Underwater rocks could be used for massive carbon storage on America's East Coast

Jeremy Hance

mongabay.com

January 05, 2010

Considering it is unlikely that global carbon emissions will start dropping anytime soon, researchers are beginning to look at other methods to combat climate change. One of these is to hook polluting power plants up to massive carbon sinks where instead of the carbon going into the atmosphere it would be stored away in rocks. The process is known as carbon capture and storage or CCS. But before one can even debate the pros and cons of setting up CCS, scientists must see if high-quality sites exist.

Today, researchers writing in the Proceedings of National Academy of Sciences (PNAS) have announced a number of locations in the East Coast of the United States that appear prime for CCS. The potential sites—off Long Island, Massachusetts, and northern New Jersey—are deep under the sea bed in basalt rock, which researchers say has many advantages over other rocks, such as sandstone.

"We would need to drill them to see where we're at," said David S. Goldberg, lead author and geophysicist at Columbia University's Lamont-Doherty Earth Observatory, in a press release. "But we could potentially do deep burial here. The coast makes sense. That's where people are. That's where power plants are needed. And by going offshore, you can reduce risks."

The biggest concern with such sequestration methods is leakage of CO2, but researchers say that these sites should largely mitigate that risk. Not only are the sites deep underwater, but they are also covered over by hundreds to thousands of feet of sediment, both barriers to leakage. The gas would be pumped into the basalt, filling in the rock's gaps by displacing sea water.

"The basalt itself is very reactive, and in the end, you make limestone," explained coauthor Dennis Kent, also of Columbia University's Lamont-Doherty Earth Observatory, in a press release. "It's the ultimate repository."

According to the researchers, a patch of basalt measuring seven cubic kilometers, such as the one under New Jersey's Sandy Hook Peninsula, has the capacity to hold nearly a billion tons of carbon. That is equal to forty years of emissions from four 1-billion-watt coal plants.

Critics of carbon capture and storage argue that the technology is still unproven and that leaks are possible. Also, the process of carbon capture and storage requires additional energy usage, ultimately driving further consumption of fossil fuels instead of weaning the world off its addiction to fossil fuel energy. Most environmentalists prefer clean energy, such as wind, solar, and geothermal.