Underground hydrogen storage is a suitable method to solve the hydrogen storage problem. Hydrogen can be stored underground when surplus energy is generated and release when the demand increases. Water electrolysis can transfer the extra energy to hydrogen with the advantages of low cost, high efficiency, and environment friendly. But the storage of hydrogen gas is a problem, aboveground storage needs strict requirements because of the low density, low solubility, and high diffusivity of hydrogen. Underground storage can avoid these problems. There are so many salt caverns in Southern Ontario, which are constructed by injecting water into the underground rock salt layer. The high salt content in the solution can prevent the solution of hydrogen. The plastic deformation of salt caverns can prevent the leakage of hydrogen. In this study, energy consumption and demand are balanced for hydrogen production from water electrolysis and storage in salt caverns. The potential of hydrogen storage in salt caverns is evaluated. A simple model is established to simulate the electrolysis process.