en.Wedoany.com Reported - German energy supplier Enercity is constructing a 50-megawatt power-to-heat plant as part of its coal phase-out strategy and efforts to decarbonize district heating production, while also aiming to relieve grid pressure by absorbing surplus renewable electricity.

The steady growth of installed wind and solar photovoltaic capacity has led to periods of very low or even negative electricity prices and placed increasing strain on the grid. Enercity is expanding its ability to absorb such electricity surpluses and use them for heating.

In the Herrenhausen district northwest of Hanover, Lower Saxony, within the historic Herrenhausen power plant, Enercity has been operating a 20 MW electrode boiler since 2020, with its capacity set to increase to 26 MW. Once the new 50 MW facility is completed, it will significantly boost the utility's power-to-heat capacity.

These boilers can supply heat directly to Hanover's district heating network or charge existing thermal storage systems. The flexibility offered by this technology is particularly important when large amounts of renewable energy are available on the grid or when heat demand is very high, such as on especially cold winter days.

These systems also help ensure secure supply to the district heating network, as they can be brought into operation within a short time during periods of high demand. Enercity states that power-to-heat is not designed for continuous operation, but specifically for situations where the energy system needs support.

The existing Herrenhausen facility is used to rapidly heat water in the district heating storage tank from 98°C to a winter supply temperature of up to 120°C. This allows stored heat to be used during peak demand periods, reducing the need to operate other generation assets and supporting more economical district heating production.

As part of its strategy to decarbonize district heating in Hanover, Enercity plans to completely replace its second coal-fired unit by the end of 2027. The company expects that a "very large share" of district heating production will be climate-neutral by then, using technologies including power-to-heat, large heat pumps that extract ambient heat from river and wastewater treatment plant water, and expanded waste heat recovery.

Enercity also plans to build another power-to-heat facility with a capacity of 100 MW in the Rodenbruch district near Hanover.