Using hydrogen made from electrolysis of water (using solar/wind inputs) as a fuel for electricity generation is basically a futile cycle, and the only advantage would be temporal storage. For short term storage (hours/days) batteries are far more efficient. For long term storage, hydrogen is a bad idea other than as feedstock for production of longer-chain hydrocarbons (Fischer-Tropsch synthesis) or methane (Sabatier reaction).

The more obvious immediate use (not mentioned in article) is for steel production by the H2-DRI-EAF method, the direct reduction of iron in an electric arc furnace.

https://bellona.org/news/industrial-pollution/2021-05-hydrog...

> "Iron ore is reduced with hydrogen while in a solid state, hence the name direct reduction, to produce direct reduced iron (DRI) called sponge iron. Sponge iron is then fed into an EAF, where electrodes generate a current to melt the sponge iron to produce steel. Some carbon is needed so that steel can be produced. This carbon can come from pulverized coal, biomethane or other biogenic carbon sources."

The other obvious use is as a replacement for natural gas feedstocks for ammonia production via the Haber-Bosch process, and there are similar uses in traditional petrochemical production where hydrogen is often used in various large-scale organic chemistry transformations with names like 'hydrocracking' (breaking apart long-chain molecules) and 'dearomatization' (converting benzene to cyclic hydrocarbons), see:

https://www.linde-gas.com/en/processes/petrochemical-process...

Direct air capture of carbon dioxide and conversion to methane via addition of hydrogen (Sabatier process) as a means of making rocket fuel for Starship, that's also an idea Musk should take up. That's how you'd have to fuel a spaceship on Mars as well.