They’ll possibly even need two tons :P

I think probably not for personal vehicles (which, I still believe we should be phasing out private car ownership anyway, and hydrogen makes even less sense for even smaller vehicles like electric bikes), but for large vehicles like trucks, trains, ships and planes, especially for remote areas or long nonstop trips, the higher specific energy of hydrogen over batteries (at least, current battery tech) will become beneficial, even though hydrogen energy storage is less energy efficient that batteries. It could potentially even beat out overhead wires in some cases, namely infrequent and/or long routes, because the losses through a wire a lot higher than most people assume, and many of those losses are generally constant per distance, no matter how many vehicles are using it. Not to mention, maintaining point sources of hydrogen is likely cheaper and easier than maintaining an extensive network of pantograph wires crisscrossing the country.