EWE modernizes boiler house with heat pumps and CHP unit

02.07.2025

Source: E & M powernews

The system technology in the boiler house of the utility company EWE in Erkner, Brandenburg, is complete - the second heat pump has been delivered. Green district heating is to be supplied from the fall.

A combined heat and power plant and heat pump combination is to help ensure the district heating supply in a boiler house in the small town of Erkner (Oder-Spree district in Brandenburg) from the fall. With the second heat pump, the boiler house's system technology is now complete, the operating company EWE AG announced on July 1. "As soon as the heat pumps are ready for operation, we will start generating green district heating right here in the boiler house in Erkner Mitte," explains Andreas Saadhoff, Managing Director of the EWE subsidiary "TEWE".

Until now, the EWE subsidiary "TEWE" has operated three natural gas-fired combined heat and power plants and a three-part district heating network in Erkner. This has been partially modernized and converted in recent months.

The conversion of the first boiler house will increase the proportion of renewable energies in the connected heating network from zero to more than 50 percent. This is partly due to the biomethane fuel for the CHP unit and partly due to the recently completed installation of heat pumps. Until now, the heat at Heizhaus Mitte was generated exclusively with natural gas boilers - in future, a system of heat pumps and biomethane CHP will take over the supply. The largest customers include the town of Erkner itself, an educational center and the municipal housing company Erkner (WGE), the largest landlord in the town of 12,000 inhabitants.

The two other energy centers in Erkner, which are also operated by TEWE and currently still work with natural gas boilers, are also to be gradually converted in the interests of a climate-friendly heat supply. Concrete plans and technical concepts are currently being drawn up.

Only economical with subsidies

The new generation system in Erkner consists of a biomethane cogeneration plant (CHP) for base load supply and a two-part heat pump system. The CHP unit was delivered last fall and will generate electricity and heat simultaneously from biomethane with an electrical output of 360 kW and a heat output of 400 kW (we reported). The green electricity generated will in turn power the 530-kilowatt heat pump system. According to EWE, the local sector coupling is designed in such a way that there is no additional load on the electricity grid.

The heat pump technology combines an air-to-water and a water-to-water heat pump. The air-to-water heat pump was already there, the other has now been delivered. According to EWE, together they enable the heating water to be gradually heated up to 80 degrees Celsius - supplied from environmental heat and supported by a heat storage tank. Both heat pumps are operated with natural refrigerant.

The project in Erkner Mitte is supported by funds from the Federal Fund for Efficient Heating Networks (BEW). TEWE is investing 2.4 million euros in the conversion of the heat supply system, 600,000 euros of which will come from subsidies. As a TEWE shareholder, EWE is responsible for planning and construction supervision. As the companies emphasize, such projects require subsidies: "Without state funding, a resource-saving district heating supply cannot yet be built and operated economically. Thanks to state support from the federal subsidy for efficient heating networks, we can now realize our plans," said TEWE Managing Director Saadhoff.

Author: Heidi Roider