The latest ~15 MW off-shore monsters are up to capacity factors of 60-64% now.
https://www.ge.com/renewableenergy/wind-energy/offshore-wind...
https://www.ge.com/renewableenergy/wind-energy/offshore-wind...
Also that said, andy_ppp is right, or will be soon. If you want to make a dent in our fossil fuel needs on a cold windless day, you'll have giant globs of excess energy on warm windy days, that is simply orders of magnitude more than any practically-costed battery can store. At that point, who cares if electrolysis is only 30% efficient?
That 70% loss defines the lowest possible price difference between buy cheap power and sell expensive. Therefore any other smart consumer or storage has that margin to work against, to compete you out of the market. This is why batteries can work, in some cases. But it is a pure inefficiency that will find a minimum equilibrium.