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Carbon capture and sequestration (or carbon capture and storage, CCS) is widely seen as a critical strategy for limiting atmospheric emissions of carbon dioxide (CO2)—the principal “greenhouse gas” linked to global climate change—from power plants and other large industrial sources. This report focuses on the first component of a CCS system, the CO2 capture process. Unlike the other two components of CCS, transportation and geologic storage, the CO2 capture component of CCS is heavily technology-dependent. For CCS to succeed at reducing CO2 emissions from a significant fraction of large sources in the United States, CO2 capture technologies would need to be deployed widely. Widespread commercial deployment will likely depend, in part, on the cost of the technology deployed to capture CO2. This report assesses prospects for improved, lowercost technologies for each of the three current approaches to CO2 capture: post-combustion capture; pre-combustion capture; and oxy-combustion capture.
While all three approaches are capable of high CO2 capture efficiencies (typically about 90%), the major drawbacks of current processes are their high cost and the large energy requirements for operation. Another drawback in terms of their availability for greenhouse gas mitigation is that at present, there are still no full-scale applications of CO2 capture on a coal-fired or gas-fired power plant (i.e., a scale of several hundred megawatts of plant capacity). To address the current lack of demonstrated capabilities for full-scale CO2 capture at power plants, a number of large-scale demonstration projects at both coal combustion and gasification-based power plants are planned or underway in the United States and elsewhere. Substantial research and development (R&D) activities are also underway in the United States and elsewhere to develop and commercialize lower-cost capture systems with smaller energy penalties. Current R&D activities include development and testing of new or improved solvents that can lower the cost of current postcombustion and pre-combustion capture, as well as research on a variety of potential “breakthrough technologies” such as novel solvents, sorbents, membranes, and oxyfuel systems that hold promise for even lower-cost capture systems.
In general, the focus of most current R&D activities is on cost reduction rather than additional gains in the efficiency of CO2 capture (which can result in cost increases rather than decreases). Key questions regarding the outcomes from these R&D efforts are when advanced CO2 capture systems will be available for commercial rollout, and how much cheaper they will be compared to current technology. “Technology roadmaps” developed by governmental and private-sector organizations in the United States and elsewhere anticipate that CO2 capture will be available for commercial deployment at power plants by 2020. A number of roadmaps also project that some novel, lower-cost technologies will be commercial in the 2020 time frame. Such projections acknowledge, however, that this will require aggressive and sustained efforts to advance promising concepts to commercial reality.
Achieving significant cost reductions will likely require not only a vigorous and sustained level of R&D, but also a significant market for CO2 capture technologies to generate a substantial level of commercial deployment. At present such a market does not yet exist. While various types of incentive programs can accelerate the development and deployment of CO2 capture technology, actions that significantly limit emissions of CO2 to the atmosphere ultimately are needed to realize substantial and sustained reductions in the future cost of CO2 capture.