Qualified Forecast of Ensemble Power Production by Spatially Dispersed Grid-Connected PV Systems

The contribution of power production by Photovoltaic (PV) systems to the electricity supply is constantly increasing. An efficient use of the fluctuating solar power production will highly benefit from forecast information on the expected power production. This forecast information is necessary for the management of the electricity grids and for energy trading. This paper presents an approach to predict regional PV power output based on irradiance forecasts provided by the European Centre for Medium-Range Weather Forecasts (ECMWF). In the first part of the paper we introduce and evaluated different approaches to refine the irradiance forecasts. The second part of the paper addresses the power prediction for ensembles of PV systems. Here, in view of the data handling problems associated with the high number of individual systems contributing to the total PV generation within a region, the identification of representative subsets and representative system characterizations reflecting the power characteristics of the total ensemble is discussed.