American Supercritical has closed a pre-seed funding round of $8 million to bring factory-built, installation-ready supercritical CO2 (sCO2) power blocks to market. The round was led by Silent Ventures, with participation from Riot Ventures, Harpoon, Reveille VC, Hillwood, Mana Ventures, Climate Capital, and Alumni Ventures. The Denver-based startup is emerging from stealth with a technology that can turn any simple-cycle gas turbine into a combined-cycle plant — without modifying the existing turbine and without requiring new permits.
The concept is straightforward. An sCO2 block is installed at the turbine’s exhaust, where it captures heat that would otherwise be vented into the atmosphere and converts it into additional electricity. According to the company, the system can boost a plant’s output by up to 50% without burning any additional fuel. Simple-cycle gas turbines waste roughly one-third of their fuel as exhaust heat: the United States alone operates around 140 gigawatts of such turbines, representing tens of gigawatts of recoverable capacity. Compared to conventional steam-based solutions, the sCO2 system has a dramatically smaller footprint — roughly one-tenth the size of an equivalent steam system.
Supercritical CO2 — maintained above its critical temperature and pressure — behaves as a hybrid between a liquid and a gas, with high density and thermodynamic properties that make it more efficient than steam in certain power cycles. The technology has been studied for years at U.S. national laboratories, but commercial deployment has been slow to materialize. Matt Carlson, co-founder and CTO of American Supercritical, spent a decade working on these systems at Sandia National Laboratories, Heliogen, and Kairos Power. The broader team includes engineers from Echogen, Hanwha, Blue Origin, Southwest Research Institute, and Google X.
From a nuclear industry perspective, the platform’s versatility is its most compelling feature. The same sCO2 block designed for gas turbines is intended to integrate with small modular reactors (SMRs), geothermal plants, concentrated solar power, and industrial waste heat recovery. The company estimates a combined potential of tens of terawatt-hours per year across these sources. For SMRs — where the compactness of the power conversion system is often just as critical as the reactor itself — an sCO2 cycle of this scale could be a natural fit, particularly for projects targeting rapid deployment on space-constrained sites.
American Supercritical has opened a 25,000-square-foot facility in Denver for testing and small-series production. The company is actively hiring engineers specializing in turbomachinery and power electronics. With the capital raised, it aims to demonstrate the system at full scale and launch its first commercial sales. If the technology delivers on its promises, the sCO2 cycle could become the go-to thermal conversion module for the next generation of compact nuclear plants.
