From sewage treatment to power generation: Hybrid power plant on the Emscher River

At the Emschergenossenschaft water management association’s sewage treatment plant site, as much as 70 to 80 per cent of the plant’s energy requirement is already self-generated today. Now, through the project titled “Vom Klärwerk zum Kraftwerk” (“From sewage treatment to power generation”), the operators are going a step further. With the help of an innovative concept, the sewage treatment plant is set to become fully energy self-sufficient in the future.

With a capacity at a population equivalent of 1.34 million, Bottrop sewage treatment plant is one of the largest sewage treatment plants in Germany and has set itself an appropriately major goal: Of the approx. 32 million kilowatt-hours of electrical energy required for its operation per year, 100 per cent will be self-generated on-site at the sewage treatment plant in the future.

Engine for progress:

  • energy self-sufficient sewage treatment plant
  • reducing CO2 emissions by 70,000 tonnes per year
  • five renewable energy sources being used in one place

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Night image of the sewage treatment plant in Bottrop.

The goal: an energy self-sufficient sewage treatment plant

Sewage treatment plants are among the main consumers of energy in urban areas. The sewage treatment plant on the Emscher River in Bottrop therefore set itself the ambitious goal to minimise its use of electricity from the main grid. In the future, Emschergenossenschaft wants to meet its energy requirements entirely through individual, decentralised renewable energy systems.

Five renewable energy sources in one place

To date, the Bottrop sewage treatment plant has managed to meet between 70 and 80 per cent of its energy demand by means of a sewage gas CHP unit and a sludge incineration system. In order to increase this rate to 100 per cent, the Emschergenossenschaft association came up with an innovative concept. Using a modular structure, the following are being installed: a wind turbine, four new CHP modules, a photovoltaic system, a hydrodynamic screw as part of the sewage treatment plant and a new steam turbine as part of the existing sludge incineration. The wind turbine, the PV modules and a sewage gas CHP are already operational.

A thermo-solar sludge drying facility will also be built, making the addition of coal for sludge conditioning unnecessary. In total, the sewage treatment plant is reducing CO2 emissions by 70.000 tonnes per year thanks to the clever system on which it is based. With the simple, modular structure of its individual energy systems, the project can serve as a blueprint for other sewage treatment plants in Germany.


Construction of the windmill


Partners and sponsors

  • Emschergenossenschaft
  • Landesregierung NRW
  • Ministerium für Wirtschaft, Energie, Industrie, Mittelstand und Handwerk (MWEIMH)
Counselling centers:
  • EnergieAgentur.NRW