A few weeks ago there was a link paper by an green energy investment advisor firm posted on HN. It displayed the economics pretty clear. Depending on location, a battery with capacity up to 6 hours can be economical viable as long they get a full discharge (ie they sell all the energy) each day at peak price and can charge when the price is at the bottom. It depend in location, how big the difference is between bottom and peak price, and how long that the price sits at each price point.
For wind all those assumptions are wrong and thus won't work. You do not get a daily discharge where you can sell all the energy, you don't get a significant price change each day where you can utilize the price difference, and the capacity needed is a few orders of magnitude greater. Green hydrogen is one of the bigger bets people are hoping on, and right now it only cost several times more than nuclear. Except rather than using nuclear countries are burning fossil fuels because that is cheaper, and thus coal.
