Solcellssystem i svenska byggnader: Förutsättningar relaterade till lönsamhet och montage

Licentiatavhandling, 2016

As a result of decreased solar photovoltaic (PV) system prices, the Swedish PV market has grown rapidly the last few years, with the majority of new capacity installed in buildings. However, the market is still small and this licentiate thesis therefore aims to help facilitating for a continued positive development by adding to the knowledge about conditions related to PV in Swedish buildings. The thesis includes two separate studies. The first study describes how existing PV systems in Sweden are mounted. It comprises 444 systems larger than 10 kWp. A majority of the systems were found on rooftops and only about 10 % on façades. Most of the modules on steep-slope roofs were mounted parallel to the roof, while on lowslope roofs, tilted modules fixed to the roof were the most common, followed by horizontal systems. An increasing share of ballast-only systems on flat roofs could be seen. Historically, PV modules used as shading devices has been the most popular choice for façades, but in 2013, a majority of the façade systems had vertically applied modules. In general, the initial development of a Swedish PV market has been successful and there has been a smooth transition to more and larger systems on buildings. In many ways, this is thanks to a fully developed European market. The second study examines how the profitability of a solar PV investment is influenced by building-specific parameters as well as current economic conditions. Analyses were conducted for 108 electricity supply points in multifamily buildings and 16 in other buildings. First, PV systems were sized to give the highest net present values (NPVs) only considering fuse size and hourly demand matched to simulated PV generation. In a scenario with a 20 % investment subsidy, this resulted in positive NPVs for 56 % of the studied supply points. A scenario with tax rebates based on grid feed-ins resulted in a slightly smaller share of profitable systems. It was shown that this support scheme with tax rebate promotes relatively large systems compared to the subsidy, although with a much higher risk. In a scenario with both support schemes, nearly all systems turned out profitable. Also considering the orientation of existing roofs drastically decreased the share of profitable system among the multifamily buildings, while a large share of the systems in other buildings remained profitable. Lastly, it was shown that the main fuse size and the yearly load had a substantial influence on the profitability.