World's first CO2-molten salt power plant breaks ground in China

China has started construction on the world's first utility-scale power plant to pair supercritical carbon dioxide generation with large-scale molten salt energy storage. The Ruitan project, rising at a coal-fired power station in Yantai in eastern China's Shandong province, is designed to demonstrate how the two emerging technologies can work together to reduce energy wastage and improve the stability of the electrical grid.

The concept is straightforward: when electricity demand is low, surplus power is used to heat molten salt, which stores the energy as heat. When demand spikes, that heat is released to drive a turbine using supercritical CO2, a state where the gas behaves like both a liquid and a gas, to generate electricity more efficiently than traditional steam turbines. By pairing storage with generation, the plant aims to smooth the peaks and valleys that plague modern grids. Supercritical CO2 cycles are typically more compact and efficient than steam cycles, and molten salt is already used in concentrated solar power plants to store heat for hours.

The project fits into China's broader push to modernize its power system as renewable energy grows. Wind and solar output is inherently variable, and grid operators need ways to absorb excess generation and release it on demand. Coal plants, which still supply a large share of China's electricity, are increasingly being retrofitted with storage and efficiency upgrades to make them more flexible. The Ruitan project is a test bed for that transition, using an existing coal station's infrastructure to lower the cost of the demonstration.

If the demonstration succeeds, the combination could offer a template for other countries with large coal fleets and rising renewable penetration. Molten salt storage is already proven at scale in solar thermal plants, but coupling it with supercritical CO2 generation is new. The technology could also be applied to nuclear plants, industrial waste heat, and other heat sources, giving utilities a low-cost way to add storage without building separate battery farms. That versatility is what makes the project more than a niche experiment.

The project is still under construction, and the economics of supercritical CO2 turbines are not yet proven at utility scale. Developers will need to show that the system can operate reliably, maintain efficiency over thousands of charge-discharge cycles, and compete with lithium-ion batteries, which have seen dramatic cost declines. For China, the stakes are high: the country is both the world's largest emitter and the largest builder of renewable energy, and grid stability is a top priority as intermittent sources take a bigger share of the mix.

Beijing has been pushing provincial governments to invest in energy storage, with mandates requiring new renewable projects to include storage capacity. The Ruitan project is part of that policy push, and its location at a coal-fired station is deliberate: it allows the plant to use existing grid connections, cooling water, and other infrastructure, reducing the cost of the demonstration. If it works, similar retrofits could be rolled out across China's coal fleet, turning aging plants into flexible energy hubs rather than stranded assets.

For energy executives and investors, the project is a signal that China is serious about hybrid thermal-storage systems as a complement to batteries. It also highlights the growing importance of supercritical CO2 technology, which has been studied for decades but has yet to reach commercial scale. Companies developing CO2 turbines or molten salt systems should watch the Ruitan project closely, as a successful outcome could open a large market for retrofits and new builds.

The Ruitan project is still years from completion, and many technical hurdles remain. But it represents a concrete bet on a future where coal plants are not just generators but flexible energy hubs, storing heat and dispatching power on demand. For a world struggling to balance reliability and decarbonization, that is a bet worth watching.