Vertical.Solar by Over Easy: Overcoming challenges for vertically mounted bifacial solar panels in different climatic conditions

Over Easy Solar: From Idea to Commercial Implementation Through the vertical.solar project, Over Easy Solar has transitioned from basic R&D and prototypes to product development aimed at commercialization of vertical solar panels for rooftops. This project has been pivotal in enabling the development of Over Easy Solar’s solution for prefabricated, vertical, bifacial solar panels for flat roofs. We have demonstrated that the concept works exceptionally well. We have achieved this by: - Building prototype installations from Tromsø in the north to Valencia in the south. - Developing a robust and advanced simulation model for performance calculations. - Demonstrating implementation of this model in a planning tool that simplifies project planning and sales. - Demonstrating that the system withstands strong winds without the need for anchoring or ballast. - Showcasing sustainability benefits over conventional systems through life cycle analyses. - Designing and improving the solar panels across two new generations. The prototype installations provided valuable data and insights that contributed to improved designs for more efficient transportation and installation. The prototypes also demonstrated that the system's installation is 10-15 times faster than traditional solutions, thanks to the prefabrication of the frame and panels. Performance (specific yield) ranged from 747 kWh/kWp in Tromsø to 1200 kWh/kWp in Valencia, with even greater potential in the next generation. In northern regions, east/west-oriented panels deliver superior results compared to conventional systems, while in the south of Europe the yield is below or similar to conventional systems. The reflection from the roof surface, known as albedo, plays a significant role. Tests conducted at our outdoor test facility with our research partner, the Institute for Energy Technology (IFE), showed that white roofing materials (albedo of 80-90%) increased performance by 20-25% compared to darker roofs. These data, combined with precise measurements of solar radiation and temperature, were used to validate our performance model. The model was developed by IFE using the PVlib algorithm library and has now been implemented in our VPV Planner tool. Wind load analyses conducted in collaboration with Fraunhofer ISE show that the system can withstand hurricane-strength winds without being anchored to the roof. This eliminates the risk of leaks and reduces installation time. Wind tunnel tests confirmed the stability of the design, thanks to the panels’ low height and strong friction with the roof surface. Long lifespan is crucial for sustainability and market acceptance. Climate chamber and outdoor tests conducted by IFE have ensured the selection of materials capable of withstanding 25-30 years of use. Life cycle analyses from Fraunhofer ISE show that our system has a global warming potential (GWP) of 63 kg CO2-eq/m², significantly better than conventional systems (127 kg CO2-eq/m²). Through this project, Over Easy Solar has also gained extensive media coverage and shared experiences through articles and blogs. Topics such as winter performance, albedo, and green roofs have engaged both experts and the general public. vertical.solar has provided us with a solid lead in the development of vertical, bifacial solar solutions. The results serve as a vital platform for our continued success. https://www.pv-magazine.com/2025/01/08/vertical-rooftop-pv-performs-better-than-conventional-rooftop-solar-under-the-snow/ https://www.pv-magazine.com/2023/05/29/cfd-tests-show-wind-resistance-in-vertical-rooftop-pv-systems/ https://www.forskning.no/de-regionale-forskningsfondene-energi-fornybar-energi/nye-solcellepaneler-produserer-mest-strom-pa-morgenen-og-kvelden/1990773

The vertical.solar project has enabled Over Easy Solar to develop the world’s first commercial product for vertical photovoltaics for rooftops, the VPV Unit, and support the marketing of it with science based results. Through the development of the prototype systems and performance analysis as well as other results, the development of the VPV Unit has been made efficient and targeted. We have been able to develop a solid marketing strategy to help us establish activity in Denmark, Germany, Netherlands, Austria, Switzerland, France, Spain and Greece. A key part of our marketing strategy is the inclusion of well-documented performance metrics, such as specific yield across different locations, stability during high winds (verified via wind tunnel testing and computational fluid dynamics), and thorough durability testing of components. The project has enabled this documentation. Environmental performance was also evaluated through a life cycle assessment (LCA), which showed the VPV system favorably compares to conventional PV systems. This is increasingly critical in PV marketing and will serve as a foundation for creating an Environmental Product Declaration (EPD) for the next generation of VPV products. The project has established a framework and roadmap for further development of Over Easy Solar’s products, manufacturing, and marketing. Key learnings will be further developed in the next projects and future products. This includes simulation models to streamline the planning of VPV systems, aligning with our goal to simplify the value chain from factory to rooftop energy production. For the research partners, the project has provided valuable insights. IFE gained expertise in developing and testing PV modules, enhancing Norway’s capabilities in this field and contributing to ongoing and future projects. Knowledge developed during vertical.solar is unique internationally, especially in the area of vertical bifacial PV. Fraunhofer ISE also advanced tools for evaluating wind loads on vertical panels, which will drive future innovations and research. The availability of the VPV Unit on the market is expected to expand the use of PV on flat-roof buildings, particularly on low load-bearing and green roofs, where PV installation was previously challenging. Its advantageous power production curve, delivering energy during high-demand periods in the morning and afternoon, adds value in today’s energy market. Verified ease of installation supports faster solar energy deployment, and we anticipate significant contributions to reducing CO2 emissions from electricity production. The vertical.solar project has been instrumental in positioning Over Easy Solar to make this impact.

About 50% of all solar cell capacity worldwide is installed on buildings. Yet, about 90% of roof areas on buildings are not utilized for any purpose, and, even in 2021, new buildings with excellent solar conditions are being built without solar installations. Over Easy Solar is developing a novel concept for a solar module with extremely efficient and simple installation for flat roofs. The solution has been made possible by recent development within bifacial solar cells. Patent-pending, the solution has been tested in a working prototype during summer 2021, where we demonstrated 10x faster mounting, good energy yields and a power production profile that will be of high value for future customers. The way Over Easy mounts the bifacial solar panels is unconventional; they are vertically aligned and, ideally, receiving equal amounts of light on both sides. Standard energy simulation software for solar installations is not fine-tuned for this, and there is almost no field data publicly available for different climates and locations. This is a high risk for the company and future customers, and research is needed to develop the simulation models and obtain production data. The vertical mounting also gives different exposure to wind loads. Indeed, mostly positive for our concept, which will not depend on fastening to the roof or ballast. However, to certify the components and avoid any incidents, research on the effects of wind is needed. The different design also demands research on the strength and durability of the components in the solution. We want to minimize the material usage to reduce climate impact, but at the same time have a strong and durable structure. The project will enable Over Easy to develop a high-quality and highly innovative solar product with a global market. The knowledge developed in the project will be unique and may find other utilizations in solar tech, and create interest and buzz around solar innovations from Norway.