Advanced science.  Applied technology.


SwRI, GTI Energy, GE celebrate mechanical completion of $155 million supercritical CO2 pilot plant

October 27, 2023 — Southwest Research Institute (SwRI®), GTI Energy, GE Vernova (GE) and the U.S. Department of Energy celebrated the ribbon-cutting of the Supercritical Transformational Electric Power (STEP) Demo pilot plant today. The $155 million, 10-megawatt supercritical carbon dioxide (sCO2) test facility at SwRI’s headquarters in San Antonio will demonstrate an innovative new method of higher-efficiency, lower-cost electric power generation.

“STEP will undoubtedly change the way we think about power generation,” said SwRI President and CEO Adam Hamilton, P.E. “It’s exciting to officially launch this pilot plant, which is home to potentially revolutionary technology developed right here at SwRI.”

“We are excited to collaborate with our partners through the STEP Demo pilot project to showcase the benefits of supercritical carbon dioxide technology for power production,” said Dr. Paula A. Gant, President and CEO, GTI Energy. “This innovation is set to deliver cost-effective, highly efficient, and transformative benefits.”

Unlike conventional power plants, which use water as the thermal medium in power cycles, STEP is designed to use high-temperature sCO2, which increases efficiency by as much as 10% due to its favorable thermodynamic properties. Carbon dioxide is nontoxic and nonflammable, and when CO2 is held above a critical temperature and pressure, it can act like a gas while having the density near that of a liquid. The sCO2 power cycle technology is also compatible with concentrated solar power and industrial waste heat.

“STEP Demo represents a shift toward more sustainable and efficient power generation, which has only been possible because of the ingenuity of the remarkable team that has supported this project at every stage,” said Dr. Tim Allison, director of SwRI’s Machinery Department.

One advantage to using sCO2 as a working fluid is that STEP Demo’s turbomachinery is approximately one-tenth the size of conventional power plant components, making it possible to shrink the footprint and construction cost of any new facilities. For example, STEP Demo’s desk-sized sCO2 turbine could power up to 10,000 homes.

SwRI, GTI Energy, and GE broke ground on the STEP Demo site on October 15, 2018, and building construction was completed in 2020. The pilot plant achieved its first operation of its compressor with CO2 at supercritical fluid conditions earlier this year. Commissioning of the facility will continue through early next year.

The STEP Demo pilot plant is one of the largest demonstration facilities in the world for sCO2 technology. The project’s central goal is to dramatically improve the efficiency, economics, operational flexibility, space requirements and environmental performance of this new technology. SwRI, GTI Energy, and GE collaborated on the design of the plant, which is specially conceived to evolve over time to keep pace with industry advancements. The facility’s skid-mounted components provide flexibility and a unique, reconfigurable design.

SwRI is an industry leader in the development of sCO2 power cycles. Staff members have conducted numerous U.S. Department of Energy projects advancing the efficiency, reliability and commercial readiness of sCO2 power cycle turbomachinery, heat exchangers, cycles and systems. The team brings extensive experience with sCO2 technology and the key building blocks to make the STEP Demo project a success and a landmark demonstration.

For more information, visit STEP Demo Pilot Plant or contact Joanna Quintanilla+1 210 522 2073, Communications Department, Southwest Research Institute, 6220 Culebra Road, San Antonio, TX 78238-5166.