What if scientists could transform coal-fired power plants from giant carbon dioxide emitters into giant carbon sinks? Some say that they can, and will. Graciela Chichilnisky, a founder of Global Thermostat, admits it's hard to believe: "The more energy the less the emissions—it's mind boggling."
Global Thermostat and at least two competitors say they can pull carbon dioxide straight from the air, potentially at costs low enough to solve global warming and provide an infinite source of gas by using the CO2 to feed algae. Chichilnisky summarizes her company's business model this way: "Take CO2 from the air and turn it into cash."
As a technical matter the idea is clearly possible. Expensive machines used in submarines and space craft have been pulling CO2 out of the air for generations. The trick is making sucking CO2 out of the air economically feasible. In practice that means beating the cost of carbon capture and sequestration, which typically run $50 per ton.
Traditional chemical engineering thinking says: good luck with that. The difficulty of separating out one type of gas gets exponentially greater the lower its starting concentration. The concentration of CO2 in the air is growing but still thin on a relative basis, roughly 400 parts per million. By contrast, the CO2 that's possible to capture as its emitted from power plants, which today is often captured and sequestered, is often 300 times more concentrated.
But the companies all say they have cracked that problem by building low-cost systems for grabbing and concentrating atmospheric CO2. One trick is to use the waste heat from a coal plant or other industrial sources to power the carbon capture.
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