Earlier quoted context omitted.
Do you have sufficient battery capacity to power your grid through a 90th percentile worst case scenario solar outage? 95th? 99th? How long can it go without running coal and gas? Nuclear works when you want it to. Solar and wind work when they want to. That's a very big difference when you're producing the electricity people rely on to live their daily lives.
It's a very common mistake to think that batteries are to be used to get to a 100% renewable grid. Hydrogen can be much cheaper for (say) the last 10%, because (1) hydrogen has very low capital cost per unit of storage capacity, and (2) the efficiency hit of going through hydrogen vs. batteries is less important when it's just 10% of the total. Think of batteries and hydrogen as analogous to cache memory and main mem…
Basically all hydrogen comes from fossil fuels. It's just natural gas with extra steps.