* There isn't a fuel distribution system. The reason BEVs work is because everywhere has power, setting up power distribution is generally just plugging into the local grid.
* Hydrogen escapes any container it's placed in. That's a pretty hard thing to deal with. Most approaches have looked at chemically binding hydrogen to something in order to keep it from escaping, but that, as you can imagine, is expensive. The other option is onsite electrolysis, but that's rather expensive to pull off.
* Speaking of electrolysis, while we can get hydrogen from many sources, the one we are likely to actually use isn't electrolysis but rather natural gas and oil. Why is that? Because electrolysis is inefficient (about 20% efficiency IIRC edit I recalled incorrectly. Electrolysis has a ~70% effciency).
So you have a hard to store fuel, without a distribution network, that may be coming from fossil fuels anyways. -So why do major companies like Toyota love hydrogen? Because it doesn't require them to make any major changes to their fleet. You can get a lot more miles out of the basic combustion engine design and you don't need to retool all your product lines.- edit I was wrong, looks like most hydrogen vehicles are fuel cell based.
Now, that isn't to say that hydrogen has no place in the future. I think because of it's energy density hydrogen will likely play a role in the airline industry. It may even be possible that hydrogen ends up finding a place in long range shipping. However, hydrogen in a consumer car is, IMO, DOA. BEVs already exist as do their charge networks.
Toyota Mirai (their hydrogen powered car) is fuel cell vehicle, it uses hydrogen to power electric motors.
Actually it's pretty efficient. According to wikipedia, efficiency ranges from 70% for the cheaper method, to 80% with more expensive catalysts. Theoretical efficiency is 94%.
Electrolysis is only a small factor.
It's all of the other required bits that makes Hydrogen so inefficient. Transportation, building up pressure, etc. Hydrogen if you compare things simply is more efficient than gas/diesel. However, gas/diesel is pumped out of the ground. Meaning, a lot of the energy needs for gas/diesel are already there.
- Transport. You can either transport hydrogen via pipelines or simply produce it via electrolysis in-place. You have to get the electricity to the destination somehow, so this doesn't really differ between electric and hydrogen cars.
- Building up pressure. Energy required to build up pressure is related to how much the volume is reduced (force x distance and all that...) Conveniently water is almost incompressible, so you can raise the water to the desired pressure cheaply before you electrolyse it. https://en.wikipedia.org/wiki/High-pressure_electrolysis says this can be done at 97% efficiency.
Why would there be a combustion engine in a hydrogen car? I expect that there would be a fuel cell powering electric motors. Are there other ways to use hydrogen in cars, other than fuel cell? I'm not an expert.
Doesn't look like a great path forward - deep internal engine parts need to be modified (no "hydrogen kit" for existing cars), they emit NOx emissions (so not zero-emission), and you have all the disadvantages of a combustion engine.
However, combustion engines have 100 years of development behind them and a proven track record of reliability (probably billions of running hours by now). Fuel cells are still newish - "the devil you know". This would also keep mechanics employed and keep dealership service bays busy... kind of a perverse incentive, but it's there for sure.
It may be a stop-gap, or useful for certain situations (long haul trucking is mentioned). It could be part of the tapestry of technologies needed to move to a more renewable-based future.
- The trade-offs work in favor of EVs, hydrogen has a similar distribution problem to gasoline (fueling stations).
- Hydrogen requires production somehow, electricity we already have the grid and people can charge at home
- The things hydrogen is good at (lighter weight than batteries, faster refueling) are starting to become less relevant as battery and charging tech improves.
- The argument that you need an equivalent charging infrastructure isn’t really true since you only need that for long tail long range trips (and also we have that now).
The reason I personally dismiss people talking about hydrogen or supporting it (Japanese automakers) is it ignores the obvious current success of EVs in addition to the arguments above and it often feels like a disingenuous argument in bad faith. Specifically, someone is anti-EV and bringing up hydrogen as misdirection to make some EV thing harder to implement.
The success and market uptake of hydrogen vs. EV seems to be empirically obvious at this point. I suspect because EVs could get over the chicken/egg charging infrastructure issue because early adopters could just charge at home (and most trips are short range).
To add: Hydrogen stations are fairly unique. It's really expensive to build such stations (millions). Plus heavy restrictions on where they can be placed. Putting up a charge station is really cheap in comparisons (think it was something like 10k for on a public street with 2 charge ports), plus you can place them pretty much anywhere (way less safety restrictions).
What I dislike about EVs is how expensive they're to charge if you're not using your own electricity. At least, that's the situation in NL.
People that own EVs have to deal with the lack of supporting infrastructure, and have a vested interest in steering public opinion to go in a direction they have already personally committed.
That doesn't necessarily mean they're wrong about the future, just that they have incentives that could cause them to hang onto some bad ideas because they adopted early (and want to save face).
I do wonder how much the driver needs to rest, if high speed charging works during the driver's breaks. Could use overhead chargers.
Ammonia is another alternative.
The problem with hydrogen is there is no hydrogen available, we have to first generate it and distribute it to cars. So far this process is much more expensive than generating and distributing electric power.