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Why did we abandon hydrogen cars so quickly?

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I wonder if it would be feasible to put an electrolysis rig hooked up to a fuel cell in a hydrogen fuel cell car. This would give it the "home charging" aspect of a battery vehicle but could be filled at a station with hydrogen for faster "recharge".

I get that it wouldn't be that efficient due to the small scale, but it would be cheaper than transporting/storing hydrogen in electricity costs.
 
Using tap water?
 
Probably have to be distilled; lots of contaminants in tap water. Possibly DI water would work; non-ionic bonds are pretty immune to electrolysis IIRC.

Can't imagine chlorides or fluorides doing well in an electrolysis cell, both of which are found in relative abundance in tap water.
 
Indeed, hydrogen can be green. Depends how it's produced, at the moment a lot of renewable energy is wasted off peak because it can't be stored.

Then there's natural hydrogen which you don't need energy to produce, just need to extract it.

Yes, hydrogen can be green, that is not the problem. The problem is that even with free electricity hydrogen production and storage is too expensive. This is due somewhat to efficiency, but also due to the nature of electrolysis, to be efficient it needs a constant supply of electricity - not what you get for free.

Natural hydrogen is a possibility, but none has been found that can be used commercially. Even if it exists in quantity, it may not be feasible to clean it enough to use in fuel cells.
 
I wonder if it would be feasible to put an electrolysis rig hooked up to a fuel cell in a hydrogen fuel cell car. This would give it the "home charging" aspect of a battery vehicle but could be filled at a station with hydrogen for faster "recharge".

I get that it wouldn't be that efficient due to the small scale, but it would be cheaper than transporting/storing hydrogen in electricity costs.
It would not work, they way you want it...as it would function only to lower the mileage of the H2 vehicle! :cool:
 
Effectiveness of water to H2 (& O2) generation is less then 100%...sthg like 50~60%.

So any power generated from fuel-cell, will only make ~1/2 of H2...& fuel-cell itself is efficient around ~ 2/3.

So adding water electrolysis, without even talking about losses in the systems of transfer of electricity between fuel-cell & electrolysis generator, is about ~1/3 as efficient...or you would downgrade the efficiency of a fuel-cell in Mirai, down to Otto engines! ;)

--
Now, lets look on Mirai fuel-cell....which can generate 128kW of power.
Its motor has about 136kW of power...so in order to keep it up running all the time, Mirai uses 1,2kWh of batteries.
So any power you draw from fuel-cell to electrolysis generator would not only starve the motor & batteries, but also reduce the mileage on Mirai! :cool:

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Life would be great, if there would be violation from 1st Law of Thermodynamics.
But then again, then we would not be in this World as it is...in that Universe a simple things like Friction would not exist! ;)
 
No, I meant to carry an electrolysis rig to recharge the hydrogen storage by plugging in your car. This would simplify the lack of investment in hydrogen infrastructure, similar to Teslas before there were a lot of charging stations.
 
The problem is that even with free electricity
No such thing as free Electricity somewhere in the life span of whatever way you want to create it there's a cost whether that's in it's creation running or disposal/decommissioning there's an environmental cost at some point
 
No, I meant to carry an electrolysis rig to recharge the hydrogen storage by plugging in your car. This would simplify the lack of investment in hydrogen infrastructure, similar to Teslas before there were a lot of charging stations.
Those stations are subsidized from Japan, UK, EU & USA - locally. So the infrastructure is going to be made.

It is why I said that Mirai is like Prius 1gen...not so much charging stations around! ;) (OK, Prius 1gen was not PHEV...but still an early technology)
 
I wonder if it would be feasible to put an electrolysis rig hooked up to a fuel cell in a hydrogen fuel cell car. This would give it the "home charging" aspect of a battery vehicle but could be filled at a station with hydrogen for faster "recharge".

I get that it wouldn't be that efficient due to the small scale, but it would be cheaper than transporting/storing hydrogen in electricity costs.
No, I meant to carry an electrolysis rig to recharge the hydrogen storage by plugging in your car. This would simplify the lack of investment in hydrogen infrastructure, similar to Teslas before there were a lot of charging stations.
Which brings up again the problem of compressing hydrogen, and fitting a compressor inside the car, with all the weight, expense, and inefficiency. Could be hard to make it work.

Storing the hydrogen in metal hydride would essentially be reinventing NiMH battery and without a much better energy density.

If you modify the chemistry so the hydrogen won't evolve from the solution...then it might work, but then it would also be the same thing as a rechargeable flow battery.
 
Which brings up again the problem of compressing hydrogen, and fitting a compressor inside the car, with all the weight, expense, and inefficiency. Could be hard to make it work.
IIRC a lot of small-scale electrolysis rigs use high pressure water and let the hydrogen compress itself. You should only need a positive displacement pump to add water to the system.
 
Thanks for the Hyundai link.

Here in CA we have both BEV and FCV at airports as experiments. The cost difference is about 3-5 times more with hydrogen. BEVs can use solar installed at the airport fairly efficiently, FCVs have the electricity>H2>storage>electricity losses. Both systems are attempting to only use power from solar so BEVs charge daily, electrolysis plant gets heat cycled daily.
 
IIRC a lot of small-scale electrolysis rigs use high pressure water and let the hydrogen compress itself. You should only need a positive displacement pump to add water to the system.
While compressing a liquid with a pump is much easier than compressing a gas like hydrogen, there is still the problem with pressure, sufficient pressure to put most hydraulic systems to shame, and the problem of putting such a system on a mobile platform in traffic; Diesel fuel system is similarly high pressure, but the volume is small, and there is no gas phase and not nearly as much stored potential energy.

I sure hope someone would find a workable way out of this.
 
While compressing a liquid with a pump is much easier than compressing a gas like hydrogen, there is still the problem with pressure, sufficient pressure to put most hydraulic systems to shame, and the problem of putting such a system on a mobile platform in traffic; Diesel fuel system is similarly high pressure, but the volume is small, and there is no gas phase and not nearly as much stored potential energy.

I sure hope someone would find a workable way out of this.

Possibly, but I am not sure how bad it would be with a car company actually applying engineering to it. After all, if a quarantined Russian can do that in his garage...
 

Possibly, but I am not sure how bad it would be with a car company actually applying engineering to it. After all, if a quarantined Russian can do that in his garage...
That's not the same thing at all.

(Near) Atmospheric pressure hydrogen is essentially useless for a vehicle. For a hydrogen vehicle, the thing needed is a way to consume energy when it is cheap or convenient to produce hydrogen (the thing your video covers), and then a way to compress the hydrogen to use later, at a place where another energy source is not available, in a useful quantity. The compression requires 10,000 to 20,000 PSI to have a reasonable and worthwhile energy density to justify the time, expense, and inefficient conversion process. Those plastic hoses are not "high" pressure to any degree necessary.

The video you presented has no meaningful compression and is instead just a way to waste electricity by turning it into some useful energy plus around 40+% wasted heat. It doesn't store it in any meaningful quantity, and therefore provides no benefit to outweigh its inefficient drawbacks. If you have the power there, it is better to just use the power there in a more efficient way. The only time an inefficient process should be used is when it provides some other benefit, or as a toy.

Please see video I posted a couple of pages ago. He demonstrated why it would be better to hook that motorcycle battery directly up to an electric motor instead of draining 40+% of the battery for no useful purpose. The range is less after doing all this energy conversion, and the weight is greater.



The thing to remember is that the hydrogen is being used as an energy storage medium. When you "produce" hydrogen, you don't create energy, you just convert existing energy into less energy of a different form. The battery example in your bike video is a very simple one to consider critically, because it keeps all the energy inputs and outputs in one system. Ignore the appropriateness of the unit of energy, it doesn't matter: Let's say you have 10,000 joules of energy stored in a battery which was obtained from some other source. You then use that 10,000 joules to create 8,000 joules of hydrogen. Then you "burn" that 8,000 joules of hydrogen either in a fuel cell or in a combustion engine, and create 2,000 to 4,800 joules of motion. Again, the units are wrong, but you can convert them, if you care. The end result is the same. You wasted a lot of battery in order to do a little work. And those numbers are best-case. In reality, you have to compress hydrogen to make a product that has any practical use, and that makes the efficiency numbers even worse. It is much better to just hook that battery up to an electric motor, since that battery is already mobile. If the energy source isn't mobile, then hydrogen can be an option to store energy, but only in some circumstances when the scale is large enough to make it worthwhile and other options don't exist for some reason. Currently there are almost always better options. At the moment, the only time hydrogen seems to make sense is when it is for political or environmental reasons. Or for some scam investor reason. If batteries are too bad politically or ecologically, and the hydrogen production's energy source is better than the fossil fuel alternative, good! But that is pretty much never the case at the moment. Only 5% of hydrogen is produced by green energy, and that completely kills it as an option. Everything else is just an additional reason why hydrogen is a bad option.

Fact: you do less environmental damage by just burning gas in your car, instead of burning hydrogen in your car. That's why hydrogen vehicles are absurd at the moment. Using hydrogen in your car, you burn more fossil fuel for the consumer to dream that they are reducing fossil fuel reliance.
 
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Mirai tank is 700bar, so 10kpsi. Not too hard to find a water pump that will do that.

I get that the video.linoed above is not the best way to do it. For example, it produces and stores hydroxygen gas and not pure hydrogen - I sure as hell wouldn't go anywhere near it.

I can't figure out what pressure he got out of it, but he stored enough HHO gas to run a 5 foot flame for ~30 seconds in a tank about the size of a fist in a different project. Not what I would call low pressure, myself, although I doubt it would be anywhere near 700bar.

The thing is, electrolysis can achieve those pressure and more in a closed system. You just have to find a way to vent or store the oxygen separately, or I ain't touching it.

Sure, it's less efficient than pure electric on a wall charger, but it can charge a lot faster for road tripping. Thing is, there aren't a lot of hydrogen stations around, so it isn't really practical to have a hydrogen car without some way to generate hydrogen independently.

Of course, PHEV would be another way to mitigate needing hydrogen for commuting but keeping rapid travel beyond charge range. Probably more practical in general.
 
A pressure washer is maybe 4000 psi, so I guess you are right.
 
- I am not sure that a pump designed for liquid will be able to effectively pump the smallest molecule.
- High pressure electrolysis pressure maxes out at only 29% of the minimum pressure often considered required for utility, viability, or effectiveness.
- Ultra high pressure electrolysis seems to be an option, but it appears to be rare, big in scale, and expensive. Probably capable pumps compete at this level. Both appear to have efficiency problems.
- I don't think that someone just forgot to try a pressure washer or liquid pump.
- All of this remains just a theoretical discussion when the root of the problem is that burning gas in your car is still currently more effective, cheaper, and better for the environment. If we want hydrogen to be an environmentally friendly "fuel", we need an environmentally friendly energy source to produce the hydrogen. Hydrogen is not an energy source, as it is too reactive to exist in a usable form. It is being used only as a method of energy storage. An environmentally friendly energy source remains the challenge that hydrogen forgets to solve.
 
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Question

When one compresses a gas, it gets hot, so how much heat is lost when compressing hydrogen?
 
Question

When one compresses a gas, it gets hot, so how much heat is lost when compressing hydrogen?
I don't remember the formula for that one. I suspect it is not significant; there should be enough waste heat in even an electric motor (IIRC a fuel cell produces heat too) to heat the hydrogen back up upon decompression.
- I am not sure that a pump designed for liquid will be able to effectively pump the smallest molecule.
- High pressure electrolysis pressure maxes out at only 29% of the minimum pressure often considered required for utility, viability, or effectiveness.
- Ultra high pressure electrolysis seems to be an option, but it appears to be rare, big in scale, and expensive. Probably capable pumps compete at this level. Both appear to have efficiency problems.
- I don't think that someone just forgot to try a pressure washer or liquid pump.
I don't know enough about industrial electrolysis to dispute this. Do you have any links for me to learn more?
 
Not to rain on the parade, but I think we have established hydrogen at home will not work. Permits for the creation and storage will be near impossible and the system is very expensive. All the while we have BEVs that are more efficient and just plug in.
 
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