[Sprintey]

Toyota HQ locally was in trials with the Mirai, which is an existing Hydrogen fuel cell car.

BMW tried a different path, burning it it a huge V8 7 series on a trial.

It's probably true to say that it will take multiple different approaches to replace fossil fuels.

The big question for all of them is what is the EROEI (energy returned on energy invested)? Can any of it match the 100:1 of early oil? I think we under 10:1 currently and it's getting harder to find reserves (deep ocean, having to process tar sands, fracking etc), so do any of the alternatives feature a higher EROEI once all their manufacture, use and recycling are taken into account?

rough rule of thumb, EROEI > 5 is required to sustain a society, >10 to sustain a complex industrial one.