Storing Power for Weeks

Batteries handle the daily cycle well, shifting afternoon solar into the evening. The harder problem is a long, gray, windless stretch that lasts days or a whole season.

That is the job for green hydrogen: use surplus solar and wind to split water into hydrogen, store it cheaply in large tanks, then burn it or run it through fuel cells when supply runs short. A smarter grid helps too, shifting flexible demand to the hours when clean power is plentiful.