Operational Forecast of PV Production

Enecolo AG, Lindhofstrasse 52, 8617 Monchaltorf, Switzerland ABSTRACT: The paper shows an example of an operational PV production forecast for large PV power stations. Radiation forecast based on GFS/WRF model is used as input of the PV yield control tool Spyce. The uncertainty is calculated with a statistical model based on existing examinations. A way to eliminate the bias of the models is shown. The service will be further developed. Keywords: PV production, weather forecast, solar radiation 1 INTRODUCTION Solar radiation and PV production forecasts are becoming increasingly important as solar produced energy is growing strongly. Within the next few years the share of solar produced energy injected on power grids during peak hours will become noticeable in some areas of the world, especially where legislation encourages the deployment of increasingly large solar power plants. In future, solar produced energy will be sold on the spot market. Short term forecasts of the solar produced energy then will be crucial to allow safe deals on the spot market. Within the ongoing project IEA SHC Task 36 „Solar resource knowledge management“ [1] Meteotest validates and enhances their operational global radiation forecast based on GFS input and local area weather forecast model WRF [2]. In another conference paper this model is benchmarked with other models at three sites in the USA [2]. 2 SPYCE FORECAST SYSTEM 2.1 Satellite PV yield control and evaluation (Spyce) Spyce forecast is the implementation of radiation forecast in the PV yield control system Spyce (www.spyce.de). The standard service of Spyce calculates the PV production of the previous day by using measured global radiation (at ground or by satellites) and simulating the PV production. The simulated values are then compared to measured. If they differ statistically users are informed. As an additional and new service forecasted radiation is used as input and the power production of the two following days is calculated (Figure 1). Within the algorithmic chain also direct normal irradiance and tracked radiation (single and two axis tracking) will be calculated and delivered to the user. Further software options are included in the service like the possibility to define losses due to string or tracking malfunctions.