"One alternative to fossil fuels is ‘green’ hydrogen, which can be produced through water electrolysis by using an electric current to split water into hydrogen and oxygen with no greenhouse gas emissions, provided the electricity used to power the process is entirely from renewables. Hydrogen’s high mass energy density, light weight, and facile electrochemical conversion allow it to carry energy across geographical regions through pipelines or in the form of liquid fuels like ammonia on freight ships ... Across sectors as it can be used as a chemical feedstock, burned for heat, used as a reagent for synthetic fuel production, or converted back to electricity through fuel cells. Furthermore, hydrogen’s long-term energy storage capacity in tanks or underground caverns ... makes it one of the only green technologies that can store energy across seasons."