A Hybrid Sewage Power Plant
One of Germany’s largest sewage treatment plants is aiming to become 100% energy self-sufficient through a range of decentralized renewable energy systems.
Bottrop sewage treatment plant serves a population of 1.34 million and currently self-generates 70–80% of its energy requirement. Through the project ‘Vom Klärwerk zum Kraftwerk’ (‘From sewage treatment to power generation’), the plant’s operators are aiming to self-generate 100% of the plant’s total demand on-site (32 million kilowatt-hours of electrical energy per year). This will be met through individual, decentralized renewable energy systems.
Individual, decentralized renewable energy systems
To date, the Bottrop sewage treatment plant generates 70–80% of its energy demand from a sewage gas CHP unit and a sludge incineration system. To increase this rate to 100%, the plant will install:
- A wind turbine (3.1 megawatts of power)
- Four new CHP modules (each with a capacity of around 1.2 megawatts)
- A solar photovoltaic system on a roof surface
- A hydrodynamic screw as part of the sewage treatment plant (around 80 kilowatts of power)
- A new steam turbine as part of the existing sludge incineration
- A thermo-sludge drying facility, which uses the sun’s energy to extract the water from the excessively liquid sewage sludge so that it can be burned more easily, making the use of coal for sludge conditioning unnecessary.
In total, the plant will reduce its carbon emissions by 70,000 tons per year, serving as a blueprint for other sewage treatment plants across the country and internationally.
Conclusion
Hybrid sewage power plants can use a variety of innovative decentralized renewable energy systems to become self-reliant and carbon-neutral.