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Hamburg – Energy provider Enercity is set to manage the heat supply for the new Grasbrook district in Hamburg. By 2031, more than 90 percent of the heat is projected to originate from renewable energy sources and unavoidable waste heat. A central cooling supply is also planned to commence in 2035.
The Current State of Renewable Energy in Germany
While renewable energies covered over half of Germany’s electricity consumption in 2025, their share in heat and cooling consumption was only 19 percent. District heating continues to be predominantly generated using fossil fuels. To decarbonize district heating, providers must tap into additional renewable heat sources and industrial waste heat, integrating them into existing or new heating networks.
Enercity Expands Heating Network with Aurubis Waste Heat
Hafencity Hamburg GmbH awarded the service concession to Enercity Contracting Nord GmbH following a Europe-wide tender. Enercity already operates a heating network for the eastern Hafencity, Rothenburgsort, and parts of Peute. A significant heat source is industrial waste heat from the Hamburg plant of copper producer Aurubis. By connecting to the existing network, Grasbrook will also be able to utilize this industrial waste heat. According to Enercity, 85 percent of the heat in the existing network already comes from renewable energies and industrial waste heat.
The expansion plan includes approximately 7.3 kilometers of additional heating pipelines and further generation facilities. Heat pumps are intended to utilize ambient heat from the air and, if applicable, wastewater, while biomethane will cover peak demands. Enercity aims for a 100 percent share of renewable energies and unavoidable waste heat by 2040.
Heat Supply by 2031, Central Cooling by 2035
The Grasbrook district, spanning approximately 47 hectares of former industrial and logistics land, is expected to accommodate at least 3,000 homes and around 16,000 workplaces. Initial construction projects in the Moldauhafenquartier are scheduled to begin in autumn 2028, with heat supply commencing there in 2031. Public participation for the Moldauhafenquartier’s development plan ran from July to September 2026. In the Hafentorquartier, which is also part of Grasbrook and more commercially oriented, a grid-connected cooling supply with approximately 1.8 kilometers of pipelines is planned from 2035. Centralized systems can reduce the need for building-specific technical spaces. In the neighboring Hafencity, Enercity already uses industrial waste heat to cool the Previer prevention center via an absorption chiller.
District Heating: Natural Gas Remains Key Energy Source Nationwide
According to the BDEW, the share of renewable energies and unavoidable waste heat in German district heating generation was 34.4 percent in 2025, a slight decrease from 35.0 percent in the previous year. Natural gas remained the most important energy source at 49.3 percent. Together with hard coal, lignite, and mineral oil, fossil fuels still accounted for over 60 percent of district heating generation. To reduce fossil fuel consumption, additional heat sources must be developed. Besides industrial waste heat, as planned for Grasbrook, large heat pumps, geothermal energy, and solar thermal energy are viable options. The economic feasibility of these sources depends on local conditions and existing network infrastructure.
Industrial Waste Heat: Distance and Temperature are Crucial
Industrial waste heat can play a vital role in the transition of district heating. However, its utilization requires suitable distances between heat sources and consumers, adequate temperatures, and economically viable investments. Additionally, different load profiles need to be considered: industrial plants sometimes provide continuous heat, while heating demand fluctuates seasonally. Heat storage and supplementary generation plants can balance these differences. Existing networks facilitate additional connections, provided their capacities are sufficient.
Heat Planning Act Sets Increasing Minimum Shares
The Heat Planning Act sets a nationwide target of an average of 50 percent renewable energies and unavoidable waste heat in heating networks by 2030. For existing networks, a minimum of 30 percent is generally mandatory from 2030 and 80 percent from 2040. New heating networks must achieve 65 percent from March 2025. Complete conversion is mandated by the end of 2044.
With the planned share of over 90 percent renewable energies and unavoidable waste heat for Grasbrook, Enercity is pursuing a supply target that significantly exceeds the federal legal minimum requirements for heating networks. The project also demonstrates that the conversion of district heating does not solely depend on the construction of new generation plants. The expansion of existing heating networks and the utilization of already available industrial waste heat can also contribute significantly.
Source: https://www.solarbranche.de/news/nachrichten/artikel-40120-wrmewende-in-hamburg-neuer-stadtteil-grasbrook-soll-ab-2031-ber-90-prozent-erneuerbare-wrme-und-abwrme-nutzen
