In 2014, ZSW substantially expanded and improved its range of operational feed-in forecast products. In addition to wind output forecasts, ZSW produced its first photovoltaic feed-in forecasts for geographically distributed PV portfolios, both in the four German balancing energy zones and nationwide.
The normalised root-mean-square error (nRMSE) in the installed capacity is routinely used to evaluate the forecast quality of wind and PV feed-in. A 2.9% nRMSE applied to Germany in ZSW’s 2014 PV power forecast (see chart). As part of the WindSage project funded by the German Federal Ministry for Economic Affairs and Energy (BMWi), wind power forecasts were also significantly improved. With the inclusion of data from additional weather models, the nRMSE was reduced from approx. 4.5% to 3.4% in German forecasts for the year 2014. A further reduction of the forecast error and optimization of very short-range wind and photovoltaic power forecasts can be expected from the WindSage project. The BMWi-funded VORKAST project predominantly focuses on the development of new methods for very short-range wind and PV power forecasts suitable to optimise the operation of hybrid power plants. These developments will lead to further improvements of ZSW wind and PV power forecasts.