I was on the Kaitaki, on the way back from a kayaking trip in Abel Tasman, when it had it's breakdown, so I know better than anyone the consequences of these ferries failing, but the project to upgrade them was at more than 2x the original budget, and set to increase further when the new government pulled the plug.
If Labour and Kiwirail had managed to keep the project under budget, we'd still be getting the boats, but the project had blown out by more than the cost of the vessels themselves.
It happened after a driver allegedly fled from police and crashed his car on a rural road, before breaking into a stranger's home and threatening the occupants.
Try and find out the cost per KG for hydrogen, it's almost impossible. If you lease a hydrogen car, the fuel is included in the lease, and I've found it very hard to find a retail price for the stuff, but every price I have seen indicates it's phenomenally expensive, meaning a hydrogen vehicle is more expensive to run than a petrol vehicle.
Here's some actual numbers, $200 usd to fill a Mirai, which will give you about 600km of range.
As to the battery swap thing, it took decades, and an EU ultimatum, for everyone to agree on a charging standard, what do you think your chances are of everyone agreeing on a battery design?
This is a stupid idea, and there's a very good reason why nobody but them is doing it.
Both swappable batteries and hydrogen are dead end technologies, at least as far as road vehicles are concerned. The economics of hydrogen will never compare to an EV, the range is only similar, and the charge rates of modern EVs have made the refuel time less significant.
With battery swaps, the logistics and capital required to build a charging station, which any EV can charge at, compared to a battery swap station which only one model of vehicle can use, mean this will never be widespread.
Meanwhile, most EVs will go from 10-80% capacity in about fifteen minutes.
Weedeater is the one I usually hear.