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CO2 Burial Schemes Get Green Light

Jessica Marshall, Discovery News

How It Works

Capturing CO2 from industrial processes can be done in a few ways. Most commonly the gas from combustion passes through a liquid containing amines that absorb the CO2.

The CO2 is then separated and compressed into a "supercritical fluid" that behaves much like a liquid. From there, the CO2 is transported to sequestration sites along pipelines. Some of these already exist for transporting CO2 for enhanced oil recovery, but widespread CCS would require a much bigger network.

The CO2 is injected at least a kilometer or so underground. At that depth, the temperature and pressure are high enough that the CO2 will remain in the supercritical, liquid-like state.

The key to making it stay down there is choosing the right site. The CO2 needs to be injected into porous rock layers that have room for it, but below impermeable layers that can act as a cap to keep the CO2 trapped beneath.

One of the concerns has been whether such sites may leak.

"I am not worried about leaks with proper regulation and siting," said Ken Caldeira of the Carnegie Institution of Washington in Stanford, Calif.

But, he adds, "The incentive to the industry will be to put the CO2 in the cheapest, easiest place, which may not be the best place. So it all depends on good regulation and enforcement."

Waiting Game

Although the Greenpeace report cites sources saying CCS won't be practically available until 2030, others suggest that the reasons for the delay are political and regulatory, not technical.

"All of the major technologies needed for this are available. If there were a serious political will to make this happen, it could happen in the near term," Celia said.

But Rochon said such efforts would come at the cost of funding for renewables, which should be a higher priority.

"The concern with the cost of CCS is the fact that industry is asking the government to fund it and that therefore it takes away from funding for renewables," she said.

Friedmann, Forbes and Celia agree that efforts in renewables and efficiency are just as important, but, Celia said, "We need many solutions."

"There's been growing awareness that there really is a climate crisis," Friedmann added. "And we need to fire on all pistons quickly."

U.S. Department of Energy

World Resources Institute

Discovery Earth Live

Planet Green