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Solar panels aren’t just built on roofs. With a special technology, it also works on sewage treatment plants.
Solar systems are not welcome everywhere. They require space, could interfere with the landscape or monument protection does not always allow them. So why not install solar panels on highways, over parking lots or orchards? This is already being practiced to some extent. Such systems are also increasingly being built over sewage treatment plants. But these have to be movable, as an inspection in Grenchen (SO) shows.
Legend:
The macaw in Grenchen. The largest extendable solar system in Switzerland is scheduled to go into operation here in a few weeks.
SRF/Christoph Studer
The sewage treatment plant in Grenchen is located between the A5 motorway and the regional airport. 17 communities from the cantons of Solothurn and Bern are connected to the system.
The Grenchen wastewater treatment plant (Ara) is currently having a solar roof installed over the treatment tank. Panels will be installed on 7,400 square meters. In the future, the sewage treatment plant will use around 70 percent of the solar energy produced itself, primarily for the ventilation of the treatment tanks, which must run around the clock. The final cabling is currently being installed – the system is expected to produce electricity from April.
Legend:
This is what a closed solar system from the same company in Glarnerland looks like. There is also wastewater underneath.
zvg/dhp technology
The association of municipalities invested a total of around three million francs in the solar system – it only took around a year from the start of the project planning to commissioning. The macaw needs most of the electricity it produces itself.
Largest foldable system
The Grenchen solar system above the wastewater is the largest of its kind in Switzerland. The solar panels can be extended when the weather is nice. If there is a threat of thunderstorms, hailstorms or snowfall, the system can be retracted.
Solar panels not just on roofs, but…
Even if maintenance work is necessary on the clarification tanks, the panels would get in the way, explains Benno Schläfli, managing director of Ara Grenchen: “We have to maintain the system regularly and be able to take out pumps, for example. It would be inconvenient if you had to dismantle the permanently installed solar panels.”
The foldable solar system is more expensive than conventional, fixed photovoltaic systems. Nevertheless, Ara managing director Benno Schläfli believes the purchase is worth it: “It’s worth it, it makes sense.”
They expected a good 20 years in which the system would be amortized. Schläfli is convinced that this will happen more quickly with the current high energy prices.
Even at motorway service stations?
The manufacturing company based in the canton of Graubünden plans to install foldable solar panels over the wastewater at additional locations. In Reinach (AG), in Glarnerland and in Davos (GR), for example, she has already built similar buildings. She is also active in Germany.
The panels have a future not only in wastewater treatment plants, but also in motorway service areas, explains the company DHP Technology to SRF. The electricity produced can be used to charge electric cars and operate the rest stop.