The Supercritical Transformational Electric Power (STEP) Demo pilot plant is the first facility of its kind to fire its natural gas heater and operate its turbine at an intermediate speed of 18,000 rpm. The $169 million, 10-megawatt supercritical carbon dioxide (sCO2) test facility at Southwest Research Institute (SwRI) in San Antonio is one of the largest demonstration facilities in the world for sCO2 technology.