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What are your views on hydrogen powered vehicles?
Do you think they will be the next big thing, or end up being impractical in the long run?
Do you think they will be the next big thing, or end up being impractical in the long run?
For ground vehicles? Totally impractical, since we've got to set up massive refining, distribution, and storage networks for an element that's pretty difficult to store and pipe around. When you're looking at needing to invest hundreds of billions in infrastructure before hydrogen cars even start to approach the utility of petrol ones, battery electric cars look like the more practical alternative, since electricity is dirt cheap and already available everywhere. Batteries are also much greener, since battery charging and discharging is a lot more efficient than the fuel cell cycle.
But where hydrogen fuel could have a future is in air travel. You can build conventional jet engines that burn hydrogen, the required infrastructure buildup is much smaller, and with the energy densities we're talking, I highly doubt that batteries are ever going to be able to handle long haul flights.
Unlike gasoline, hydrogen can be produced locally, at least in places with good access to fresh water.
Joe Scott did a video on hydrogen fuel cell cars a while back, where he explains some of the advantages/disadvantages/challenges of both fuel cell cars and battery cars. I think the most important takeaway from the video is that fuel cell cars can coexist with battery cars, and while they don't have all the advantages of battery cars, they do have some of the advantages of gasoline cars.
In addition to air travel, another interesting area for hydrogen is marine shipping. Shipping contributes about 3% of carbon dioxide emissions and often uses very dirty fuel. I don't know how much of a push there is for hydrogen technology on ships but I found this (slightly old) article on the topic.
But there's a reason there are so many gas stations, namely the millions of other drivers that also need to fill up. 140 stations in California gives you about one station for every three hundred thousand people. There's going to need to be tens of thousands of stations nationwide before hydrogen vehicles are anything but toys for the rich.
I mean, charging stations both exist and are way, way more common than hydrogen refueling stations. Any business with parking can get in on the game by dropping a few grand, whereas with hydrogen, you basically need dedicated buildings.
Right, but regardless of if it's coming from renewable sources, using the electricity directly, i.e. to charge BEVs, is greener since it uses much less of it to accomplish the same goal, leaving more available to replace carbon-generating sources in the grid.
That's just not true. Leaving out the fact that hydrogen generation is almost entirely done by steam reforming natural gas, which directly releases carbon into the atmosphere, the reduced efficiency compared to BEVs means that, even if you're using electrolysis, if the energy to produce the hydrogen is coming from fossil fuel plants, you're doing worse on emissions than a gasoline car. The electricity to hydrogen to fuel cell to motor efficiency is about 25-30%, and the efficiency of large scale fossil fuel plants is around 40%, so you're talking about 12% overall efficiency, compared to 20%ish for ICEs. BEVs do better than either running off of fossil fuels, since they're usually more than 75% efficient, so you get at least 30% efficiency in using fossil fuels for motive power.
Between the required infrastructure buildup, the energy inefficiency, and the storage and distribution problems, I think it'd end up being better to just use biofuels for the edge cases. Not as sexy and futuristic as hydrogen, but more doable with existing infrastructure and vehicles, and if it's less than 10% of vehicles that need to be chemically fueled, existing ethanol and biodiesel production should be more than sufficient.
I am not a fan of the technology. I mean there could some specific uses cases where H fuel cells are ideal, but not in cars. For one thing it would keep the refining and distribution of fuel a thing. Also, hydrogen comes mostly from natural gas currently, so that keeps fracking going.
I greatly prefer batteries. For one thing you can easily generate the power yourself, which helps end the ability of giant companies to set the price of your fuel. I can’t find the definative link now, but I have read that the theoretical maximum efficiency of the H fuel cell system is lower than that of lithium batteries, in a car.
Well, hydrogen can be produced from water via electrolysis, but this is only about 80% efficient.
The problem with that though is that if we're already using elctricity to generate hydrogen, why not just use electricity directly? Hydrogen would have to be substantially more efficient than electricity to make up for the distribution networks required, and electrolysis is more expensive and time consuming than fracking or direct hydrogen gathering unfortunately.
There's actually been a recent development in solar panels that generate hydrogen instead of electricity. It's not yet efficient enough to be practical, but it would solve much of the distribution issue, and would also provide, in stored hydrogen, a power source that doesn't depend as entirely on advances in batteries.
Hydrogen is basically only useful as a battery. It takes energy to produce it, and it releases energy either through burning it or by passing it through a fuel cell. There's no such thing as a hydrogen mine we can tap from. There is no abundant source of it on earth. The only way we get elemental hydrogen is through electrolysis and other ways of removing it from molecules containing it. This is a zero-sum game though. Newton's laws say there's no way to gain any energy here, you can only lose it.
Could hydrogen fuel cells be a good battery? Maybe. Lithium-ion battery tech has outpaced it though, and nowadays delivers more power density, efficiency, and safety than hydrogen. Until we come up with a portable fusion generator, I kinda think hydrogen is a dead-end.
Iirc lithium hasn't outpaced in power density, (hydrogen is about 200x more power dense), but batteries are more efficient.
I don’t know anything about them. Where can I learn more?
There are some good in-depth videos on youtube about how they work. The wikipedia page also has some nice information.
I just want to point out that solar powered vehicles are also hydrogen-powered vehicles when you think about it. Most energy sources are.