billion tons per year, if CCS is to be viable – means that repositories would be needed all over the world.

A quake at any repository would lead to a CO₂ leak – but for CCS to work, leak rates need to be in the order of a percent every thousand years, the study states.

“In this context, large-scale CCS is a risky, and likely unsuccessful, strategy for significantly reducing greenhouse gas emissions,” the authors, Mark Zoback and Steven Gorelick of Stanford’s departments of Geophysics and Earth System Science, write. ®