Heat Recovery District Heating Schemes Pick Up Pace in Europe

Across Europe, new district heating schemes are gaining traction. The city of Stirling, Scotland recently launched a new district heating network that harnesses wastewater heat to provide heating to numerous public buildings and businesses. The project is expected to save around 381 tons of carbon a year and will soon be expanded to residential housing.

London is also using pioneering applications of heat recovery to create sustainable district heating systems. The city is using heat from its Underground transit system to heat residential homes. By the end of 2019, heat from the subway is expected to heat 450 additional homes in north London. These homes will join 700 others in the Islington network that are already heated using waste heat from the Underground through the Bunhill Energy Centre.

Beyond the UK

Elsewhere in Western Europe, Copenhagen, Denmark inaugurated a new ammonia heat pump that serves 1,100 households in April 2019. The pump takes heat from wastewater and seawater and is powered by electricity. The system runs on ammonia, a natural refrigerant with a zero-carbon footprint. Adoption of this pump is growing in large HVAC system applications. Tokyo, Oslo, and Vancouver are some of the other cities already using wastewater heat recovery.

These projects are all part of plans that cities have for reducing carbon emissions. Copenhagen, for instance, aspires to be the first carbon-neutral capitol in the world by 2025. London is striving to become carbon-neutral by 2030. As these targets approach, these projects and others are paving the way for more heat pump and heat recovery applications in district heating systems across Europe and beyond.

Potential for Reduced Emissions

District heating and cooling in cities hold significant potential for curbing emissions and improving air quality. Legacy district energy systems around the world, including in China, Russia, Eastern Europe, and Latin America, are prime for retrofits that reduce the consumption of coal and natural gas and transition toward renewable energy sources. Heat recovered from subways, wastewater, and refrigeration and various industrial processes can meet a significant portion of heating demand. Even without significant upgrades, compared with competitive technologies, district energy is more cost-effective than individual buildings producing their own heating or cooling in dense urban environments.

Innovative business models and systemwide cooperation in cities are needed to capture this opportunity. Integration of electricity and heat generation and a wide range of heat waste sources offer exciting opportunities for district energy providers to reposition themselves in the market. Political leadership and general awareness of sustainable district energy technologies remain low. However, new models are possible, as demonstrated by the Stockholm Open District Heating network. Companies that produce excess heat, such as supermarkets or data centers, can sell it on the open network at market prices. Models like this can address the challenges vendors face with integrating city energy systems.