PV-Fokus: Optimization of PV Power Forecasting with Machine Learning Methods Focusing on Low Clouds

Project Summary

Accurate PV power forecasts are essential for the stable and efficient operation of the energy system. The PV-Fokusproject develops innovative machine learning methods to improve PV power forecasting and explores new meteorological input data. A particular focus is placed on high-resolution satellite-based information on solar irradiance and cloud cover, as well as newly developed predictors for the formation and dissipation of low-level clouds. A flexible ML architecture enables the combination of different data sources and models across forecasting horizons, from short-term intraday to day-ahead forecasts, and across different grid levels.

Our Contributions

KIT focuses in particular on low-level clouds, whose rapid and difficult-to-predict development can lead to significant PV forecasting errors. Using high-resolution satellite data, low-level stratiform and convective clouds are automatically identified and their development is analysed. Machine learning models and explainable AI methods are used to identify the key environmental drivers of cloud formation and dissipation.

The resulting insights are initially used for intraday forecasting and subsequently combined with numerical weather prediction models to enable day-ahead forecasts. In this way, PV-Fokus contributes to more accurate PV power forecasts and a more reliable integration of solar energy into the electricity grid.

Situationen mit niedriger Bewölkung über Deutschland, die zu Fehlern bei der Vorhersage der PV-Leistung führen können. Links: Nebel und tiefe Stratusbewölkung am 4. November 2024. Rechts: Konvektive Cumulusbewölkung am 16. Juni 2025. Beide Bilder wurden vom Satelliten Meteosat Second Generation aufgenommen und von EUMETView heruntergeladen.
Low-cloud situations over Germany that can lead to errors in PV power forecasts. Left: Fog and low stratus on 4 November 2024. Right: Convective cumulus cloud cover on 16 June 2025. Both images were acquired by the Meteosat Second Generation satellite and downloaded from EUMETView.