I'm assuming you're asking because the electricity required to generate the hydrogen to power the car would be (much) more efficiently used to directly power th

I'm assuming you're asking because the electricity required to generate the hydrogen to power the car would be (much) more efficiently used to directly power the car. ie. electricity is being used as a process mid-point rather than end-result. I hear a bit of cynicism about hydrogen being touted by traditional automotive and fossil fuel companies because the business case around it is essentially the same as fossil fuels, where re-charging an electric car can be done at home "for free" (pending a number of dependencies being met), and I agree that it could be a half-step forwards rather than a full-step. But I also believe that it's best to have more than one option, and there are likely to be wildly varying use cases in which each option can an obvious stand-out for different use cases. What other trade-offs are there in hydrogen vs electric engines? (dependence on rare-earths being one negative on the electric side, but are there also rare-earths required for hydrogen engines or the generation of hydrogen?) What are the use cases? city driving, country driving, buses, trucks, towing, rail, light aircraft, passenger aircraft, military.