Doesn't do anything to avoid the fact that you have to have coal/gas/nuclear as back-up for when the wind doesn't blow. And this will not have been factored into the lower cost of wind power claimed.
It is only possible to do away with fossil and nuclear partially or wholly if there is vast amounts of wind (>5x) and solar (>2x) capacity installed together with grid energy storage such as vanadium batteries, pumped storage, etc.
