CO2 Burial Schemes Get Green Light

"I've worked on analyses where I've said, 'Let's make wild assumptions about the progress of renewables and whether we still need CCS,' and I think the answer is we do," Forbes added.

But others disagree.

Misplaced Energy?

Emily Rochon of Greenpeace International in Amsterdam, Netherlands, said their calculations show emissions targets can be met through developing renewable energy sources and improving energy efficiency while phasing out coal.

"The problem with CCS is that it will completely derail efforts to get off coal," Rochon said. "It's not going to be any easier 30 years from now to make the transition to renewables. It's not going to be any faster. And by then, it's probably too late."

Rochon is the lead author on a Greenpeace report published earlier this month arguing against CCS.

Rochon points out that coal brings with it many environmental costs besides CO2: "Even if CCS can ameliorate CO2, we're still going to be blowing the tops off of mountains and dumping the tailings."

"One of the better articulated arguments against CCS is that it prolongs a coal economy and that there are big problems with the coal economy," Friedmann concedes. "There are just people who don't like coal. The best argument against that is, 'Are you prepared to triple the cost of electricity to fix the climate problem?' If you aren't, we need this option."

The Technology Is One Thing

Rochon also worries that industry's pledges to build plants that are "capture ready" -- suitable for installing equipment to capture CO2 once economics or regulations drive action -- provide no guarantee that the technology will ever be used.

Since CCS adds a large cost to coal combustion, there is little incentive for power plants to push forward until CO2 emissions cost something, said civil and environmental engineer Michael Celia, of Princeton University in Princeton, NJ.

"Right now we don't know if carbon is going to have a price and what that price may be," Celia said. "Until those are given much more certainty it's hard to imagine that much is going to go forward."