Last year the EU produced 42% of its electricity with renewables. 18.9% of it with wind and 8.0% with solar. There is also a 24.5% share of nuclear, which is probably going to stay stable. That leaves 31.9% fossil fuels. So we have to a bit more then double wind and solar installations in the EU. That is entirly possible to do. Especially with offshore becoming as cheap as it is and we still have a lot of rooftops without solar.

About storage there is a wonderfull thing called electricity grids. The worst days for wind last year wind made up a bit less then 10% of electricity production. That is of an average of 18.9% over the entire year. For solar it is worse in wind, but luckily wind makes up a lot of the rest. Combined that means that the worst days still have 13% wind + solar EU wide. So about half of average. As soon as you extend it to a week the worst ones are at something like 17% of wind + solar. So with a strong enough grid we get pretty close. As soon as you add a bit of storage to the grid and overbuilt wind and solar a bit, renewables work just fine.

Honestly we are pretty close to solving it. Most EU countries are at over 50% clean electricity today. Even better Putin caused massive built ups of clean power generation. We are going to be fine, if we continue in that field.