The Fraunhofer Institute measures systems while they are running. The results are then analyzed and evaluated. Within 24 hours, the monitoring process highlights not just deviations from the forecast yield values of the system, but also the causes of errors, such as problems with the inverter or shading of the panels.

The evaluation routine developed by the Fraunhofer ISE delivers the solar irradiance, yield and the performance ratio of each system daily. Through performance controlling, we can ascertain whether the forecast yields of the system are being met. High quality PV systems reach a performance ratio of over 80%.