This is an excerpt from EERE Network News, a weekly electronic newsletter.

March 11, 2009

Electric Industry Examines Adding Solar Energy to Coal Plants

The electric power industry plans to develop advanced coal-fired power plants that can capture their carbon dioxide emissions and sequester them underground, but that technology remains years away from commercialization, and it will probably have limited value for coal-fired power plants that are operating today. With that in mind, the Electric Power Research Institute (EPRI) and a number of utilities are now studying the potential to add solar power to existing power plants in order to help cut their greenhouse gas emissions. EPRI will work with Tri-State Generation & Transmission Association, Inc. and Progress Energy to evaluate the potential to add solar thermal energy systems to the utilities' power plants in Prewitt, New Mexico, and Roxboro, North Carolina. EPRI is also studying the potential to add solar thermal energy systems to natural-gas fired power plants owned by Dynergy Inc. and NV Energy and located in Kingman, Arizona, and Las Vegas, Nevada.

The EPRI concept involves building fields of mirrors adjacent to a power plant to focus the sun's heat and boil water into steam. The steam from these solar thermal fields would be integrated into the steam cycle of the fossil-fueled power plant to either reduce its use of fossil fuel or to increase the plant's power production. The approach would lower the carbon intensity of the power produced at the plant, while the solar thermal system could help meet state requirements for the use of solar power. Solar thermal research engineers at DOE's Sandia National Laboratory and National Renewable Energy Laboratory (NREL) will help to analyze the performance of the hypothetical solar energy systems. See the EPRI press releases on the natural gas and coal projects, as well as the related Tri-State press release.

In some ways, combining solar thermal and fossil-fuel energy in one system is an old concept, as the most of the Solar Energy Generating System (SEGS) power plants in California use natural gas as a backup energy source. Currently, the California Energy Commission (CEC) is reviewing a proposal by the City of Palmdale to build a new power facility similar to the EPRI concept, with a solar thermal facility providing 10% of the peak power generated by a 570-megawatt natural gas-fired power plant. If approved, the Palmdale Hybrid Power Project will start operating in 2013. Last year, the CEC approved a similar project in Victorville that will integrate 50 megawatts of solar thermal energy into a 563-megawatt natural gas-fired power plant. A recent DOE-funded report found that it even makes sense to combine coal-fired power plants with wind power facilities. See the data on the SEGS plants from NREL, the CEC Web pages on the projects in Palmdale and Victorville, and the coal-wind hybrid report from DOE's Lawrence Berkeley National Laboratory (PDF 296 KB). Download Adobe Reader.