The Hanover-based energy supplier Enercity is starting to implement the infrastructure work to connect a large heat pump to the electricity and district heating network in the Hanover-Leinhausen area. The plant is being built on the site of the municipal sewage treatment plant in the Herrenhausen district and will make an important contribution to the city's green heat supply from 2027 by utilising renewable energies with an output of 30 MW. Enercity is planning to invest around 56 million euros n the construction of the heat pump plant and infrastructure.
As part of the construction work, tunnelling for district heating pipes and the power supply for the heat pumps will take place under the Leine, which will extend over a length of around 4 kilometres. The river will be crossed at three points at a depth of around 10 metres in order to lay the pipelines.
The large heat pump will utilise the purified water from the sewage treatment plant as a heat source. The so-called clear water, which has a temperature of 12 to 16 °C, is channelled through heat pump modules that extract energy from it, causing the water temperature to drop before it is discharged back into the river. The discharged water is then heated to 95 °C to generate district heating.
Government funding for sustainable heating solutions
The project is being supported with 22.5 million euros as part of the federal subsidy for efficient heating networks.
„Enercity is investing around 1.5 billion euros in the expansion of green district heating by 2040. We are delighted that our investments in a sustainable and future-proof heat supply are being recognised. This will help us to finance further investments in climate neutrality“, said Prof. Dr. Marc Hansmann, Enercity's Chief Financial and Infrastructure Officer.
District heating is a central component of the city of Hanover's heating planning, which has set itself the goal of making the entire heating sector climate-neutral by the mid-2030s. In the long term, 14 sustainable heat sources are to feed the district heating network. In addition to sewage sludge and clear water, large heat pumps from rivers, biomethane cogeneration plants, a biomass cogeneration plant and geothermal energy will also be used.
In the long term, the district heating network is to be expanded from the current 360 kilometres to 550 km by 2040 in order to be able to supply around 18,000 buildings in Hanover (five times as many as today) with climate-friendly district heating.
