Hamburg, in northern Germany, is home to a one-of-a-kind district heating system. The hot water that supplies it is largely obtained from waste heat from the city’s copper smelter, meaning no CO2 is released.
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.
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.
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 an additional partnership with the supplier Hamburger Energiewerke.
Overall, Aurubis and both partners manage to supply up to 28,000 households with industrial heat in several districts across Hamburg.
This 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.