Carbon Capture: A Technology Assessment

Carbon capture and sequestration (or carbon capture and storage, CCS) is widely seen as a critical strategy for limiting atmospheric emissions of carbon dioxide (CO 2)—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 CO 2 capture process. Unlike the other two components of CCS, transportation and geologic storage, the CO 2 capture component of CCS is heavily technology-dependent. For CCS to succeed at reducing CO 2 emissions from a significant fraction of large sources in the United States, CO 2 capture technologies would need to be deployed widely. Widespread commercial deployment would likely depend, in part, on the cost of the technology deployed to capture CO 2. This report assesses prospects for improved, lower-cost technologies for each of the three current approaches to CO 2 capture: post-combustion capture; pre-combustion capture; and oxy-combustion capture. While all three approaches are capable of high CO 2 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 CO 2 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 CO 2 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 post-combustion 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 CO 2 capture (which can result in cost increases rather than decreases). Key questions regarding the outcomes from these R&D efforts are when advanced CO 2 capture systems would be available …