You got to look at both efficiency and storage costs. Batteries are really expensive but efficient. For short term storage batteries make more sense because sh

You got to look at both efficiency and storage costs. Batteries are really expensive but efficient. For short term storage batteries make more sense because short term efficiency affect economics more. But when you store long term that storage needs to be cheap. Hydrogen or a synthetic fuel derived from hydrogen gives you that. There are also use cases where batteries are too heavy. For long flights batteries are too heavy but hydrogen will work. After all plenty of rockets use hydrogen fuel, none use lithium-ion. Then there are plenty of industrial process which can use hydrogen. E.g. a lot of coal is used as a reducing agent when producing silicon, iron etc. This cause emissions when creating solar cells e.g. By using hydrogen as a reducing agent instead we don’t get CO2 emissions.