Unlocking Low-Grade Heat in China to Power Lanzhou’s Clean-Heating Transition

 Every city produces wastewater. Few recognise it as a strategic energy resource.

In Lanzhou, China, winter heating demand in the city’s Chengguan District has long outpaced available capacity. As the city continues to grow and conventional heat sources reach their limits, Lanzhou faced a critical question. How could it secure reliable winter heating while meeting China’s increasingly stringent clean-energy and decarbonisation requirements?

Rather than expanding carbon-intensive infrastructure, Lanzhou Thermal Power Group pursued an alternative path. Treated wastewater, generated daily across the city, retains residual thermal energy from industrial and residential use. When recovered and upgraded through high-efficiency heat pump technology, this low-grade heat can be converted into a dependable, low-carbon source of district heating.

Working with Johnson Controls, Lanzhou Thermal Power Group transformed this underutilised urban resource into a stable, scalable heating solution. This wastewater-heat district heating project, the first of its kind in Gansu Province, now provides reliable winter heating to approximately 1.5 million square metres of residential buildings. Its emissions reduction impact is equivalent to planting 1.6 million trees each year, supporting Lanzhou’s clean-heating and dual-carbon objectives.

As Chinese cities accelerate their low-carbon transition, the ability to unlock value from existing infrastructure is becoming a defining capability. Lanzhou’s experience shows how circular energy thinking can strengthen energy security, improve urban resilience, and deliver tangible public benefit.

The future of clean heating is already here. Is your city ready?