> Sun is only present in the summer

Your general point is not controversial (sun/wind are unpredictable). By stating that the sun only shines in the summer,though, people are not going to take you seriously and will miss your point.

The obvious solution to the unpredictability of solar/wind is to couple renewable power generation with short/medium term energy storage capacity. There are many ways to do this, all with their own upsides and downsides. E.g. pumped hydro, grid-scale LFP batteries, etc. Also, long-range interconnects to places with more sun and/or wind.