The Future of CCS: Still a Turbid Sky

Several reports of great stature predict the future development of carbon capture and storage (CCS). The IPCC Special Report on Carbon Dioxide Capture and Storage (2005), the Stern Review on the Economics of Climate Change (2006) by the British government, and MIT’s The Future of Coal: Options for a Carbon Constrained World (2007) all state that CCS can be employed safely at a large scale. The only gaps in knowledge noted by these reports relate to monitoring and verification, and the only unresolved issues are the development of regulations and long term liability.

Despite positive projections by the experts, some questions remain. An example of general skepticism can be found in the article “Important! Why Carbon Sequestration Won’t Save Us” at treehugger.com. Some of the author’s criticisms of CCS are not likely to be fatal flaws. To be fair though, I don’t think the author claimed to have any expertise. The only source cited was Tim Flannery’s book The Weather Makers, not exactly a treatise on CCS. The author’s broader concern, however, cannot be easily brushed aside. The article voices concern over the possibility that token amounts will be invested in CCS in a effort to buy time for continued investment in coal rather than renewable sources of energy. Whether CCS is practicable, or whether it is a significant distraction, a diversion, or a red herring (but probably not an ignoratio elenchi) is an issue that deserves debate.

Rau and Caldeira have a different concern (”Coal’s Future: Clearing the Air” in Science 4 May 2007). They feel that CCS is prematurely being treated as the most viable of the “clean coal” technologies. They point out that post-combustion chemical or biological uptake of CO2 from the air, combined with conversion of the CO2 into stable chemical forms would avoid some of the drawbacks of CCS. Namely, such forms of CO2 emissions mitigation would avoid the large energy cost of capturing, concentrating, compressing, transporting, and injecting CO2 into the subsurface. In addition, removing CO2 from the air and mineralizing it would be a much more cost effective way to deal with emissions from existing coal-fired power plants.

Carbon emissions from coal to liquids facilities are even more problematic, even when carbon is captured during the conversion process. Here is a brief overview.

NRDC presents a policy package aimed at clearing the air. In “No Time Like the Present: NRDC’s Response to MIT’s ‘Future of Coal’ Report”, NRDC advocates CO2 emissions standards for all new power plants. The standards could resemble California’s SB 1368 (2006), which places emissions standards on all electricity providers who contract to sell power in California even if the generation is out-of-state. Alternatively, the standard could be similar to a renewable portfolio standard (RPS). Instead of mandating a percentage of all electricity be generated from renewable sources, a low carbon generation standard would only mandate a level of GHG emissions, not the method by which the emissions are avoided. The standard would be set low (perhaps 20%) during the initial period, then gradually increased. Crediting emissions avoidances would be tradable. Thus, electricity providers could meet the standard by investing in renewable electricity generation, coal-fired generation with CCS, removal of CO2 from the air, or by purchasing credits from other firms that made such investments.

NRDC argues that either of these policy packages would initiate competition to determine which of the GHG emissions mitigation technologies are most viable. There would be incentive to either immediately deploy CCS or drop it like it’s hot.