PV energy could be used to lift water and store it in a large reservoir for use in power generation as it flowed back down.
We have one system of hydroelectric dams that pump water up again at night, when the electricity is cheap. Something like that could be used for times of surplus generation, like surplus solar or wind, etc.
I think it is common technology. Even a single dam can have a lower, smaller reservoir, to be able to pump the water up again from there.
One idea for hydrogen cars, is to use surplus generation to produce hydrogen via electrolysis. It could also be used as storage and turned back into electricity, but i think that the efficiency is not good. No emissions, however.
You need to do a bit of research. Hydrogen for hydrogen powered cars comes from fossil fuels. It's too expensive to produce with electricity. While the resevior system works, just look at how little electricity it actually produces for Germany. I think I saw less than 3%.
This is from eight years ago, "In the U.S., the existing 38 pumped hydroelectric facilities can store just over 2 percent of the country’s electrical generating capacity. That share is small compared with Europe’s (nearly 5%) and Japan’s (about 10%). But the industry plans to build reservoirs close to existing power plants. Enough projects are being considered to double capacity."
Want to guess how many for these "planned to be built" are actually being considered? In California the answer is 0. There are issues with fish, water for farmers and people. I think California has close to 200, and we stopped building them for environmental reasons. One of the last ones they were building is about 2 hours from me. It's one of the ones the environmentalists never allowed to be completed.
While it might sound like it good idea, in practice it doesn't work out that way.