Chinese Coal City Uses Flooded Mines to Cool Homes With Geothermal Energy

The eastern Chinese city of Xuzhou has launched a residential cooling program that draws water from the flooded Woniushan Coal Mine, a former coal-producing site in Jiangsu province. The mine water maintains a steady temperature of about 19 degrees Celsius year-round, allowing it to absorb heat from homes through a closed-loop heat-exchange system before returning underground. The pilot project, which began on June 1, currently serves 100 households in a neighborhood near the mine.

Xuzhou has a decades-long mining history and previously used water from the abandoned Hanqiao Coal Mine for district heating during winter. The new cooling initiative extends that approach to summer months, aligning with China's national "dual carbon" targets to peak emissions by 2030 and reach carbon neutrality by 2060. Zhang Tao, who leads the project at Xukuang Heating Company, told state broadcaster CCTV that the system consumes no energy and produces no carbon emissions during the heat-exchange process.

Domestic media reports indicate that such closed-loop geothermal systems reduce energy consumption by roughly 50 percent compared with traditional air conditioning. The city estimates the pilot will cut carbon dioxide emissions by about 50 tons annually across the 100 participating homes. Residents received two free months of cooling, after which the service is billed quarterly at 4 yuan (approximately $0.60) per square meter.

One resident, identified only as Wang, said her previous summer electricity bills often exceeded 400 yuan per month due to air conditioner use. Under the pilot, she paid 410 yuan total for four months of cooling and noted that her home now maintains a constant temperature around the clock without the noise of conventional units.

Zhang said the current system uses only a portion of the Woniushan mine's capacity and that the company plans to expand the network to additional neighborhoods in the future. The approach relies on rainwater accumulation and groundwater seepage that naturally fill disused mines, creating a stable thermal reservoir that can be tapped for both heating and cooling.

The project demonstrates a practical reuse of industrial infrastructure in a region transitioning away from coal production. By leveraging existing flooded shafts, the city avoids the drilling costs typically associated with geothermal installations while addressing rising cooling demand as average temperatures increase.

Officials have not disclosed the total volume of water available in the Woniushan mine or the maximum number of households the system could ultimately support. The long-term thermal stability of the mine water under continuous extraction and reinjection also remains under observation.

If the pilot proves scalable, the model could be replicated in other former mining cities across China that face similar climate and infrastructure conditions.