Schweinfurt sewage treatment plant, Bavaria (DE) 

Double Use of Infrastructure: Foldable Solar Roof Above the Aeration Basins in Schweinfurt

The municipal wastewater utility of Schweinfurt is taking new steps in sustainable energy production. Since 2024, a foldable solar roof of the third generation has spanned the aeration basins of the treatment plant – producing electricity right where it is needed while making double use of existing infrastructure.

Back in 2022, the decision was made to examine the installation of a solar roof above the basins. The aim: significantly increase the plant’s self-supply of electricity and reduce energy-related emissions. After about two years of planning and construction, the innovative system was commissioned in August 2024, with final acceptance on October 7, 2024.

The installation consists of 18 folding roof tracks with a total of 864 solar modules and an installed capacity of around 372 kWp. The expected annual output is about 336 MWh – a significant contribution to the plant’s energy self-sufficiency.

Technology is designed not only for performance but also for operational safety. In case of storms, hail, or snowfall, the roof automatically retracts into a protected position. A weather-adaptive control system and an uninterruptible power supply ensure safe operation even during grid outages.

Another key advantage: no additional land is required. Around 2,325 square meters above the aeration basins are used twice, while accessibility and operations remain fully ensured.

With this project, Schweinfurt’s wastewater utility sets a visible example of innovation and sustainability. The foldable solar roof demonstrates how treatment plants can make a substantial contribution to the energy transition – efficiently, safely, and with future-oriented technology.

Project Facts Schweinfurt

  • Location: Municipal wastewater utility Schweinfurt, Schulgasse 13, DE-97424 Schweinfurt

  • System: Foldable solar roof, generation 3

  • Installed capacity: 371.5 kWp

  • Modules: 864 units

  • Roof tracks: 18 (2 × 9 tracks of 48 modules each)

  • Inverters: 3 units

  • Expected annual yield: ~336 MWh

  • Double-used area: ~2,325 m² (above aeration basins)

  • Commissioning: August 2024

  • Final acceptance: October 7, 2024

  • Owner/Operator: Municipal wastewater utility Schweinfurt (Operations management: Nadine Scheyer)