EERE's New Projects

Supercritical Carbon Dioxide Turbo-Expander and Heat Exchangers

Awardee Details

Southwest Research Institute


DOE Amount 

The Southwest Research Institute (SWRI) and its partners will develop an external combustor that is capable of operating at much higher temperatures and allows for the mixing of CSP-heated air with natural gas in hybridized power plants.

The project aims to develop a supercritical carbon dioxide (s-CO2) power cycle that combines high efficiencies and low costs for modular CSP applications. The SWRI team is working to advance the state-of-the-art s-CO2 turbo-expander design from laboratory testing to full prototype demonstration.

The scalable s-CO2 expander design and improved heat exchanger close two critical technology gaps required for an optimized CSP s-CO2 power plant. Successfully developing these systems represents a major stepping stone on the pathway to achieving a levelized cost of energy of $0.06 per kilowatt-hour, and increasing energy conversion efficiency to greater than 50%.


  • Develop a novel, high-efficiency s-CO2 hot-gas turbo expander optimized for CSP applications
  • Optimize novel printed-circuit heat exchangers for s-CO2 applications to drastically reduce their manufacturing costs
  • Test the s-CO2 turbo expander and novel s-CO2 heat exchanger in a 1-MWe s-CO2 test loop
  • Demonstrate component performance and the performance of the optimized s-CO2 Brayton cycle over a wide range of partial-load conditions and during transient operations representative of a typical CSP duty cycle