Bifacial Rooftop Vertical Solar Panels Shine In Norway

---

Support CleanTechnica's work through a Substack subscription or on Stripe.

---

Tromsø is a city in Norway that is located north of the Arctic Circle. Most might think that makes it a poor choice for solar power, but, in fact, the roof of Tromsøterminalen, a cold storage facility located at the city’s port facility, now has the world’s largest installation of vertically mounted bifacial solar panels.

The installation was completed by Oslo based Over Easy Solar, which says in a blog post announcing the completion of the project, “Traditional solar panels are usually installed at an angle, but vertical solar opens new opportunities — especially in northern latitudes. By mounting panels vertically, rooftops can:

• Capture more energy from low-angle sunlight, which is common in the north.
• Generate more electricity in the morning and afternoon, when demand is highest and electricity prices are typically more expensive.
• Stay clear of snow accumulation, improving year-round performance.
• Remain easy to access and maintain, with space to move between rows of panels.

CleanTechnica readers are a savvy lot when it comes to clean energy in general and solar power in particular. Many of you will have questions about how solar can be effective at high latitudes. Over Easy has some answers. It says: “Northern climates present a unique set of challenges for a flat roof solar installation. The risks are not well understood because these are relatively young markets and there are many inexperienced providers of solar solutions in these areas. Most solar panels and mounting systems have been developed with very different climatic conditions in mind, and the installations will experience:

• High wind exposure
• High snow accumulation
• Low sun angles

“All these factors can reduce performance and increase the risk of damage to the solar installation or even the building itself. Conventional flat roof PV systems — often tilted solar panels in ballasted mounting systems – are developed for more southern climates, and not designed with these conditions in mind.

“Vertical photovoltaics (VPV) is the future of flat roof solar in extreme weather regions. The VPV Unit is developed in Norway with the challenges of northern Europe’s climate in mind, and performs exceptionally well in wind-exposed, snowy environments where standard solutions often fall short.”

Wind is of particular concern in an area of the world where winter storms are common. The company says: “A solar installation on a flat rooftop is particularly vulnerable to wind uplift — the vertical force that can lift conventional solar panels off the roof. To function safely in windy areas, traditional systems rely on heavy ballast or complicated mechanical fastenings, which add load and increase the risk of roof damage like insulation compression or membrane leakage.

“The VPV unit has a fundamentally different approach. Because vertical panels generate no uplift, they typically don’t require ballast or roof penetrations – simplifying installation and preserving roof integrity. The key lies in our aerodynamic design:

• Low-profile panels (~25 cm) that reduce wind exposure
• Arrays that distribute wind loads across the system
• Close panel spacing that shields each module from wind

“This makes the VPV Unit a reliable, ballast-free solution for most flat roofs, including those in coastal or open terrains.”

Vertical Solar For Snowy Conditions

Conventional solar systems on flat roofs are easily covered by snow. Even a few centimeters of accumulation can halt energy production completely. In extremely snowy areas, the weight of the snow can damage the solar panels or the membrane and roof below.

Vertical solar panels work differently, Over Easy says, because they remain partially or fully above the snow. In fact, sunlight reflected off the snow increases bifacial performance, and the vertical panels provide a passive melting function. The vertical array therefore does not add any snow load to the roof of a building or concentrate the load on the roofing membrane or insulation.

In a study by the University of Tromsø of two solar PV systems at 69°N, the vertically mounted bi-facial HJT system from Over Easy Solar achieved substantially higher specific yield than a conventional monofacial system tilted at 10 degrees. The vertical system remained free of snow and benefited from reflected sunlight, while the conventional system remained snow covered and inactive for extended periods.

“Since vertical installation angle is not optimal for solar panels, many believe that vertical solar panels always under-perform. But, bi-facial solar panels that produce from both sides give very good energy yield. In fact, in northern latitudes, we’ve seen that vertical bi-facial panels can greatly exceed the performance of traditional systems,” Over Easy says. “At the installation in Tromsø, we have seen 40 to 50 percent higher specific energy yield (kWh/kWp) for vertical solar than for a reference installation using a conventional 10° tilt east-west flat roof solar solution.”

The solar panel installation in Tromsø has shown that the vertical orientation provides a:

• Better angle of incidence for the sunlight coming from low angles gives higher efficiency

• East-west vertical orientation captures energy from almost all angles very well in northern areas
• Higher value energy produced during morning/evening hours and early spring, aligning better with demand

“If you’re planning solar for a flat roof in a northern or alpine region, conventional solutions may not be optimal. With minimal structural demands, no need for ballast in most cases, and real world validation from across Norway and Europe, we see that vertical solar is a future-proof solution for buildings that face tough weather, wind, snow and northern conditions.”

The system consists of 1,600 vertical photovoltaic units with a total capacity of 320 kilowatt peak (kWp) power. “It’s fantastic to see such a large solar installation in Tromsø,” said Trygve Mongstad, CEO of Over Easy Solar. “As far as I know, this is the world’s largest vertical rooftop installation.”

The project was completed in partnership with engineering company ENØK Total. Over Easy Solar emphasized that vertical solar is more than just a technical tweak and called it a scalable solution for transforming unused flat rooftop space into reliable, low-maintenance power sources.

It added that VPV systems are a viable solution for rooftop solar, especially in urban areas where the demand for clean energy is growing but there is limited space available for installing solar systems. This installation may pave the way for broader adoption of the technology across the world, particularly in climates once considered inhospitable for solar energy.

“The short installation time was also an important factor,” Arne Christian Bredesen, ENØK Total technical project manager, noted in a press release. “We are very satisfied with the system, and confident that this is the right system for the building.”

Recently, CleanTechnica readers have been discussing whether solar works well enough in northern US states or Canada to be worthwhile. The answer seems to be — much like electric vehicles — there are many solutions, depending on what the needs are. Near the Equator, floating solar panels that point upward toward the sun may be best. Above the Arctic Circle, vertical panels may be the answer.

Vertical solar is also finding acceptance in agricultural settings where solar panels and crops can go hand in hand. The takeaway seems to be that solar is the answer. All we have to do is figure out the best way to maximize its benefits for any particular use case.