Professor Klaus Lackner, Ewing-Worzel Professor of Geophysics in the Department of Earth and Environmental Engineering at Columbia University have developed a sorbent that is “close to the ideal,” in that it uses a relatively small amount of energy to release the CO2 and is not prohibitively expensive.
“By the time we make liquid CO2 we have spent approximately 50 kilojoules [of electricity] per mole of CO2.” Compare that, Lackner said, to the average power plant in the U.S. which produces one mole of CO2 with every 230 kilojoules of electricity.
“In other words, if we simply plugged our device in to the power grid to satisfy its energy needs, for every roughly 1000 kilograms [of carbon dioxide] we collected we would re-emit 200, so 800 we can chalk up as having been successful,” he said.
The biggest cost was at the “back-end” of the collector, primarily the technology used to release the CO2 from the sorbent. He said for that reason, on a cost-basis, the “synthetic tree” could not compete with modern coal-fired power plants that are designed to release fewer carbon emissions than their older predecessors. But he said when compared to the cost of retro-fitting an existing coal plant, the “synthetic tree” becomes more viable.
“Each unit would take out a ton of CO2 a day — which would be the amount of CO2 produced by 20 average automobiles in the U.S.A. And the cost of each unit would be about the cost of a Toyota. So that would mean if you added a five percent surcharge on automobile purchases that money could go to building units to remove the CO2 those vehicles are going to create.”
The technology is not being developed as an alternative to the carbon capture and storage methods currently being tested for large-scale use on coal-fired power stations. He’s targeting carbon that’s already in the air.