I... put politely, don't understand how manufacturers can make that claim, it depends on exogenous factors. That said, you're right, the newest turbines are impressive structures and more consistent at their job.

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?