Hydrogen production is a way for excess electricity from nuclear power to be stored. Is it the best way? In some circumstances it may be.
At the consumer level, when I read about the dangers of lithium batteries catching fire, hydrogen sounds like a better option especially if a vehicle is design to disperse the hydrogen away from the passengers when an accident occurs. Some vehicles have you riding on the lithium battery pack.
Now add tunnels to the mix and consider a lithium battery fire in a tunnel with toxic fumes and the need to add 24 times the amount of water used to put out a ICE fire.
EV batteries are very safe. Yes there are incidents, but there's fewer as automakers learn to make safer packs.
We had a fire in a big parking garage here in Norway. Already many EVs here and not a single battery pack caught fire even though the car interiors burned. Our fire departments probably have the most experience with EVs anywhere in the world, and they consider them generally safe and not hard to deal with when trained for it.
Funny you should mention tunnels, it was recently found that millions could be saved on ventilation on a future tunnel project because there's such a high share of EVs now. There's a tunnel nearby that's very often closed because there's a steep grade and there's always some ICE truck that overheats and catches fire. With EVs that won't be an issue.
Meanwhile, a hydrogen station blew up just a few km from my house. Incredibly loud explosion. Yeah, I think hydrogen cars and stations can be made safe with engineering. Just like Li-ion. But it is fundamentally unsafe. It easily leaks through fittings if they aren't tightened with just the right torque. And when you get the right hydrogen/oxygen mixture it borderline self-ignites.
Many cars are moving to LiFePo as it's cheaper and good enough for most. It's much safer still. Solid state batteries will also be perfectly safe.
In my area hydrogen fuel is ~ $20/kg, and 1 kg ~ 1 gallon of gas.
The high pressure hydrogen tanks are bulky, expensive and have a lifetime.
I think a comparison to CNG is in order.
For a long time there was a push for Compressed Natural Gas vehicles, and many were made. There were ford pickup trucks and police cars, honda had a CNG accord. CNG is 1 carbon and 4 hydrogen - CH4. With a little fiddling, it can be used directly in a gasoline engine. You still need a catalytic converter because the high temperature combustion creates smog (NO)
Natural gas was more widely available (it comes out of the ground), and costs were usually less or at worst similar to gasoline.
The vehicles had storage tanks ~ 3000 psi (much lower than hydrogen). They were bulky and usually took up the entire trunk of a vehicle. The tanks also have a lifetime.
They kind of worked, but just the same, they needed subsidies to survive. Now they are basically all gone.
At the consumer level, when I read about the dangers of lithium batteries catching fire, hydrogen sounds like a better option especially if a vehicle is design to disperse the hydrogen away from the passengers when an accident occurs. Some vehicles have you riding on the lithium battery pack.
Now add tunnels to the mix and consider a lithium battery fire in a tunnel with toxic fumes and the need to add 24 times the amount of water used to put out a ICE fire.