More than 90% of hydrogen fuel produced in the USA comes from splitting methane using electricity produced from fossil fuels. So, right now, it makes no sense to use hydrogen fuel, not for environmental purposes, and not for energy efficiency because you might as well use the already-existing methane instead. Not wind, nor Earth-based solar, are never going to be able to form the primary components of humanity's electrical grid. The only way hydrogen fuel makes sense is if we use nuclear power to do the splitting, and we split sea/salt water, not fresh water.