East-west vertical photovoltaic system with stabilising effect
Jul 14, 2022
Scientists from the University of Applied Sciences in Leipzig have studied the potential impact of large-scale deployment of west-east facing vertical photovoltaic systems in the German energy market. They found that such installations could have a beneficial impact in stabilising the national grid compared to conventional ground-based PV plants, while allowing for greater integration with agricultural activities.
The researchers used the EnergyPLAN model, developed by Aalborg University in Denmark, which is commonly used to simulate the hour-by-hour operation of national energy systems including the electricity, heating, cooling, industrial and transport sectors. The study helps to predict what the German energy system would look like by 2030 if more vertical PV systems were deployed.
"We systematically changed only two parameters: firstly, the share of installed power for different PV models," the academics said, noting that solar trackers were not considered. "Secondly, two scenarios were considered - integrated or not integrated large-scale energy storage."
For a conventional ground-mounted system, the scientists considered an estimated power generation using a 20-degree tilt angle and an average of 1020 Wh/W. For a west-east facing bifacial vertical system, they assumed a bifaciality factor of 90% and an annual generation of 999Wh/W, while for a north-south facing vertical system, the annual generation was set at 926Wh/W.
In our model, electricity demand increases to 1214 TWh/a in 2030, based largely on assumptions about energy efficiency and fuel transition," they said. The biggest uncertainty is the heating of buildings and industry."
They also take into account the higher cost of double-sided panels and the fact that the installable power per unit area for vertical installations is reduced by shading effects, as module rows are typically spaced between 8 and 12 metres apart, which in turn increases wiring costs.
They say, "The additional cost of the land itself must be apportioned to the benefits of preserving agricultural land use or due to the promotion of biodiversity."
The scientists found that vertical PV systems can shift solar production to times of higher electricity demand, with more power available in winter, thus reducing solar cutbacks.
