The Accuracy of PV Power Plant Scheduling in Europe: An Overview of ENTSO-E Countries

The dynamic increase of Europe's installed photovoltaic capacities does not leave any of the stakeholders of the electricity industry unaffected. One of the effects of the inevitable uncertainty of solar power generation, due to solar energy's variable nature, is the increasing significance of the provision of reliable power generation forecasts to make the integration and operation of grid systems including photovoltaic power plants possible, as well as to facilitate the related processes of decision making and planning. This study presents the accuracy of the daily and the intraday scheduling of energy generation in the PV systems of the member countries of the European Network of Transmission System Operators (ENTSO-E) in the period 2013 - 2022. The examined countries showed great variation regarding the accuracy of the scheduling of their PV power plants. Overall, it could be established that Germany and Spain were capable of producing more precise forecasts than the other nations in the study. In their case, the annual downward and upward regulatory needs, as percentages of the yearly energy generation, ranged between 5.6% and 2.3% for the daily, and from 6.1% to 2.6% for the intraday forecasts. In some countries the forecasts demonstrated less accuracy, e.g. in Estonia the annual need for downward regulation nearly reached 47% of the energy generated in 2020, while in Switzerland the yearly need for upward regulation exceeded 42% of the produced power in 2018. The novel, practical contribution of the research presented in this paper is that it determines and presents information related to the accuracy of the ENTSO-E countries' day-ahead and intraday PV forecasting activities that are relevant from a practical perspective to the transmission system operators (TSOs), the main actors of the energy market as well as the decision makers. Furthermore, this information is of help for investors investing in PV power plants not only from an economic perspective, but it may also significantly contribute to the market-related development of the management systems of energy storage solutions related to PV technology.

Automated summary

The accuracy of PV power generation forecasts varies greatly among European countries, with Germany and Spain performing better than Estonia and Switzerland. This study provides valuable information for transmission system operators and decision makers, as it determines and presents the accuracy of ENTSO-E countries' PV forecasting activities.