We noticed you're browsing in private or incognito mode.

To continue reading this article, please exit incognito mode or log in.

Not an Insider? Subscribe now for unlimited access to online articles.

Sustainable Energy

Carbon-Dioxide Storage with Less Earthquake Risk

Underground rocks that react with carbon dioxide to form minerals could offer a safe way to keep the greenhouse gas from reaching the atmosphere.

Many experts expect carbon capture and storage to play a large role in reducing emissions.

There is increasing concern that storing carbon dioxide in underground rock formations could cause earthquakes that would allow it to escape, raising doubt that the strategy could play its expected role in slowing the harmful accumulation of the greenhouse gas in the atmosphere. But new research suggests that storing carbon in one particular type of underground rock could significantly reduce the risk.

A study published this month in Geophysical Research Letters suggests that storing carbon dioxide underground in a type of volcanic rock called reactive mafic rock could potentially present little seismic risk, because the surface of mafic rock reacts with carbon dioxide to form a solid mineral.

In the case of “mineral sequestration,” says David Bercovici, a professor of geology and geophysics at Yale University and an author of the new paper, “you are making rocks out of (the carbon dioxide). It’s not sitting there as a high-pressure fluid,” as would be the case with the storage rocks that are conventionally proposed. The newly formed minerals could help counter the conditions that lead to earthquakes.

Carbon capture and storage, or CCS, consists of techniques for capturing carbon dioxide emitted by fossil-fuel power plants and certain industrial facilities before it reaches the atmosphere, compressing it, and then burying it deep underground, where in theory it could be sequestered permanently in large geological formations. The International Energy Agency has said that CCS will be needed to achieve over one-fifth of the emissions cuts required by 2050 to maintain a decent chance that the global average temperature won’t rise more than 2 °C (see “The Carbon Capture Conundrum”).

The most commonly proposed storage receptacles are large porous rocks that lie deep below the earth’s surface. Candidates include depleted oil and gas fields, unmineable coal seams, and large formations called deep saline aquifers, so called because their pores contain brine.

However, a National Research Council report released last year said that while the earthquake risks are difficult to assess, “large-scale CCS may have the potential for causing significant induced seismicity.” Two Stanford University researchers went a step further, arguing in PNAS that the risk of induced earthquakes, even small ones, makes CCS a “likely unsuccessful” strategy for significantly reducing emissions (see “Researchers Say Earthquakes Would Let Stored CO2 Escape”).

Bercovici and his coauthor, Viktoriya Yarushina, a postdoctoral researcher at Yale, developed a relatively simple mathematical model that describes certain geophysical consequences of pumping carbon dioxide into underground porous mafic rock at different rates. The model, which the researchers designed to “cover a range of unknowns that we don’t have a handle on yet,” shows that “if you can balance it right so that you are causing the reactions to kind of keep pace with the rate that you’re pumping, then you could probably avoid an earthquake for a long time,” says Bercovici.

Mafic rock is the most common rock by volume on the planet, in large part because one type of it, basalt, makes up the seafloor. In fact, some researchers are investigating the possibility of storing carbon beneath the ocean. There are also a fair number of large underground mafic formations around the world which could be practical for CCS, though they are not as widely dispersed and are thus generally less accessible to power plants than are the reservoirs traditionally proposed.

But investigation into storage in mafic rock is at an early stage, and there are many unknowns regarding how it might work in practice. Much of the research now is aimed at better understanding the mineralization reactions that can occur naturally in the various types of mafic rock. “Any sort of engineering-level investigation of that process is in the future, and it’s absolutely crucial,” says Peter Kelemen, a professor of geochemistry at Columbia University.

Be the leader your company needs. Implement ethical AI.
Join us at EmTech Digital 2019.

Register now
More from Sustainable Energy

Can we sustainably provide food, water, and energy to a growing population during a climate crisis?

Want more award-winning journalism? Subscribe to Insider Plus.
  • Insider Plus {! insider.prices.plus !}*

    {! insider.display.menuOptionsLabel !}

    Everything included in Insider Basic, plus the digital magazine, extensive archive, ad-free web experience, and discounts to partner offerings and MIT Technology Review events.

    See details+

    Print + Digital Magazine (6 bi-monthly issues)

    Unlimited online access including all articles, multimedia, and more

    The Download newsletter with top tech stories delivered daily to your inbox

    Technology Review PDF magazine archive, including articles, images, and covers dating back to 1899

    10% Discount to MIT Technology Review events and MIT Press

    Ad-free website experience

You've read of three free articles this month. for unlimited online access. You've read of three free articles this month. for unlimited online access. This is your last free article this month. for unlimited online access. You've read all your free articles this month. for unlimited online access. You've read of three free articles this month. for more, or for unlimited online access. for two more free articles, or for unlimited online access.