Earth Day 2025, which falls on Tuesday, promotes the use of renewable energy to "triple clean electricity."
China has been decarbonizing its power system by not only increasing consumption of renewable sources but also by painstakingly tackling emissions caused by coal power.
Shanxi Province in north China has long been a coal hub in the country. What takes place in its power plants provides insight into the nationwide energy transition in the country.
COAL PLAYING SUPPORTING ROLE
The Tashan power plant, a coal-fired facility located in the city of Datong in Shanxi, operates at only a fraction of its capacity during the morning hours. At 11 a.m., the electronic screen in the monitoring room indicates that one of the plant's two 600-MW coal-fired generation units is producing just 180 MW -- allowing more space for solar and wind power on the grid.
Several workers closely monitor the screen, which updates the power price every 15 minutes. This price fluctuates between zero and 1.5 yuan (about 20.8 U.S. cents) per kWh."During daylight hours in good weather, when renewable energy sources generate abundant electricity, power prices can drop to nearly zero. In such cases, we need to adjust the operational parameters to keep our output at the lowest possible level," said Fan Jiangbo, shift supervisor in the monitoring room.
"However, when dusk falls and peak hours begin, solar output decreases and power prices rise. Then we need to quickly increase our generation, not only to take advantage of the higher prices but also to ensure stability of the power grid," Fan added.
What happens in the monitoring room at Tashan power plant offers a glimpse into the nationwide endeavor to boost the consumption of renewables in the process of power generation. It also highlights the changing role of coal power -- shifting from being the major source of power generation to a baseload and flexibility provider.
"Due to the volatility of power generated from renewable sources, coal power will continue to play a supporting and guarantee role in ensuring energy security for a certain period," an official from China's National Development and Reform Commission (NDRC) stated at a press briefing held last year.
In China, since energy storage capacity has not yet kept pace with the increase in solar and wind power, the grid still relies on thermal power to ensure a stable electricity supply, said Wang Bing, an associate professor at China University of Mining and Technology-Beijing, in an interview with Xinhua, in explaining why thermal power is indispensable for now.
According to a white paper titled "China's Energy Transition" issued last year, China phased out over 100 million kilowatts of outdated coal power capacity in the space of a decade.
By operating its generators at a capacity of 180 MW, a new low in its 17-year history, the Tashan power plant provided 420 MW of grid capacity for solar and wind power. "We should yield as much capacity as possible to new energy generation," Fan noted.
This breakthrough has been made possible by both technological retrofitting of coal-fired power units, to enable a more flexible load regulation, and viable price incentives.
Price incentives are in place, with Shanxi having established the country's first operational electricity spot market by the end of 2023. This spot market enables electricity to be traded at real-time prices based on fluctuating demand, encouraging coal-fired power plants to operate accordingly -- thereby boosting the consumption of solar and wind power.
DECARBONIZING COAL POWER
Decarbonizing existing coal-fired power plants presents another pressing task, as China has committed to peaking its carbon dioxide emissions by 2030 and achieving carbon neutrality by 2060.
The Tashan power plant is running a combined heat and power (CHP) project, harnessing thermal energy generated alongside electricity to supply steam to surrounding factories and heat residential buildings in the city of Huairen in the north of Shanxi.
Wang identified the CHP project as pursuing one of the goals for the current stage of decarbonizing coal-fired power plants. In the long run, more technologies will be applied in the low-carbon retrofitting of coal-fired power plants.
Last year, the NDRC and the National Energy Administration (NEA) jointly issued an action plan for low-carbon retrofitting of coal power facilities in the 2024 to 2027 time frame.
This year, the low-carbon retrofitting of coal power facilities has also been included in the government work report -- underscoring the importance that policymakers attach to this approach.
The action plan outlines three technological pathways, namely biomass co-firing, ammonia co-firing and carbon capture. Wang stated that these three low-carbon technologies are currently mostly in trial phases, but all hold commercial prospects, particularly biomass co-firing due to the availability of resources.
As the national carbon market matures, commercial prospects will improve, as additional costs associated with adopting these new technologies will be partly offset by revenue generated by sales of carbon emission allowances.
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