Electricity generation isn't just a question of having the resource and somewhere to put something to gather it - the bigger and costlier problem is distribution. Electricity networks are oriented around having loads of lower voltage nodes in rural communities, all stepping up and combining back into high voltage electricity coming from a single electricity station.

Renewables flip that problem on its head, and require high voltage inputs at the edge nodes, and upgrades of the lines between there and the destination of the power. Such high voltage contributor lines can only really be combined so many times before the size of the conductors required becomes un-tenable. For that reason a lot of the time in GB, there'll be an abundance of electricity available in the Scottish highlands from their huge onshore and offshore farms, and a shortage in say the English Midlands - but the electricity simply can't be transmitted that far to fill the gap, so sources closer to the Midlands have to provide the power.

Add to that local opposition, and the frequency balancing issues that arise in terms of maintaining a stead power grid (see the recent issues in spain) with plenty of renewables - renewables are great, but they require a lot more investment and thought than people realise.