China's green transition underpinned by coal 'backup'

Since 2005, China has accelerated the development of renewable energy generation, with wind and solar power as the leading contributors. Today, one out of every three kWh of electricity produced in China comes from renewable sources, of which wind and solar power account for approximately 20 percent of the total electricity supply. This proportion already surpasses the global average, Wang said.

By the end of June 2025, the total installed capacity of renewable energy in China had reached 2,160 gigawatts, accounting for over 40 percent of the global total. Meanwhile, the combined installed capacity of wind and solar power had reached 1,670 GW, representing nearly half of the world's total, according to a report from the Ministry of Ecology and Environment.

However, Wang stressed, the sun doesn't shine at night, and the wind doesn't always blow, yet electricity demand is constant. "The grid must deliver power whenever users need it, day or night," he said. "Renewables alone cannot guarantee that reliability."

Globally, this intermittency is often managed by flexible natural gas-fired power plants, which have much smaller carbon emissions, he said.

However, this solution is not scalable for China. Natural gas-fired power plants account for only about 5 percent of the country's power generation capacity, limited by scarce domestic supply, high import costs, and competing priorities for residential and industrial use.

He noted that hydropower, largely designed for run-of-the-river generation in China, is poorly suited for on-demand regulation due to its dependence on seasonal and upstream water flows. Furthermore, nuclear power is predominantly a baseload power source and is not suitable for flexible load control.

"Historically, the task of providing flexible regulation for China's power grid has fallen to coal-fired power plants," Wang said.

What also underpins the indispensable role of coal-fired power in China is the high proportion of hydropower in the country's energy mix, he said. A severe or prolonged drought could trigger a hydropower shortfall that other renewable energy sources might not be able to offset quickly enough, potentially leading to supply instability.

In 2024, hydropower accounted for 14.1 percent of China's electricity generation, according to a report from the China Electricity Council.

The age of China's infrastructure also dictates its policy. While the average Western coal plant is 50 years old and nearing natural retirement, China's fleet is barely a decade old. These are modern, high-efficiency assets that represent billions of dollars in investment. Rather than discarding them, China is pursuing "clean transformations", such as co-firing with hydrogen or ammonia, which could eventually bring coal emissions down to levels comparable to natural gas. This technological pathway allows China to keep its grid stable while progressively lowering its carbon footprint.

Wang emphasized that the core principle of China's energy strategy is that, while some growth in coal power capacity may occur, efforts must focus on actively minimizing its actual use and prioritizing new energy sources for power generation whenever possible.

He likened coal-fired plants to a heavy-duty laborer who steps in only when other sources, such as solar and wind, are unable to work.

Coal-fired power plants in China are usually designed with an annual utilization of 5,500 hours. According to the China Electricity Council, however, their average annual utilization stood at only 4,628 hours in 2024.

Wang noted that as the cost of renewable energy generation in China continues to decline, steady progress has been made in enhancing the stability of renewable power systems, while electricity demand-side management is also improving its ability to adapt to evolving dynamics.