EEW boosts Hannover district heating capacity

Key Takeaways

• EEW is upgrading its Hannover-Lahe WtE plant to raise district heating capacity from 50 to 85 MW – with no additional waste input.
• A new steam turbine bypass enables flexible operation: full heat priority in winter, CHP mode at lower demand.
• Work began during the current maintenance revision; full capacity available for the 2027/28 heating season.
• The project supports Hannover’s coal exit, replacing heat from the shut-down Stöcken coal unit.
• Enercity will use the plant flexibly within its portfolio, balancing heat and electricity output to meet demand.

Plant operator EEW is upgrading its Waste-to-Energy plant in Hannover-Lahe to increase the usable heat output for Enercity’s district heating network. The optimisation raises the maximum heat capacity from 50 to up to 85 megawatts. This happens without processing additional waste volumes.

The first measures are being implemented during the plant’s current scheduled maintenance revision. All conversion work is due to be completed by the second quarter of 2027. As a result, the full additional heating capacity will be available for the 2027/2028 heating season. In parallel, Enercity is investing in pipeline expansion to distribute the increased output across Hannover.

From coal to waste heat

The project supports Hannover’s transition away from coal-fired power. Following the shutdown of unit 1 at the Stöcken coal plant, Enercity is broadening its heat generation portfolio with the aim of exiting coal entirely. Waste-derived heat from Hannover-Lahe is a key component of that strategy. In early 2025, Enercity and EEW agreed to jointly develop the existing plant’s potential for long-term heat and electricity generation in Hannover.

Turbine bypass enables flexible operation

The capacity increase is achieved through a new steam turbine bypass. At times of high heating demand – particularly in winter – EEW can route steam directly to district heating, bypassing the turbine entirely. When heating demand is lower, the plant continues to operate in combined heat and power (CHP) mode with partial electricity generation.

“With the energy optimisation, we are creating the technical conditions to provide significantly more district heating from the same volume of waste. For this, we bypass the turbine in certain operating situations: when there is very high demand for district heating, especially in winter, we can fully divert the steam to district heating. In other modes, operation in combined heat and power with partial electricity generation remains possible. This reduces heat dissipation to the environment and increases the plant’s efficiency. The trade-off is lower electricity production at higher heat output – but overall, we gain significantly more usable energy for Hannover,” said Malte Bieber, technical project manager for energy optimisation at the EEW Hannover site.

Flexible asset in a mixed portfolio

Enercity, parent company of EEW’s competitor Danpower, plans to use the optimised plant as a flexible component within its broader power and heat generation portfolio. Depending on demand and market conditions, the company can choose to prioritise heat or electricity output. At cold temperatures, the higher heat capacity contributes to security of supply. Alternatively, at lower heating demand, the plant can continue to generate electricity.

“The expansion of heat extraction from waste recovery is an important step towards green district heating. Using existing waste heat sources makes sense for the energy transition, as it makes better use of existing infrastructure and heat potential. The good collaboration on this project also makes it possible to feed more waste heat into the city network as early as next year, or to generate electricity efficiently through intelligent use of combined heat and power,” said Conrad Zimmermann, asset manager for thermal generation and district heating at Enercity.

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