wind is at around 4-5% of total electricity production in Europe (20-25% in Denmark, above 10% in Portugal, Ireland, Spain, close to that in Germany). The goal is to get in to around 20-30% of electricity generation overall, which will mean close to 40% in some countries.

The technical solutions to wind integration are known - it mainly involves reinforcing the grid to link the wind-producing regions to the rest of the network, and introducing more intermittency management tools in the system.

Spain regularly deals with more than 50% of its electricity coming from wind; it has also dealt with that proportion falling brutally from 50% to very little in a short period (because winds were too strong and triggered the safety cutoff speed of turbines).

The capacity to deal with periods of low winds already exists - it is the current system, which will simply be used less when the wind blows. There's a hell of a lot of hydro and gas in the system, and these work fine to step in when wind is absent.

In the long run, we're all dead. John Maynard Keynes