Geothermal utilization runs both hot and cold

Xiong'an New Area is moving ahead with the construction of a green and sustainable heat supply system supported by its rich geothermal resources and waste heat, with renewable energy meeting one-fourth of its current heating needs, according to an energy executive.

Hu Wenjin, deputy general manager of China Xiongan Group Smart Energy Co, made the remarks in an interview with China Daily in the lead-up to the eighth anniversary of the new area's establishment on April 1.

He said there has been a significant transition in the utilization of geothermal resources in Xiong'an over the past eight years.

Geothermal resources were found in Xiong'an's Xiongxian county in the 1970s during well drilling for oil exploitation, according to Hu.

While the resources were quickly utilized for hot spring baths and heating, their development became disorderly. Excessive exploitation resulted in the decline of geothermal resources, causing ground subsidence, he said.

"After the new area was established, geothermal resource management has been steadily refined by both the government and businesses. Over-extraction is now unlikely under strict regulations," he added.

Hu said the utilization of geothermal resources in Xiong'an now follows a stringent principle: the amount of geothermal water extracted is determined by the volume reinjected underground, ensuring a balance between extraction and reinjection.

"The operation of the geothermal heat supply system extracts only heat from geothermal sources without withdrawing any water," he said.

This means that Xiong'an has achieved sustainable utilization of its geothermal resources, avoiding the issues that occurred in the past.

The deputy general manager said, to improve the efficiency of geothermal resource utilization, a dozen energy stations have been constructed in Xiong'an, integrating geothermal energy with natural gas in a coupled system.

In case of extreme cold weather events, heat generated from consuming natural gas will be supplemented to help ensure stable heat supply. When there is surplus geothermal heat, these energy stations will help avoid waste.

To date, middle-deep geothermal energy has been used to heat a cumulative floor area of 12 million square meters in Xiong'an. This initiative reduces carbon dioxide emissions by 100,000 tons annually, Hu said.

According to China Xiongan Group Smart Energy Co, 60 medium-deep geothermal wells and 2,360 shallow geothermal wells have been built and put into operation since the new area's establishment.

"Currently, the geothermal-heated floor area covers 27 percent of the total in Xiong'an's newly constructed zones... And the rate is expected to jump to 30 percent next year," Hu said.

He added that Xiong'an is also proactively promoting the utilization of waste heat from garbage incineration and sewage treatment, with one project using waste heat from waste-to-energy incineration for heating already in operation.

The deputy general manager noted shallow geothermal energy as a key focus for his company's future development, considering its potential to meet cooling needs.

"It can not only utilize heat under the ground for winter heating, but also harness the soil's cooling capacity for summer cooling. It's an excellent renewable and sustainable energy solution," he said.