Batteries are not suitable in storing large amounts of electricity over time. A major advantage of hydrogen is that it can be produced from (surplus) renewable energies, and can also be stored in large amounts for extended periods of time. Short-term electricity storage in batteries for small plants is developing dynamically, however, longer-term storage of larger surplus amounts of electricity requires new types of storage, such as chemical storage in the form of hydrogen.
Hydrogen can be obtained by electrolysis from electricity produced with surplus renewables. If there is a corresponding energy demand, the hydrogen can fulfill it directly. However, it can also be stored in bulk tanks as pressurised gas and retrieved when supplies are low. Hydrogen can also be converted into other energy carriers. Converting renewable electricity via hydrogen into other energy carriers, the Power-to-X concept (PtX), can result into a number of different utilisation pathways. You can find relevant information by downloading the report by ENEA.
THE POTENTIAL OF POWER-TO-GAS download