Symbolic start of industrial heat feed-in to Hamburg city network 

Today Aurubis AG CEO Dr. Toralf Haag and Hamburger Energiewerke GmBH (HEnW) Managing Director Michael Prinz joined First Mayor of the Free and Hanseatic City of Hamburg Dr. Peter Tschentscher in inaugurating the HEnW thermal storage system, symbolically kicking off the supply of carbon-neutral industrial heat. The two companies have worked together to lay the groundwork for providing up to 20,000 Hamburg households with carbon-neutral heat and avoiding up to 100,000 t of CO2 emissions in the future. This represents the on-schedule fulfillment of the contract the companies signed in December 2021. Both its size and complexity make the project unique in Germany.

In 2024, multimetal producer Aurubis again significantly invested in a method for extracting the surplus heat generated during a copper production sub-process at its Hamburg plant. This heat is fed as hot water into the pressure heat accumulator in Hamburg Veddel recently completed by Hamburger Energiewerke. The accumulator already holds up to four million liters of hot water from Aurubis heat today. It works a bit like a thermos, and the heat is released into Hamburger Energiewerke’s over 860-kilometer-long city network when needed. The project received funding from the German Ministry for Economic Affairs and Climate Action (BMWK) and the Hamburg Investment and Development Bank (IFB). In combination with the heat accumulator, the industrial waste heat supplied by Aurubis is a building block in the Tiefstack energy park, Hamburger Energiewerke’s plan to phase out coal in Hamburg by 2030. Aurubis and Hamburger Energiewerke are actively shaping the heat transition with the current project and making an important contribution to meeting Hamburg’s climate targets. The heat supply is scheduled to come online in the 2024/25 heating period.

First Mayor of Hamburg Peter Tschentscher:  “Using innovative technology is the best way to protect the climate. This includes leveraging industrial surplus heat to keep homes warm. In the future, Aurubis will feed the process heat generated during copper production into the Hamburger Energiewerke district heating system. Reusing this waste heat from the copper smelter drives decarbonization in the buildings sector by preventing up to 100,000 t of CO2 emissions every year. Projects like this allow us to take giant strides forward on our path to a carbon-neutral Hamburg. We are linking industry and climate protection, strengthening our competitiveness as an industry hub and realizing our climate plan, which includes ambitious CO2 targets for the city of Hamburg.”

Christian Maaß, Director General Heat, Hydrogen and Efficiency, Federal Ministry for Economic Affairs and Climate Action: “There is huge potential in waste heat reuse, and the federal government’s goal is to make it easier to realize projects like this in the future by further improving the political parameters. An enormous amount of surplus heat from artificial intelligence data centers and electrolyzers for producing hydrogen will enter the market in the coming years. This surplus heat should be harnessed to generate inexpensive district heating instead of being discharged into the atmosphere. The Hamburg project is an excellent example, and the government is completely behind it.”

Jens Kerstan, Senator for the Environment, Climate, Energy and Agriculture: “Everyone linked to the Hamburg city grid will benefit from the HEnW heat accumulator: Aurubis, Hamburger Energiewerke, the environment, and especially the people of our city. We are closing a loop and enabling the direct use of energy in Hamburg households that has otherwise gone to waste. I am particularly pleased that all the surplus heat at Aurubis is now part of the heat supply. The first two segments have been in operation for several years, and we had the foresight to create the infrastructure for the additional feed-in from the third segment back then. This national flagship project is setting standards and is another success story for the heat transition in Hamburg.

Aurubis AG CEO Dr. Toralf Haag: “With its metals, Aurubis is laying the foundation for the energy transition. The Industrial Heat project clearly shows that sustainable business activities and actions go hand in hand here, and that as an industry, we are an important part of the solution for the challenges of our time. Together with our partners, we have developed an innovative solution for an environmentally friendly heat supply. If we want to see more forward-looking projects like this, we need more regulatory recognition of green industrial heat, which should be fully recognized in emissions trading, and an efficient market for green proofs of origin.”

Hamburger Energiewerke GmbH Managing Director Michael Prinz: “Waste heat from Aurubis gets us another step closer to phasing out coal in Hamburg. It encompasses the huge surplus heat potential at the Hamburg site that we will be extracting for our new energy park and the climate-neutral district heating system of the future. Together with Aurubis, we are setting a new benchmark for the heat transition in Germany with the feed-in of industrial heat on this scale.”

The origin of heat at Aurubis

The heat is generated in Aurubis’ contact acid plant in Hamburg where sulfuric acid, a by-product of copper refining, is formed in multiple process steps. This process is an exothermic chemical reaction that generates CO2-free heat at a temperature suitable for carbon-neutral district heating. The technology has been successfully used at the Aurubis plant since 2018 to supply heat to enercity to cover HafenCity East and Rothenburgsort, and is now being significantly expanded. The Industrial Heat project highlights the multimetal company’s ambitious decarbonization targets and underscores Aurubis’ efforts to pioneer solutions for ecological and sustainable business activity.

Integrating industrial heat into the HEnW district heating network

Heat production at Aurubis and the heating needs of district heat customers often occur at different times. So the extracted industrial heat is temporarily stored as 105 degree Celsius water in the nearby Hamburger Energiewerke pressure heat accumulator. The heat can then be fed into the over 860-kilometer city network using a network pump system. To deliver the industrial heat to Hamburg households, Hamburger Energiewerke is using an existing enercity Contracting Nord GmbH pipeline to cover the first segment from the Aurubis plant to the Elbe River crossing. Starting at Billhorner Brueckenstrasse, a 2.8-kilometer HEnW district heating pipeline continues to the heat conversion plant at Spaldingstrasse. The heat conversion plant serves as an interface for integrating various heat sources into the district heating network. The final steps for integrating the industrial heat supply into the city network will be carried out before the actual launch.

In addition to industrial heat and waste heat from the Borsigstrasse waste recycling plant (MVB), river water heat pumps and another heat storage tank are used to reliably generate climate-friendly heat for the city. 

Additional funding information

A number of Aurubis and Hamburger Energiewerke projects make up the Industrial Heat or District Heating project. At Aurubis, three independent projects extract heat from three different production units in the contact acid plant. For these three projects, Aurubis applied for funding from BAFA as part of the “Federal Funding for Energy and Resource Efficiency” scheme, Module 4: Energy and resource-related optimization of systems and processes. Hamburger Energiewerke received funding from BAFA as part of the Model Project Heat Network Systems 4.0 (Module II) program. The Hamburg Investment and Development Bank (IFB Hamburg) also provided funding for the HEnW project in keeping with the “Companies for Resource Conservation” funding guidelines.

Facts and figures 

HEnW pressure heat accumulator on Georgswerder Damm, Hamburg-Veddel 

• Size: 35 meters high, 14 meters in diameter 
• Volume: four million liters 
• Water temperature: 105 degrees Celsius 
• Weight of domed roof: 72 tons 

Aurubis heat extraction 

• Two intermediate absorbers installed, each weighing 250 tons — this is where heat is generated when sulfuric acid, a copper refining by-product, is produced 
• Special heat exchangers installed 
• Length of heat pipes on the plant premises: around one kilometer 

Performance

• Carbon-neutral heat for up to 20,000 households 
• Up to 100,000 t of CO2 emissions avoided  

More information, videos and photos are available at our digital Press kit.