Specialist in Energy and Natural Resources Policy
Carbon capture and sequestration (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 would likely depend, in part, on the cost of the technology deployed to capture CO2. This report summarizes prospects for improved, lower-cost technologies for each of the three current approaches to CO2 capture: post-combustion capture; pre-combustion capture; and oxy-combustion capture. CRS Report R41325, Carbon Capture: A Technology Assessment, provides a more detailed analysis of these technologies.
While all three approaches are capable of high capture efficiencies (typically about 90%), the major drawbacks of current processes are their high cost and the large energy requirements for operation. Another drawback is that at present there are still no full-scale applications of CO2 capture on a coal-fired or gas-fired power plant; these plants produce over a third of total U.S. CO2 emissions from fossil fuel combustion. However, 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 precombustion 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.
The future use of coal in the United States will likely depend on whether and how CCS is deployed if legislative or regulatory actions curtail future CO2 emissions. Congressional interest in CCS was renewed when the U.S. Environmental Protection Agency (EPA) re-proposed standards for carbon dioxide (CO2) emissions from new fossil-fueled power plants on September 20, 2013. These re-proposed standards would not apply to existing power plants. As re-proposed, the standards would limit emissions of CO2 to no more than 1,100 pounds per megawatt-hour of production from new coal-fired power plants and between 1,000 and 1,100 for new natural gasfired plants. According to EPA, new natural gas-fired stationary power plants should be able to meet the proposed standards. However, new coal-fired plants only would be able to meet the standards by installing CCS technology, which could add significant capital costs.
In general, the focus of most current R&D activities is on cost reduction rather than additional gains in CO2 capture efficiency. Key questions include: when would advanced CO2 capture systems be available for commercial rollout; and how much cheaper they would be compared to current technology. “Technology roadmaps” developed by governmental and private-sector organizations anticipate that CO2 capture may be available for commercial deployment at power plants by 2020. Some roadmaps also project that some novel, lower-cost technologies may be commercial by 2020. Such projections acknowledge, however, that this will require aggressive efforts to advance promising concepts to commercial viability.
Date of Report: November 5, 2013
Number of Pages: 12
Order Number: R43300
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