Capturing carbon: The Vattenfall coal-fired power plant uses oxygen and a series of steps to recycle the carbon dioxide. The result is a highly concentrated carbon-dioxide waste stream that makes it easier to capture the emissions.
The opening of the plant divided environmental groups in Europe. Some regard CCS technology as a potentially valuable weapon in the battle against climate change, while others see it as an expensive distraction from the pursuit of cleaner renewable-energy technologies.
But the plant was greeted warmly by CCS specialists. For Stuart Haszeldine, a geologist from the University of Edinburgh, in Scotland, it was “a very welcome, and tangible, statement that CCS can be made to work.” The European Union wants a further 10 to 15 CCS plants in operation by 2015, he points out.
“Only by actually building plants like this can poorly known costs and risks be better understood and enable the routine deployment of CCS, which so many politicians and energy analysts perceive to be essential for climate cleanup,” says Haszeldine. “This is the first; the world now needs lots more.”
Oxyfuel is one of three possible CCS technologies. Another uses a scrubbing process to try to capture carbon dioxide in the flue gases emitted after coal has been burned in a conventional power plant. The third involves gasifying the coal, creating hydrogen for generating electricity and carbon monoxide, from which carbon dioxide can be formed and separated.
According to Howard Herzog, a chemical engineer at MIT Laboratory for Energy and the Environment and manager of MIT’s carbon-sequestration
initiative, it’s too soon to say which of the clean-coal technologies will be the best. The opening of the oxyfuel plant–which he attended in Germany–was “exciting” because it represented “a significant step forward in developing CCS technology,” he says. “Vattenfall’s pilot plant will not only develop oxyfuel combustion technology; it will also provide critical information on the potential of oxyfuel combustion as a CO2-capture technology.”