The IEA says that today's offshore wind market "doesn't even come close to tapping the full potential – with high-quality resources available in most major markets".
It estimates that offshore wind has the potential to generate more than 420 000 Terawatt hours per year (TWh/yr) worldwide – as in more than 18 times the current global electricity demand. One Terawatt is 114 megawatts, and to put it in context, Scotland it has a population a little over 5 million and requires 25 TWh/yr of electrical energy.