The Electric Power Research Institute (EPRI) has associated itself with two projects to test adding solar thermal energy to natural gas and coal-fired power plants.

EPRI will help electric power companies add solar energy to fossil-fueled electric power plants, reducing fuel costs and plant emissions. Dynegy Inc. and NV Energy will host case studies at their natural gas combined cycle facilities with project participants including Salt River Project, Southern Company and Progress Energy.

Both projects will involve adding steam generated by a solar thermal field to a conventional fossil fuel-powered steam cycle, either to offset some of the coal or natural gas required to generate electric power or to boost overall plant power output.

These projects will provide a conceptual design study and two detailed case studies. Design options to retrofit existing plants will be analysed and new plant design options will be identified. EPRI will rely on its expertise in solar technologies, steam cycles, and plant operation, as well as past solar and fossil plant studies. EPRI holds two patents in solar steam cycle optimisation.

The projects will be conducted in parallel, with one focused on natural gas plant technologies and the other on coal plant technologies. As part of the natural gas project, case studies will be conducted at Dynegy's Griffith Energy Facility in Kingman, Ariz., and at NV Energy's Chuck Lenzie Generating Station near Las Vegas.

Bryan Hannegan, vice president - Environment and Generation,  EPRI said these 'hybrid power plants' will combine the low-cost reliability of existing fossil power plants with the environmental benefit of renewables, and help companies meet federal and state mandates to reduce their emissions of air pollutants and greenhouse gases with renewable energy.

Referring to 27 states in the US having enacted RPS policies, EPRI mentioned that using solar to augment coal or natural gas potentially is the lowest-cost option for adding solar power to the generation fleet, as it utilises existing plant assets.

"And because the highest-intensity solar energy typically is within a few hours of peak summer loads, it makes solar augmented steam cycles a particularly attractive renewable energy option," stated the Institute.