China builds new CO2 and molten salt power project

September 22, 2026

China has started construction on what is described as the world’s first utility-scale project combining supercritical carbon dioxide (sCO2) power generation with molten salt energy storage. The demonstration facility is designed to capture surplus energy, improve power plant flexibility and help stabilize the electricity grid as renewable energy capacity expands.

The Ruitan demonstration project is being built at China Huaneng’s Bajiao power station in Yantai, Shandong province. Construction began in September, with the facility expected to enter operation next year.

Turning surplus electricity into stored heat

The project will use excess electricity from the power station’s existing coal-fired generating units during periods of low electricity demand.

Instead of allowing this surplus energy to go unused, electricity will be converted into thermal energy and stored by heating molten salt held in large storage tanks.

When electricity demand rises, the process will be reversed. Heat stored in the molten salt will be transferred to a supercritical carbon dioxide power system, which will generate electricity for the grid.

The first phase is planned to include a 50-megawatt supercritical CO2 power unit alongside a 100MW/400MWh molten salt energy storage system.

How supercritical CO2 power generation works

Conventional thermal power stations typically burn fuel to heat water, producing steam that spins a turbine connected to an electricity generator.

Supercritical CO2 technology takes a different approach.

Carbon dioxide is maintained above its critical temperature and pressure, creating a dense fluid with properties of both a gas and a liquid. This supercritical CO2 can drive a turbine before circulating through a closed-loop system for reuse.

Compared with conventional steam-based equipment, sCO2 technology can enable more compact power generation systems while eliminating the need for water in the turbine cycle. It also has the potential to deliver higher conversion efficiency.

Another important advantage is flexibility. Supercritical CO2 turbines can rapidly adjust their output between minimum and maximum operating levels, making the technology potentially valuable for electricity grids with growing amounts of variable wind and solar power.

According to Chinese state media, the adjustment rate can be around four times that of conventional coal-fired generating units.

Supercritical CO2 can use multiple heat sources

The technology does not depend exclusively on fossil fuels. Heat required for an sCO2 power cycle can potentially come from several sources, including concentrated solar power, geothermal energy, nuclear energy and industrial waste heat.

China has already demonstrated the technology commercially.

Chaotan One, located in Guizhou province, began commercial operations at the end of last year. Instead of burning additional fuel, the system uses waste heat generated by a steelmaking facility to produce electricity through a supercritical CO2 cycle.

Why molten salt is important for energy storage

Molten salt storage works differently from conventional batteries.

Lithium-ion and other electrochemical batteries store electricity as chemical energy. Molten salt systems instead convert surplus electricity or captured heat into thermal energy, which can remain stored in insulated tanks until it is needed.

That thermal energy can later be used to generate electricity or supplied directly to industrial and heating applications.

Battery storage remains highly flexible and is suitable for applications ranging from electric vehicles to grid-scale installations. Molten salt, however, can provide advantages for large stationary projects where storing substantial quantities of thermal energy for several hours is required.

Combining molten salt with supercritical CO2 technology could therefore provide another option for long-duration energy storage and flexible power generation.

China expands development of sCO2 technology

China is pursuing several projects involving supercritical carbon dioxide.

China National Nuclear Corporation, which developed the Chaotan One system, has also launched a project designed to integrate molten salt thermal energy storage with supercritical CO2 electricity generation. The initiative is expected to advance toward integration by 2028.

Similar concepts are under development outside China.

In Europe, the SOLARSCO2OL project has explored combining molten salt-based concentrated solar power with supercritical CO2 technology. The objective is to improve the efficiency, flexibility and economic performance of solar thermal electricity generation.

Potential applications beyond conventional power plants

Supercritical CO2 systems are also attracting attention for advanced nuclear energy applications.

Because the technology can operate in a compact, closed-loop configuration without relying on a conventional steam turbine, researchers are examining its potential for future nuclear power systems, including highly compact reactors and possible space-based applications.

Meanwhile, China is expanding the use of molten salt storage in renewable energy projects.

A molten salt storage system is being incorporated into the 50MW Dangxiong concentrated solar power plant under construction in the Tibet autonomous region.

Once completed, the facility is expected to use solar energy collected during daylight hours to heat molten salt. The stored thermal energy can then be used to generate electricity when solar production declines or electricity demand increases.

A new approach to flexible energy storage

The Ruitan project represents an effort to combine two emerging technologies in a single utility-scale system: large-scale molten salt thermal storage and supercritical CO2 power generation.

If the demonstration performs as planned, the approach could provide power systems with another method of storing surplus energy and releasing it during periods of high demand.

The technology could also eventually be paired with renewable, nuclear, geothermal and industrial heat sources, expanding its potential role beyond conventional fossil-fuel power stations.

As electricity systems incorporate increasing amounts of intermittent renewable generation, technologies capable of efficiently storing energy and responding rapidly to changes in demand could become increasingly important for maintaining grid reliability.