Long-term patterns of European PV output using 30 years of validated hourly reanalysis and satellite data

TLDR

Solar PV is rapidly expanding worldwide, raising challenges for grid integration because its output varies with complex weather, making accurate modeling difficult. The study demonstrates how MERRA, MERRA‑2, and CM‑SAF SARAH datasets can be used to generate hourly PV simulations across Europe. The authors validate the simulations against metered data from over 1,000 PV systems and national aggregates, correct systematic bias, analyze thirty years of simulated outputs, and provide the code and data through an interactive web platform. The simulations show that satellite data yield slightly higher accuracy while reanalysis data offer greater stability, and that expanding PV deployment significantly alters net power demand, system adequacy, and ramping needs with varying effects across European countries.

Abstract

Solar PV is rapidly growing globally, creating difficult questions around how to efficiently integrate it into national electricity grids. Its time-varying power output is difficult to model credibly because it depends on complex and variable weather systems, leading to difficulty in understanding its potential and limitations. We demonstrate how the MERRA and MERRA-2 global meteorological reanalyses as well as the Meteosat-based CM-SAF SARAH satellite dataset can be used to produce hourly PV simulations across Europe. To validate these simulations, we gather metered time series from more than 1000 PV systems as well as national aggregate output reported by transmission network operators. We find slightly better accuracy from satellite data, but greater stability from reanalysis data. We correct for systematic bias by matching our simulations to the mean bias in modeling individual sites, then examine the long-term patterns, variability and correlation with power demand across Europe, using thirty years of simulated outputs. The results quantify how the increasing deployment of PV substantially changes net power demand and affects system adequacy and ramping requirements, with heterogeneous impacts across different European countries. The simulation code and the hourly simulations for all European countries are available freely via an interactive web platform, www.renewables.ninja.