STEP Demo
The Supercritical Transformational Electric Power (STEP) Demo pilot plant has generated electricity for the first time using supercritical carbon dioxide (sCO2) power cycles. The $169-million, 10-MW sCO2 facility at Southwest Research Institute (SwRI; San Antonio, Tex.; www.swri.org) is demonstrating next-generation power production technology in a project led by GTI Energy in collaboration with SwRI, GE Vernova, the U.S. Dept. of Energy/National Energy Technology Laboratory and several industry participants.
For the first time, the pilot plant’s turbine achieved its full speed of 27,000 rpm at an operating temperature of 260°C and generated a small amount of power. Over the next few weeks, the STEP team will slowly ramp up the operating temperature to 500°C and generate 5 MWe of power.
After completion of this first test configuration, the STEP Demo project will enter its final phase. The pilot plant will be reconfigured to boost the power plant’s efficiency and overall energy output. This modification requires the installation of new equipment, as well as a new commission and test phase that will continue into 2025 until the pilot plant is running at full power. At the end of its final phase, the pilot plant will produce 10 MWe hourly.
Unlike conventional steam power plants, which use water as the thermal medium in power cycles, STEP uses high-temperature sCO2 to increase efficiency by as much as 10% due to its favorable thermodynamic properties (for more details, see Chem. Eng. August 2020, p. 6).