Domestic and international pressures are building rapidly on the United States to enact some form of legislation to curb greenhouse-gas emissions, as a spate of recent developments turns up the...
The Capture-Committed Power Plant
Moving coal forward requires a clear path to CCS.
Researchers are developing carbon capture and storage (CCS) technology as a means of reducing CO 2 emissions from coal-fired power plants and other large stationary sources. CCS isn’t yet commercially viable for coal-fired power plants, but some coal-plant developers claim their plants are capture ready; that is, these plants can be retrofitted to implement CCS at a later date when it’s commercially viable. This claim has created a controversy about what it means to be capture ready and whether being capture ready is an adequate approach to mitigating CO 2 emissions. The capture-committed power plant is an alternative to the capture-ready concept that should resolve some of the controversy.
CCS is a system with three basic components: capture from the source, transport of the CO 2 from the source to a geologic reservoir and storage in that reservoir. Each component of CCS has been used commercially for decades, usually independently, for purposes other than CCS. CO 2 is captured, for example, from various high-purity sources (such as chemical plants) for sale and reuse in the food industry, in oil production and in greenhouses. Pipeline networks for long-distance transport of the CO 2 are in commercial operation in several countries and CO 2 is injected deep underground into depleting oil fields for enhanced oil recovery (EOR).
Widespread use of CCS for power generation requires combining the three components of CCS into an integrated system; cost-effectively capturing CO 2 from low-purity, low pressure, power-plant sources; injecting CO 2 into new types of geologic reservoirs, notably deep saline formations; and vastly increasing the scale of use of CCS, both in individual facilities and in total. These technical issues require work to resolve, but no insurmountable technical barriers exist and many paths to their solution are being explored. The expectation is that these issues will be resolved over the coming decade.
Coal-fired power plants with CCS could be built today. Indeed, several pilot projects are already in operation and full- scale demonstration projects are under construction or planned around the world (see Sidebar, “CCS In the Works.”) CCS, however, is not yet an economic option for most commercial power- generation facilities for three reasons.
First, CCS needs further development to address technical issues, to identify and refine the best technologies, to reduce costs (especially of capture), and to demonstrate storage under diverse geological conditions. Second, the legal-regulatory framework for CCS is not yet in place, particularly as it relates to CO 2 injection and undefined long-term liability for CO 2 storage. And third, the economic value placed on reducing CO 2 emissions (for example, in CO 2 emissions-trading systems) is too low for plant developers to earn an adequate return without a higher-value market for the CO 2 such as EOR or industrial reuse.
A developer building a power plant with CCS today would be faced with a plant that would be uneconomic due