Fossil fuel fired electric generating plants are the cornerstone of America's central power system. Currently, the existing fossil fuel fleet accounts for about two-thirds of all electricity generated domestically, over 30% from coal alone. Electricity demand is expected to increase dramatically over the next 30 years with the growth of the manufacturing sectors. In the meantime, the United States will continue to rely on existing plants to provide a substantial amount of affordable electric power for years to come as new capacity is added to meet demand.
Retrofitting the Existing Fleet of Power Plants
There is vast potential for retrofitting carbon capture technologies to the existing fossil fuel fleet. In 2016, coal-fired power plants produced nearly 30 percent of the total U.S. electricity. In addition, over 40 percent of the existing U.S. coal generating capacity is located directly above potential geologic sequestration sites according to the Carbon Sequestration Atlas of the United States and Canada. This includes almost 150 electric generating sites, or nearly one-sixth of the total U.S. CO2 emissions. By retrofitting CO2 capture technologies to just the coal-fired plants near geologic sinks, billions of tons of CO2 can be used to produce over 120 billion barrels of oil while permanently storing the CO2 over the remaining life of the existing fleet.
However, today’s capture technologies are not cost-effective when considered in the context of storing CO2 from existing power plants. DOE/NETL analyses suggest that today’s commercially available post-combustion capture technologies may increase the cost of electricity for a new pulverized coal plant by up to 80 percent and result in a 20 to 30 percent decrease in efficiency due to parasitic energy requirements. Additionally, advanced carbon capture technologies are necessary to reduce the cost of capture, but have not been demonstrated at scales large enough for power plant applications.
Since very little R&D has historically been devoted to carbon capture systems for existing power plants, there is significant potential to reduce the cost and energy demand of CO2 capture and compression processes through technological advancements. The Post-Combustion Capture Research area is pursuing innovative improvements in existing post-combustion CO2 capture systems and also exploring transformational new capture concepts.
Several advanced technologies and processes have been proposed that could significantly reduce CO2 capture and compression costs, compared to conventional processes. This process intensification combines CO2 capture with reduction of criteria pollutant emissions are being explored as well.
Examples of activities for this research area include:
- Research on revolutionary improvements in CO2 separation and capture technologies — new materials (e.g., non-aqueous solvents, physical and chemical sorbents, ionic liquids, carbon fiber molecular sieves, advanced cryogenic process, and polymeric membranes);
- Development of retrofittable CO2 reduction and capture options for existing large point sources of CO2 emissions such as electricity generation units;
- Integration of CO2 capture with advanced power cycles and technologies and with environmental control technologies for criteria pollutants; and
- Development of advanced technologies for CO2 compression such as "shockwave compression."