That's true for a lot of heavy equipment. A lot of ships use diesel generators to power their electric engines. Same for a lot of mining and construction equipm

That's true for a lot of heavy equipment. A lot of ships use diesel generators to power their electric engines. Same for a lot of mining and construction equipment. Likewise, most hydrogen vehicles are basically a fuel cell powering a tiny battery powering an electric motor. Fuel cells aren't great at variable output so it's easier to just put a battery in between. That also makes fully electrifying these things less off a technical challenge and more of a battery cost challenge. Mostly size and battery density isn't that big of a deal even. There's plenty of room in a large heavy vehicle to put some batteries. Even if they weigh a few tons it's not necessarily that big of a deal. Except of course if you need to go half way across the globe with a ship. But shorter range of up to 100-200 nautical miles if very doable now. A big mining truck has plenty of space and they are big and heavy anyway.