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Euronews
21-07-2025
- Business
- Euronews
How waste heat from Hamburg's copper smelter is warming the city but not the planet
The Hafencity area, once part of Hamburg's port, is now a large urban redevelopment project. Since 2018, the buildings in eastern Hafencity have been connected to a district heating system fuelled by CO2-free industrial waste heat. The multi-metal company Aurubis and the energy supplier Enercity Contracting got together to make it work. At the time, it was the largest project of its kind in Germany, according to Enercity Contracting's managing director Dr Manfred Schüle. However, over the last few years, similar district heating systems have been developed. Nevertheless, 'this project here is still unique because we use waste heat from a source where fossil fuels have never been involved', points out Dr Schüle. Where does the CO2-free industrial waste heat come from? Just a few kilometres away from Hafencity, more than 400,000 tonnes of pure copper are produced every year at the Aurubis smelter. The waste heat is the result of a chemical process to obtain sulphuric acid, a sub-product of refining copper. The sulphur inside the copper concentrates reacts with oxygen: 'This is an exothermal reaction producing heat. So it is totally CO2-free, no gas is burnt, it's just there,' explains the director of corporate energy and climate affairs at Aurubis, Dr Holger Klaassen. Aurubis had to adapt the plant to absorb the heat and turn it into hot water. The water is then transferred to the city through the 3.7 km long pipeline network that Enercity Contracting built. First, the water needs to be pumped. This is possible thanks to a key element of the project, Enercity Contracting's energy station. In the energy station, the hot water is also stored to balance fluctuations in heat supply and demand. 'If no heat is available from our partner, we have a backup system here which can provide the heat for our customers through a boiler which can use natural gas', adds Dr Schüle. Enercity Contracting invested €8 million in the energy station, of which €2.9 million were co-financed by the European Cohesion Policy. The total budget to deliver the heat to Hafencity East was over €40 million. Aurubis and Enercity Contracting invested over €20 million each. Industrial waste heat saves up 120,000 tonnes of CO2 per year Next to the energy station, the first aid kit manufacturer Hans Hepp chose to replace its two oil boilers with the district heating, to warm its 12,000 m² facility. This was a big step for us to connect to the low-carbon heating from Enercity Contracting – we could reduce our CO2 footprint by 170 tons per year,' says managing director Christian Beckmann. Today, the project has grown thanks to another energy supplier and new investments. It provides heat to up to 28,000 households in several districts across Hamburg. It saves up to 120,000 tonnes of CO2 per year. Using waste to produce energy, Hamburg is showcasing how the industry can heat up a city without heating up the climate.
Euronews
21-07-2025
- Business
- Euronews
Hamburg's industrial waste heat project: a model for climate-neutral district heating?
Just a few kilometres from Hamburg's centre, the multi-metal company Aurubis produces more than 400,000 tonnes of copper every year. During the refining process, sulphur in the copper concentrates reacts with oxygen to form sulphuric acid, a valuable subproduct. This chemical reaction also releases large amounts of heat, which is now transferred to water and delivered through the city's district heating network. From wasted heat to warming homes Before this system was implemented, this thermal energy had no use. 'We took water from the river Elbe and cooled down the heat that came from the process. It wasn't used for anything. It was just wasted', explains Dr Holger Klaassen, director of corporate energy and climate affairs at Aurubis. That all changed when the energy supplier Enercity Contracting partnered with Aurubis with the idea of channelling the heat to the district heating system of Hafencity East, a growing residential area that was once part of the city's port. Both companies invested more than €20 million to bring the project to life. 'We needed a total retrofit of the contact plant where the sulphuric acid is produced. We needed a big heat exchanger, pumps, pipes, very special steel and stones that are able to absorb the heat combined with the acid', Dr Klaassen says. Enercity Contracting built an energy station to store and pump hot water, along with a gas-fired boiler to back up the system during copper production downtimes. A 3.7-kilometre pipeline now links the Aurubis facility directly to the city. A replicable model for greener cities Hamburg's industrial waste heat project is unique in part due to the copper smelter's close proximity to the city and the availability of CO₂-free waste heat. Still, Dr Klaassen believes the model could be replicated in other cities. 'What would help to make it more economically feasible would be incentivising the production or use of CO2-free heat by, for example, providing free allocations in the European emission trading system or developing some kind of green markets', he concludes.
