Batteries (except flow batteries) must be scaled linearly with the desired storage capacity. Hydrogen storage on the other hand only requires a container to be

Batteries (except flow batteries) must be scaled linearly with the desired storage capacity. Hydrogen storage on the other hand only requires a container to be scaled with the desired capacity (square-cube law) while the conversion machinery, i.e. the power rating of the storage, can be scaled independently. Building batteries for seasonal energy storage would require huge amounts of raw materials. Building hydrogen storage requires nothing because you can reuse salt dome caverns previously used for natural gas.