And where would you store this energy generated during the day ? We need electricity at night, especially in the winter when it's not windy and it's dark. You can't build batteries to supply the country, that's certainly not technically possible and not financially viable. There have been several studies recently regarding storage and they concluded that it's not viable apart from in small formats such as single houses.
We need a mix - base load from Nuclear and gas then off shore wind where it makes sense. Technology is not at the point yet where we can store massive amounts of power.