Carbon Dioxide Turbomachinery to Revolutionize Solar Power Generation


A research facility supported by both the American public and private sectors announced that it has successfully created and tested full-scale turbomachinery to operate the world’s first-ever supercritical carbon dioxide (SCO2) power system for a concentrated solar power (CSP) generation facility.

Supported by the APOLLO Program of the US Department of Energy, the Southwest Research Institute (SWRI) in San Antonio, TX developed the SCO2 turbomachinery to significantly improve the performance of CSP plants and to reduce the cost of electricity that these generate.

The SCO2 turbomachinery was developed in tandem with South Korea’s Hanwha Power Systems, an energy equipment company headquartered in Changwon but with a global reach.

According to Institute researchers, they have successfully completed performance and endurance tests on the turbomachinery within closed-loop conditions. Testing parameters included operating the turbomachinery under full-scale compressor conditions, as well as full-pressure and full-temperature testing of the turbine at conditions of up to 720 °C and 275 bar.

Is There a Difference Between Conventional Carbon Dioxide and SCO2?

Yes, as SCO2 may be said to be carbon dioxide in an altered state. To make SCO2, carbon dioxide is subjected to pressure and held above a critical temperature. This causes the compound to remain in a gaseous state yet have the density of a liquid. 

In such a state, this supercritical compound is highly conductive, has a high density, low viscosity, and is capable of transferring heat, making it especially efficient when it comes to power generation. 

Unlike unaltered carbon dioxide, SCO2 is both non-toxic and non-flammable. In heavy industry, it is used for low-GHG refrigeration systems. In a non-industrial context, it is commonly used for dry cleaning as well as decaffeinating coffee.

A Revolutionary Innovation

According to the team behind the breakthrough, the creation of the turbomachinery is expected to advance grid-scale energy storage, a development that will eventually lead to the more widespread use of renewables in power generation.

SWRI’s Dr. Jason Wilkes manages its rotating machine dynamics section and he opines that the increased efficiency of the SCO2 cycle will also result in a far smaller carbon footprint for power generation, approximately 1/20 of that of a standard steam turbine. The compact size of the turbomachinery will also make for easier installation.

SCO2 turbomachinery is expected to improve the efficiency of CSP plants by as much as 10%. It may also be considered to improve the performance of other industrial applications.