A) That's called a hydrogen car, and they exist already.

B) Never, the output is water. Then you just use enegy to split the water back into hydrogen and oxygen before burning it back into water. Just add energy from your preferred renewable source.

It sounds like you know how these things work. Will you build one for me?

Eh, just buy one.

We'd never run out because that car is supposedly a perpetual motion machine that converts water to hydrogen and oxygen, then burns it back into water.

Nah, that's expensive, I'll just top off my gas tank with water until it adjusts to its new fuel type instead.

https://en.wikipedia.org/wiki/Toyota_Mirai

Can you please name a make & model? Otherwise afaik Big Oil works really hard to make sure hydrogen powered vehicles never get into the hands of common folk.

The water is split via electrolysis preferably using electricity from renewable sources. The stored hydrogen is then burned in the cars fuel cell using oxygen from the surrounding air. There is nothing magical about it.

Oh sweet. Apparently the nearest hydrogen fueling station near me is 2.8 miles away 😃 I remember around 2004 I was reading about & very much looking forward to hydrogen cars but they didn't exist yet, and I hadn't heard a thing about them since then until now. Why are these not publicized & more popular??? Or have I been living under a rock 😭

Yeah, but this isn't about real hydrogen fuel cell cars. This is about the urban legends about cars that run off water.

Big Oil doesn't need to. Hydrogen cars are almost as inefficient as ice cars. They make no sense.

Maybe for trucks or trains, but even there electric is better

I guess you must be right, since they don't seem to be as popular as the other options. But Wikipedia says they have a 300+ mile range per full tank, so I'm not sure how that could be less efficient than my diesel truck with the same range.

Why are these not publicized & more popular???

Fueling infrastructure is still very scarce and EVs have gotten more popular since then

It's quite the contrary, big oil loves hydrogen because it can be produced by oil/methane and currently is the main way we produce hydrogen (though i think most of it is used in industrial processes and not for propelling vehicles).

This wikipedia article has nice information on current and possible future hydrogen production : https://en.wikipedia.org/wiki/Hydrogen_production

The conversion of water to hydrogen using electricity has about 20% efficiency. There is no advantage over electric vehicles ever since batteries have become compact enough to make battery-powered electric vehicles feasible.

Hydrogen storage takes up insane amounts of space, and converting water to hydrogen is really inefficient. Hydrogen fuelcells are just electric cars, but complicated.

https://m.youtube.com/watch?v=vJjKwSF9gT8

You need to use a ton of energy to produce the hydrogen fuel, so just using an EV is much more efficient.

Their main issue with popularity might be options to actually get the fuel. It like in the very beginning of EV cars, only that you can't even fill it up at home.
And h2 cars don't have the same momentum as EV cars so the chance of that network growing is very slim

Not to forget, that converting it back into water also doesn't produce that much usable power. You end up with an efficiency of maybe 30-40% compared to an EVs 80-90%

That too yea. The only thing better than an ev is the fast refueling, but imo that doesn’t matter as you really should take a longish break after 2-300 miles and at that point, just charge your ev while you take a piss or do some stretching.

Hyundai Nexo

Honda CR-V fuel cell

Toyota Mirai

They're mostly only sold in Japan and California, as that's where there's actually hydrogen fueling infrastructure.

There are other models, they exist, these cars are real.

Also EVs just piggybacked off the existing electrical network. Good luck creating a new worldwide network for hydrogen.

Annual petrol usage by cars: ~1.5 x 10^12 litres.

Amount of water on Earth's surface: 1.386 x 10^21 litres.

Percentage of water used annually: 0.0000001%

Number of years to deplete all water on earth's surface: 1 x 10^9 years, aka 1 billion years.

Minus a few million if we're driving yo momma around.

=)

There is no advantage over electric vehicles

What about batteries' explosive potential & a lifespan shorter than the metal cage it propels?

Hydrogen vehicles would be superior to that.

Well hallelujah I live in California & I want one. Now just need some 🤑

What about batteries' explosive potential

Compared to a literal TANK OF HYDROGEN. Hmmmm.....

a lifespan shorter than the metal cage it propels?

Yeah, there aren't any cars in the junkyard that were scrapped because they threw threw a rod or chewed up their transmission....

Wow. Just, wow.

I mean, you could create your own hydrogen at home. Hydrolysis machines exist, and are sometimes sold as medical devices to create pure oxygen from water. The other half of the output is hydrogen, which would need to be captured in a way that you can put it into your car.

It's an extremely inefficient way to power a car, though. Converting electricity to hydrogen and back to electricity (as most hydrogen fuel cell cars do) is a ton of loss. It's also a bunch of complexity, both mechanical and on the operator.

ETA: fixed typo

I mean, technically nothing is stopping you from making your own gasoline either :D
But yeah you'd be better advised to just put the power in a battery

The urban legend usually just leaves the electrolysis part blurry. They vaguely call it a machine to process or prepare the water, and completely ignore the electricity going in. I.e. hydrogen cars, being "suppressed" by the government.

The urban legend goes back a long time. I first encountered someone telling specifics around 15 years ago, but the vague concept is much older. It's similar to the legend that there's a specially tuned carburator (yeah, that old) that would give you 100mpg, but it was killed by oil companies.

Most hydrogen is made from oil.

You need to use a ton of energy to produce the hydrogen fuel

another ton to store it, and another ton to drive it around.

I mean, you could create your own hydrogen at home.

using electricity. or, just use electricity to power your car.

yeah but I wanna liquid.

What about batteries’ explosive potential

The Hindenburg was battery powered, oh, the humanity.

Guess what element on the periodic table causes batteries to explode? hint: not mentadent.

and it's only $14-$32 a kg!

hydrogen is then burned in the cars fuel cell

fuel cells do not burn hydrogen.

Most hydrogen is made from oil.

In your country. Countries with green energy use renewable sources, so they use water to split water into hydrogen and oxygen and then they can combine hydrogen with oxygen to generate energy and move cars around, all without generating almost no pollution at all.

This guy…. ermm…. waters?

There are some advantages, batteries require more pollution to be created and have a larger environmental impact if not dealt with properly. A hydrogen car has the potential to be 100% clean. That being said I don't think it's that big of an advantage considering some of the difficulties involved in it.

fuel cells do not burn hydrogen.

Why not? Isn't burning a common term for exothermic oxidation? As in 2H2 + O2 -> 2H2O + heat

You're right that some places do that, but it's very rare comparatively.

They really became a lot less of a desirable option as EVs started to get better. EVs have a couple of downsides (weight, charge time) but pretty much everything else about EVs is easier. Hydrogen is a pain in the ass to store in a compressed state, the engines are for more complex than an electric motor, EV charging is easy and obviously far more available at this point, etc.

Because that's not what hydrogen fuel cells do. Yes, you could make a hydrogen ICE car, but that's not a fuel cell car. Fuel cell cars use supplied hydrogen run through a grid to combine with atmospheric oxygen and make electricity and drive electric motors. I had the same misunderstanding for like a decade. Hydrogen is nowhere near energy-dense enough to be feasible as an ICE fuel

https://www.arborsci.com/products/fuel-cell-car-science-kit

Efficiency wasn't what the hydrogen car was trying to solve.

The main goal was to have a carbon-neutral fueled vehicle.

I remember reading about hydrogen fuel cell cars back in 2000, maybe earlier than that. Battery electric vehicles really weren't on the public radar at the time. Essentially the fuel cell would take the place of the battery, storing energy to run an electric motor. We can then use just about any electrical source to separate water into hydrogen and oxygen. Even if the efficiency sucked, flexibilty in sourcing fuel made up for it.

By far most of that water is not fresh water though

Batteries don't really explode, they combust. The metal cage usually outlives its ICE engine as well.

Hydrogen fuel cell vehicles either need extreme insulation to keep the fuel cool, otherwise it has to vent some fuel or risk exloding, or extremely strong pressure vessels in the car to maintain the hydrogen in a liquid form. A metal cylinder constantly expanding and contracting while simutaneously seeing extreme temperature changes is going to wear out much faster than the frame of the vehicle.

The conversion of saline into fresh water via the water cycle will be sufficient to keep the cars running, though maybe not humans. The proof is obvious and left as an exercise to the reader.

Oh yeah. Thanks for reminding me.