The high electricity production values of PV roof systems can be attributed to the continuous expansion in recent years and the excellent irradiation conditions. Over long periods in 2019, electricity yields were slightly above the long-term average for 2012 to 2018. As a result, around 2.5 percent more electricity was generated in 2019 than the multi-year average. The largest specific yields were observed in Baden-Württemberg, Bavaria, and Saxony with over 1,100 kWh/kWp. In northern Germany, the specific annual yields of PV roof systems amounted to almost 1,000 kWh/kWp.
In our study, we concentrated on PV roof systems with a nominal output of up to 30 kWp, as these systems account for around 90 percent of the PV systems installed in Germany, according to data from the Federal Network Agency. Also, these systems generally do not have a professional quality assurance and maintenance concept and supervised remote monitoring systems are also not standard in the system class, especially for roof-mounted systems up to 10 kWp. In principle, the yield data can also be transferred to a larger rooftop or open space systems. Still, due to the larger service and maintenance budget, it is to be expected that these systems should generate somewhat larger reference yields.
This study aims to evaluate the electrical energy yields of photovoltaic roof systems in Germany for the 2019 operating year, to enable operators to compare the energy yields generated with the yields expected for their PV system. This allows every system operator to check whether his solar system has produced stable yields or whether it is worthwhile to have his PV system technically examined for optimization possibilities due to too low yields.
Further information on the study, on research in the field of yield analysis of photovoltaic systems and contact details, can be found on our ↦ yield studies page.