> There is no summer which have had no winds, no winters that have had no insolation or vice versa. The part of "no production" were not meant to be taken lite

> There is no summer which have had no winds, no winters that have had no insolation or vice versa. The part of "no production" were not meant to be taken literally. If you want a more precise statement then let me put it this way: For PV in central europe even an overcapacity factor of 5 would be insufficient to cover the difference between summer and winter. Germany's PV plants produced 7.3TWh during June 2019 and 0.58TWh during december 2018. Wind does look a bit better as far as seasonal differences go (about 4-5x) but it suffers from more short-term variability, so you might need less seasonal storage for it but it would require more medium-term (multi-day or -week) storage compared to solar which is a bit less variable during its peak months compared to wind's peak months.