Increasing the Proportion of Winter Electricity through Design Optimisation of Photovoltaic Roof Systems

At higher latitudes, one half of the year delivers a significantly lower energy yield due to the seasons. As a result, expensive seasonal storage systems are built up to close this energy gap. In Switzerland and other alpine countries, open-space alpine plants are currently being planned to supply electricity specifically in winter. In the current work, we show that the proportion of winter electricity can also be increased with PV roof systems in the Alps by means of design changes, so that electricity can be produced much more cheaply and closer to the consumer in winter. For this purpose, bifacial modules are proposed vertically with ground cover ratios in the range of 0.5 to 1 and, depending on the conditions, mounted either on flat roofs in east/west orientation or on pitched roofs oriented as far as possible to the south. We show that the winter electricity can be increased by about 30% compared to the reference, but at the expense of a reduction in the total annual yield.