Thursday, October 2, 2008

A University of Calgary research team developed a new method for extracting carbon dioxide (CO₂) directly from the air — a fundamental shift in carbon capture technology enabling capture of the most common greenhouse gas from so-called diffuse sources like aircraft, trucks and automobiles that represent half of the greenhouse gases emitted globally.

Professor David Keith, Director of University of Calgary’s (UofC) Institute for Sustainable Energy, Environment and Economy (ISEEE) and a team of researchers from UofC’s Energy and Environmental Systems Group built and operated a prototype system this summer producing results that compared favourably with commercial carbon capture systems. Two ‘provisional’ patents have been filed on the technology but Keith warns there are still “many pitfalls along the path to commercialization.”

Using a process adapted from the pulp-and-paper industry that halves the cost of CO₂ air capture in their custom-built tower, Professor Keith and his team captured the equivalent of about 20 tonnes per year of CO₂ (approximately equal to the yearly output of one person in North America) directly from the air with less than 100 kilowatt-hours of electricity per tonne of carbon dioxide on a single square metre of scrubbing material.

“This means that if you used electricity from a coal-fired power plant, for every unit of electricity you used to operate the capture machine, you’d be capturing 10 times as much CO₂ as the power plant emitted making that much electricity,” explains Professor Keith.

A report co-authored by Keith in the American Chemical Society’s journal Environmental Science & Technology explains “nearly all current research on carbon capture and storage (CCS) focuses on capturing CO₂ from large, stationary sources such as power plants. Such plans usually entail separating CO₂ from flue gas, compressing it, and transporting it via pipeline to be [stored] underground.”

Using CO₂ air capture technology, “a company could, in principle, contract with an oil sands plant near Fort McMurray to remove CO₂ from the air and could build its air capture plant wherever it’s cheapest — China, for example — and the same amount of CO₂ would be removed,” says Professor Keith in a UofC press release.

“While it’s important to get started doing things we know how to do, like wind power, nuclear power, and ‘regular’ carbon capture and storage,” Professor Keith continues, “it’s also vital to start thinking about radical new ideas and approaches to solving this problem.”

ISEEE’s Executive Director David Layzell points out that “energy-efficient and cost-effective air capture could play a valuable role in complementing other approaches for reducing emissions from the transportation sector, such as biofuels or electric vehicles.”