Advanced science.  Applied technology.

SwRI, industry collaborators receive $8.5 million from U.S. Department of Energy to develop high-efficiency hot gas turbo-expander for solar plants

For immediate release

San Antonio — July 26, 2012 — Southwest Research Institute and industry collaborators General Electric, Bechtel Marine Propulsion Corporation and Thar Energy LLC have been awarded an $8.5 million contract by the U.S. Department of Energy to develop a high-efficiency supercritical CO2 hot gas turbo-expander for concentrating solar power plants. The award was given through DOE's SunShot Initiative, a collaborative national effort to make solar energy cost competitive with other forms of energy.

Because of the highly cyclical nature of concentrating solar power (CSP) plant operation, a supercritical CO2 (sCO2) hot gas turbo-expander must be able to operate at high temperatures and pressures over a wide range of load conditions while maintaining a high efficiency, handle rapid transient heat input swings and have very fast start-up capabilities to optimize the plant's online availability.

"Over a three-year period, SwRI and its industry collaborators will design and develop a highly efficient, single or multi-stage sCO2 hot gas turbo-expander that will advance the state-of-the-art from laboratory size (technology readiness level 3) to a full TRL6 mega-watt scale prototype," said Dr. Klaus Brun, a program director in SwRI's Mechanical Engineering Division who will serve as project manager for the effort.

A second objective of the project is to optimize novel, printed circuit heat exchangers for sCO2 applications to drastically reduce their manufacturing costs. The scalable sCO2 expander design and improved heat exchanger will address and close two critical technology gaps required for an optimized CSP sCO2 power plant and provide a major pathway to achieving CSP power at $0.06 per kilowatt hour, increasing energy conversion efficiency to greater than 50 percent, and reducing total power block cost to below $1,200 per kilowatt installed.

The project, which will be conducted in three phases, is expected to begin August 2012, and will continue through 2015. In phase 1, researchers will design the expander and heat exchanger. Phase 2 will involve component fabrication and phase 3 will include performance testing.

For more information about this research at SwRI, contact Brun at or (210) 522-5449.

For more information, contact Deborah S. Deffenbaugh, (210) 522-2046, Communications Department, Southwest Research Institute, PO Drawer 28510, San Antonio, TX 78228-0510.