New research suggests that carbon capture and storage (CCS) may be a far more limited climate solution than previously thought because it can induce earthquakes, which can cause CO2 leakage.
We’ve known for a long time that underground injection of massive quantities of liquids or high-pressure gases can induce earthquakes. Indeed, recent research finds that fracking wastewater reinjection has caused “a rise in small to mid-sized earthquakes in the United States.”
Concerns about earthquakes and CCS matter, as analysis by Stanford researchers made clear in 2012:
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.
Even a very small leakage rate of well under 1% a year would render the storage system all but useless as a “permanent repository”.
CCS-driven earthquakes have been mostly a theoretical concern — until now. Seismologists studied why a Texas oil field had “93 well-recorded earthquakes occurring between March 2009 and December 2010,” some of which exceeded Magnitude 3. They found a close correlation between these quakes and large-scale CO2 injections into the field.
One expert who reviewed the study before publication said:
“The bottom line here is … carbon dioxide injection under high enough pressures and with high enough volume could induce seismicity just like any other fluid at high enough pressures and with high enough volume. We see (quakes) fairly often with water injection. We know that that can often trigger seismic events and sometimes those can be quite large. So, it isn’t really a surprise that carbon dioxide injection does the same thing.”
The problem for CCS is that it requires a staggering amount of CO2 injection to make a difference as a climate solution. As BusinessWeek reported in 2008, “One large, coal-fired plant generates the equivalent of 3 billion barrels of CO2 over a 60-year lifetime. That would require a space the size of a major oil field to contain.”
But you would need to sequester the carbon from literally hundreds of coal plants to have any impact whatsoever on carbon pollution. As Vaclav Smil has explained:
“Sequestering a mere 1/10 of today’s global CO2 emissions (less than 3 Gt CO2) would thus call for putting in place an industry that would have to force underground every year the volume of compressed gas larger than or (with higher compression) equal to the volume of crude oil extracted globally by [the] petroleum industry whose infrastructures and capacities have been put in place over a century of development. Needless to say, such a technical feat could not be accomplished within a single generation.”
Not all CCS repositories may suffer from earthquake-induced leaks — but absent multiple, large-scale tests in a variety of different geologies, it will be difficult to have confidence that we know which subset of potential repositories might be viable. Yet as Climate Progress reported last month, there has been a sharp drop in large-scale integrated projects to capture CO2 from energy systems and bury it underground.
Finally, earthquake-induced leaks wouldn’t merely undercut the climate value of CCS. A 2010 Duke University study found: “Leaks from carbon dioxide injected deep underground to help fight climate change could bubble up into drinking water aquifers near the surface, driving up levels of contaminants in the water tenfold or more in some places.” What kind of contaminants could bubble up into drinking water aquifers? The study noted: “Potentially dangerous uranium and barium increased throughout the entire experiment in some samples.”
As Curt White, who had run the US Department of Energy’s CCS effort, said back in 2008, “Red flags should be going up everywhere when you talk about this amount of liquid being put underground.”