Hydrogen storage is significantly more difficult than LPG.

The pressures need to be higher, which means stronger and more expensive tanks. It also means we must input more energy to compress the gas for storage.

Hydrogen is also significantly smaller and more reactive than NG. Which also means the tanks are more expensive as they need to be resistant against corrosion. Additionally, the valves and seals in the system need to be of a higher class as hydrogen is more prone to leak.