A Norwegian pilot project is demonstrating how vertical solar modules can help schools and other public buildings meet both green roof and solar installation requirements during modernisation, which is posing a challenge for cities across Europe amid tightening regulations and increased renovation funding.
Driving this innovation is Over Easy Solar’s prefabricated vertical photovoltaic (VPV) system, which can be installed on flat or green roofs without disturbing the underlying vegetation. The bifacial modules harvest sunlight from both sides and require no roof penetration. At just 12 kilograms per square metre, the units are lightweight and can be installed up to ten times faster than traditional rooftop systems – around 15 minutes per kWp.
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Performance and pilot results
“In the 2022 pilot project, we achieved high electricity yields and found that the green roof beneath the modules was actually in better condition than the open areas,” said Andreas A. Nilsen of Oslobygg KF, Oslo’s public building authority. “The system reduces maintenance costs while delivering clean energy.”
At Løren School, Oslo, 46 kWp of vertical PV was installed on a 500-square-metre green roof in 2022, retrofitted to a building constructed in 2017. Since then, Over Easy Solar has brought the technology to 13 countries, with a particular focus on public buildings and educational institutions. Other major installations include 248 kWp of solar capacity on the green roof of Ullevål Stadium in 2024 and 320 kWp at Tromsøterminal.
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Market potential and collaborative solutions
Across Europe, cities are facing similar regulatory pressures. In Germany alone, billions are earmarked for school modernisation, and the EU Buildings Directive will soon require solar on public buildings, while many cities are also enforcing strict green roof mandates. According to the German Green Roof Association, nearly 90 percent of larger cities have integrated green roofing into their development plans.
“The Løren School project shows how even older school buildings can meet both regulatory requirements through innovative roof concepts,” said Trygve Mongstad, CEO of Over Easy Solar. “Given the current investment in German schools, we see significant potential for this solution.” Other countries, including France, Switzerland, Austria, and Belgium, have also introduced green roof requirements or incentives for public buildings.
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Expanding partnerships
Over Easy Solar is now working with green roof specialist Sempergreen to offer integrated systems across Europe, targeting both new builds and retrofits. The company points to the modular design and rapid installation as key advantages for project developers and school authorities seeking to navigate overlapping mandates.
Norway’s role as a solar innovation hub is growing. Recent advances include floating PV installations and high-efficiency silicon production, supporting the country’s goal of reaching 8 TWh of solar generation by 2030. (TF)
