Hydrogen has good energy/kg, but it has really poor energy/l. Buses are mostly empty space so they more volume limited than weight limited. Battery powered buses are already far more common than Hydrogen buses and the trend will accelerate quickly.
In Europe, battery powered trucks can carry a heavier load than diesel trucks. The weight disadvantage of a battery powered truck is about a tonne. The batteries weigh a lot more than a tonne, but so does the engine, transmission and fuel in a diesel truck. The difference is about a tonne. In Europe, they allow battery trucks to weigh two tonnes more than diesel trucks, so... In America battery powered trucks have a 1000 pound weight limit increase.
Green hydrogen is always going to cost about 10x as much as electricity. Using electricity to electrolyze water, compress the hydrogen, transport the hydrogen, strip off the electrons in a fuel cell, charge a battery and then drive a motor is necessarily a lot less efficient than using than skipping 4 of those steps to charge a battery directly.
And truckers don't care about fuel density, they care about costs.
In Europe, battery powered trucks can carry a heavier load than diesel trucks. The weight disadvantage of a battery powered truck is about a tonne. The batteries weigh a lot more than a tonne, but so does the engine, transmission and fuel in a diesel truck. The difference is about a tonne. In Europe, they allow battery trucks to weigh two tonnes more than diesel trucks, so... In America battery powered trucks have a 1000 pound weight limit increase.
Green hydrogen is always going to cost about 10x as much as electricity. Using electricity to electrolyze water, compress the hydrogen, transport the hydrogen, strip off the electrons in a fuel cell, charge a battery and then drive a motor is necessarily a lot less efficient than using than skipping 4 of those steps to charge a battery directly.
And truckers don't care about fuel density, they care about costs.