The ERA5 reanalysis data (1979-2019) has been used to calculate the hourly country aggregated wind and solar power generation for 28 European countries based on a distribution of wind and solar farms which is considered to be representative of the 2017 situation. In addition a corresponding daily time series of nationally aggregated electricity demand is provided. The datasets have been produced to investigate the inter-annual variability of the three weather-dependent power system components. When citing this dataset please refer to the publication: Sub-seasonal forecasts of demand, wind power and solar power generation for 28 European countries (see Related CentAUR publications)