The Fuzzy Math of Carbon Capture

by RP Siegel (American Energy Society) ... But when (Peter) Eisenberger talks about a sustainable economy, he’s talking about supplementing the work of trees by capturing the greenhouse gas from, say, the smokestack of a coal-fired power plant, or even directly from the air, and then burying it underground or using it for manufacturing plastics or biofuels. It’s a complex engineering problem — and a concept that’s fraught for those demanding action on climate change. Scrubbing CO2 out of an industrial facility’s emissions could slow the transition from fossil fuels to cleaner energy sources. At the same time, the added expense would also drive energy prices up.

The U.N. Intergovernmental Panel on Climate Change has, for years, included so-called “carbon dioxide removal” (CDR) technologies among its list of tools to combat warming — and it labeled them as essential in its most recent reports.

Among CDR technologies, only so-called “direct air capture” can claim to be fully carbon negative — with the potential of sopping up more of the greenhouse gas than even trees. The others, like smokestack removal, are largely carbon neutral.

Global Thermostat is one of three companies that are pioneering the effort to make the challenging technology involved in direct air capture of carbon financially viable.

This spring, one of Global Thermostat’s competitors announced that it has a path to bring that price tag down to $94 per ton. Carbon Engineering, a Canadian outfit, plans to turn captured CO2 into synthetic hydrocarbon fuels. When founder David Keith described the company’s plans, scientists hailed the proposal as an important breakthrough. But Eisenberger, Global Thermostat’s chief technology officer, says his company can go even lower. He says that his firm has “irrevocably shown that a price of $50 per ton is achievable.” The first step to getting there is a substantial deal the company negotiated with a major soft drink manufacturer.

Still, there are those who see direct-air capture as not really ready for prime time, especially when compared with options such as planting more trees, carbon farming, and sucking carbon out of fossil fuel plants’ smokestacks (another cost-intensive process that Global Thermostat can do with retrofits). The IPCC notes in its latest report that deploying the technology at a scale where it could contribute to keeping warming well below 2.7 degrees Fahrenheit is “still a considerable challenge.” “The thing about direct-air capture is that it’s one of the less technologically developed solutions out there,” says Matt Lucas, associate director of the Oakland, California-based nonprofit Carbon180 (formerly the Center for Carbon Removal). “It has quite high technology risk.” READ MORE