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This article is from the In-Depth Report A Guide to Carbon Capture and Storage

Carbon capture and storage: Absolute necessity or crazy scheme?

Does the world really need the ability to trap carbon dioxide before it invisibly billows from power plant smokestacks or out car tailpipes and bury it permanently to slow global warming? You bet, argued some environmentalists, academics and corporate executives at a carbon capture and storage (CCS) conference held at Bloomberg headquarters yesterday in New York. Among the reasons: China (the world's leading emitter of carbon dioxide) will need it, the technology already exists and if we don't get a handle on ever-rising greenhouse gas emissions, climate change will reach catastrophic proportions.

"The reason that we believe CCS is a critically important part of the toolbox is there's a huge gap between what can technically do and what we are doing, and part of that is politics," said David Hawkins, director of the climate center at the Natural Resources Defense Council (NRDC). He  said that 30 states either mine coal or burn it for the majority of their electricity and therefore support technology that would allow that to continue even as the nation reduces CO2 emissions.

Yet, at the same time and in the same city, the Sierra Club and other environmental groups were protesting the New York Coal Trade Association's annual conference, proclaiming  that "Coal kills" by, for example, emitting the heavy metal mercury, a neurotoxin, when it is burned. CCS is, in large part, a lifeline for burning coal in a world trying to avoid the CO2 emissions such coal burning produces in copious quantities. The good news is that the technology—and technical know-how—to do something about the roughly 40 percent of manmade CO2 emissions that come from burning coal already exists. Whether it's adding chemical scrubbers to existing coal plants or building entirely new ones that gasify the coal before burning it (allowing the CO2 to be separated out), industrial plants using the same technology have already been built.

There are at least four projects underway worldwide that are storing CO2 deep underground today. Norway with two is leading the charge, thanks to a carbon tax that works out to about $50 per metric ton of CO2. Both projects separate CO2 from natural gas (before said gas is sold into the world market) and pump the CO2 back underground to get more gas out as well as permanently store the ubiquitous greenhouse gas. With 30-plus years of data collected, these projects and others demonstrate that CO2 is safely stored in the earth without significant leaks.

"Once down there, it can't all come out because of physics and it's quite reliable," Susan Hovorka, a geologist at the University of Texas, who has run her own CCS experiments, said at the conference.

All four projects combined, however, only add up to roughly .006 percent of U.S. CO2 emissions—and the U.S. now pumps out less CO2 than China, though individually, or per capita, Americans are among the world leaders in emitting the greenhouse gas. Plus, neither of the Norwegian projects nor the ones in North Dakota and Algeria are tied to an actual coal-burning power plant.

At present, there are two such power plants in the world—one in China that is under construction and a small one in Germany that separates out the CO2 to store it in an abandoned natural gas field. Adding such CCS technology to coal plants tacks on roughly $65 per metric ton of CO2 to the cost of electricity, according to Howard Herzog, a research engineer at the Massachusetts Institute of Technology (M.I.T.), who also noted that it will take at least seven years until a commercial scale CCS power plant could even be built in the U.S., because of legal issues, permitting and the length of construction.

That said, there is urgency to the task, according Gardiner Hill, head of environmental technology at oil giant BP, which is participating in the CCS project in Algeria. "For every five years of inaction, it requires an extra gigaton of reductions," he said. And that urgency—plus U.S. and global political realities—are pushing even environmentalists to back CCS for coal.

"There are many challenges associated with coal," including mercury pollution, residual toxic coal ash, water consumption, mining practices and worker safety, admitted Mark Brownstein, managing director of business partnerships in the climate and air program at Environmental Defense Fund. But "we have to deal with coal in order to achieve the kind of reductions we need to make in the timeframe we need to make them."

Photo of decommissioned Athlone Power Station, Cape Town, South Africa, by DanieVDM via Flickr

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