Combine with rooftop solar for total grid disconnect, or stay connected to the grid and sell your leftovers for whatever pittance you can get AFTER you've accounted for your night time and grey sky needs.
I suspect, given the way power companies are starting to punish rooftop solar in some locales, that a new service industry might emerge offering a mobile rapid charge service as more and more people elect to abandon their connection to the grid entirely.
Or form a cooperative with your neighbours. Lots of solar panels on lots of roofs, a big battery bank and just one grid connection per 20-30 houses.
Affordable high capacity batteries are a real game changer, given their intermittent nature of the most mature renewables. Solar only works during the day, and wind only when wind speeds are neither too fast or too slow. Wave and tidal generators, not tied to rare geographic features, have a bad habit of being smashed to smithereens whenever the weather gets a little too boisterous.
One beauty of a fully mature portfolio of renewable energy sources is that the idea of excess/underutilised capacity ceases to have any meaning. Since running costs are extremely low, it begins to make sense to do energy intensive things like use desert sunshine to melt Boston's snow and use that to water lawns in Las Vegas.