China's Ruitan Project Pioneers Supercritical CO2-Molten Salt Hybrid for Grid Stability and Efficiency

China has broken ground on the Ruitan demonstration project (also referred to as Rui-Tan-Hao or 睿碳号), the world's first utility-scale facility combining supercritical carbon dioxide (sCO2) power generation with molten salt thermal energy storage. Construction began on September 16, 2026, at the existing Bajiao coal-fired power station in Yantai, Shandong province, operated by China Huaneng. The first phase includes a 50 MW sCO2 generation unit paired with a 100 MW / 400 MWh molten salt storage system, with full operation targeted for 2027 as part of a national major science and technology project on CO2 thermal battery technology.

The system stores surplus electricity from the coal plant's existing units during low-demand periods by heating molten salt. During peak demand, the stored thermal energy heats sCO2—maintained above its critical point of 31°C and 7.38 MPa, where it exhibits properties of both liquid and gas—to drive a turbine in a closed-loop cycle, replacing traditional steam. This setup enhances flexibility, enabling 0-100% load adjustment with response speeds up to four times faster than steam units, while offering higher energy density, compact size, no water requirement, greater efficiency, and reduced emissions.

Multiple independent reports confirm these details and advantages. The project retrofits an operational coal facility to minimize waste and support grid stability, aligning with China's push for technological innovation in energy systems rather than renewables alone. It builds on prior Chinese sCO2 deployments, such as the Chaotan-1 waste-heat unit in Guizhou that entered commercial operation in late 2025. Analysts note broader context: Chinese entities filed 75% of global clean energy patents by 2022 and accounted for over half of worldwide clean energy investment from 2019-2025.

Potential extensions include nuclear applications and other high-temperature sources. The hybrid approach demonstrates how targeted engineering can improve existing infrastructure's performance and adaptability.