During winter, when electricity needs are high, northern Europe maybe gets total of 0-6 hours of sunlight, and most of is not the optimal angle or intensity. It's also often overcast, so solar barely generates power.
On the worst winter days, when its -5F, and the energy needs are the highest, there is also no wind.
The Baltic Sea also freezes and there is barely any tidal movement.
There isn't really a renewable that works for Northern European energy needs during winter. Hydro is the exception but it's geo based you can't build unlimited hydroplants and also during winter the water levels are not the highest.
On the worst winter days, when its -5F, and the energy needs are the highest, there is also no wind.
The Baltic Sea also freezes and there is barely any tidal movement.
There isn't really a renewable that works for Northern European energy needs during winter. Hydro is the exception but it's geo based you can't build unlimited hydroplants and also during winter the water levels are not the highest.