World’s First 630°C Coal Unit Sets New Efficiency Record

China has achieved a milestone in coal-fired power generation. The world’s first 630°C ultra-supercritical double-reheat coal power unit — the Datang Yuncheng National Demonstration Power Project in Shandong Province — has entered full commercial operation, achieving a landmark 50.05% thermal efficiency and becoming the first coal-fired power plant globally to break the 50% efficiency barrier.

Operated by China Datang Corporation, the project’s Unit 1 completed its 168-hour full-load trial run on June 8 and reached full-capacity operation, as Xinhua News reported on July 28. The unit delivers 1,000 MW of capacity with a net coal consumption rate of just 256.28 grams per kilowatt-hour — a world record low.

Breaking the 50% Efficiency Ceiling

To understand why this matters, it helps to know how coal power plants work. Conventional coal plants burn coal to create steam that drives turbines. Standard subcritical plants operate at roughly 33–37% thermal efficiency, meaning more than 60% of the energy in the coal is lost as waste heat. Supercritical plants reach 38–42%, and previous ultra-supercritical (USC) plants typically achieved 44–48%. The 50% threshold had long been considered the practical ceiling for coal power efficiency.

The Datang Yuncheng project shattered that ceiling by operating at a main steam pressure of 35.5 MPa and a reheat steam temperature reaching 631°C — exceeding the 630°C benchmark. This leap was made possible by a suite of domestic innovations, including a newly developed C630R turbine rotor capable of withstanding extreme temperatures, advanced G115 high-temperature specialty steels, a 12-stage regenerative extraction system that maximizes heat recovery, and a variable-speed small-turbine-driven power balancing generator.

A Made-in-China Achievement

One of the most striking aspects of the project is its near-total reliance on domestic technology. The unit boasts a 98.89% localization rate across material research and development, equipment manufacturing, and engineering. This was a coordinated effort involving China Datang, Dongfang Electric, China Baowu, and the China Iron & Steel Research Institute, among others.

“Targeting technological innovation, process upgrades, equipment iteration, and material innovation, the unit achieved breakthroughs and integrated applications of ‘new technologies, new processes, new materials, and new equipment,’” said Lü Jun, Chairman of China Datang Corporation, as quoted by Xinhua. “It successfully broke through the industry technology ‘ceiling’ of 50% power generation thermal efficiency.”

The domestic supply chain achievement is particularly significant. According to a separate engineering report, China’s self-developed G115 steel — a new generation of martensitic heat-resistant steel developed over more than a decade — was applied for the first time in key components such as the main steam pipeline. This material can reduce pipeline wall thickness by one-third and weight by half compared with imported alternatives, breaking what the report described as the “technological monopoly of developed countries in the field of high-temperature resistant metal materials.”

Environmental Impact and the Clean Coal Debate

Higher efficiency means less coal burned for the same amount of electricity. According to China Datang, compared with conventional 1,000 MW units, the two units at the Yuncheng plant can save 208,000 tons of standard coal per unit annually and reduce carbon dioxide emissions by 540,000 tons per unit. The coal saved is enough to power 250,000 households for an entire year.

However, the project also reignites a longstanding debate. Critics argue that improving coal efficiency does not address the fundamental carbon emissions from coal combustion — the plant still emits CO₂, just less per unit of electricity. Some environmental advocates contend that massive investment in coal infrastructure, even efficient coal, diverts resources from renewable energy deployment at a time when the world should be rapidly transitioning away from fossil fuels.

Proponents, including the Chinese government, frame this technology as part of a “clean coal” strategy — a bridge to carbon peaking and carbon neutrality goals. China argues that as the world’s largest coal consumer with over 1,000 GW of installed coal capacity, upgrading its existing fleet to higher efficiency standards is an immediate and practical way to reduce emissions intensity while maintaining energy security.

Global Implications

China’s achievement sets a new global benchmark for coal-fired power generation and solidifies its position as the world leader in high-efficiency coal technology. The 98.89% domestic equipment rate establishes an independent supply chain for high-temperature materials, reducing strategic vulnerabilities. This technology could eventually be exported to other coal-dependent nations seeking to improve their own power generation efficiency.

The project also serves as a stepping stone. China has already begun construction of a next-generation 650°C ultra-supercritical coal power unit, aiming to push efficiency even further. The Datang Yuncheng project provides the technological demonstration and material science foundation needed to make those higher-parameter systems viable.

What to Watch

Several questions remain open. Unit 2 of the Datang Yuncheng project has yet to enter operation. The cost competitiveness of this technology compared with solar and wind power — which have seen dramatic cost declines — is not yet clear. And how China plans to deploy this technology across its existing coal fleet for retrofits will significantly determine its overall climate impact.

For now, however, the world’s first 630°C ultra-supercritical coal unit stands as a testament to what state-directed industrial innovation can achieve — and as a reminder that coal, despite its environmental drawbacks, is not standing still.