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rechosuave t1_iyelwk1 wrote

Reply to comment by BallardRex in The days of the hydrogen car are already over by Sorin61

Why not? Basically an ICE design running on hydrogen. Only change is to fuel delivery. Please remind me of how many EVs are in service? Plenty of room at the table for all types of green designs.

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raygundan t1_iyep6cv wrote

> Why not?

Thermodynamics, mostly. A hydrogen FCEV ends up using about 3x as much energy for the same miles driven as you would if you used the same energy source to power an EV, no matter what that energy source is. A hydrogen ICE is even less efficient than that.

So there's an efficiency gap that you can't ever get over to begin with that will make hydrogen an unattractive option in any niche where an EV is workable-- so for cars, it's probably too late for hydrogen to find a niche.

But there's also a second complication with hydrogen deployment for cars. EVs were a sort of "self-starting" deployment, because you could sell them as second cars to people even before there were public charging stations. It's rare for a home not to have electricity available. Hydrogen, on the other hand, will require filling station infrastructure just to get started. There's no halfway option like there is with EVs. Sell a few EVs, market for chargers increases, build a few chargers, market for EVs increases, repeat. With hydrogen, you have to have the filling stations built before you can sell the cars at all. Saying "the only change is to fuel delivery" is true-- but that's a huge, expensive change that has to happen before you can sell your first hydrogen car.

None of this should be taken as saying hydrogen will have no uses-- just that it's very unlikely at this point to compete in the personal-vehicle niche.

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Enchydrogen t1_iyeqro9 wrote

What are your thoughts on a hydrogen fuel container that can be quickly swapped out for a filled one? I think Toyota is working on this. If this was an option, could charged containers no be delivered or carried on the vehicle for longer trips? Just curious what you think about that concept. Thanks!

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raygundan t1_iyesvha wrote

There's nothing fundamentally wrong with the concept that I can see-- it just has the same chicken/egg issue. That infrastructure doesn't yet exist, but you can't sell hydrogen cars that use swappable hydrogen containers until it does.

It also doesn't help at all with the efficiency issue. Making, compressing, and transporting hydrogen ends up losing a rather substantial fraction of the energy you started with. It really doesn't want to be squeezed into tanks at high pressure-- you'll lose roughly 10% of the energy in your hydrogen just compressing it down to fit in the tank, let alone all the other losses.

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Enchydrogen t1_iyewp7j wrote

Thanks I appreciate the response. The efficiency of creating it does seem to be an issue but can we look past that if the "price is right" and the advantages of using a green energy are apparent? For example, lets say I could drill down deep enough where I had essentially infinite geothermal energy producing hydrogen and then export it from there, would the efficiency issue even come in to play at that point as long as the transportation costs were low enough to sustain business?

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raygundan t1_iyeyggz wrote

> For example, lets say I could drill down deep enough where I had essentially infinite geothermal energy producing hydrogen and then export it from there, would the efficiency issue even come in to play at that point as long as the transportation costs were low enough to sustain business?

All sorts of things start to make sense once you have "essentially infinite energy" from a clean source. When you get to that point, you can even do things like synthesize gasoline from scratch, burn it in hilariously inefficient 1940s race cars built from WWII aircraft engines, and then run a carbon capture system to undo the damage.

But we're not there yet. The efficiency issue still matters because our grid still gets the majority of its energy from dirty sources, so when you look at two options to do a particular job (passenger transport in this case) and one of them needs 3x the energy per mile driven... it's a hard sell. Ask me again when we're on 100% clean energy with some surplus to spare, and it may suddenly make sense despite the huge efficiency hit if somebody can build an FCEV substantially cheaper than an EV.

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Enchydrogen t1_iyf03a1 wrote

Efficiency only matters in that case when you are extracting the energy to create the hydrogen from the grid and in my scenario that is not the case. Also, I think it worth mentioning that energy transportation plays a part here. We have never really had an energy medium that can be created anywhere where there is excess energy and transported to where it is needed. I totally get the reinforcement of the inefficiency point but I feel as though if it can be produced in mass, somewhere we have excess energy that cant be power lined to the grid, and transported, it should be used just for the shear abundance of it and the advantages of carbon reduction regardless of efficiency of creation. Let alone the benefit of reliance on foreign powers. Just some thoughts, but I appreciate your feedback.

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raygundan t1_iyf0zwp wrote

> Efficiency only matters in that case when you are extracting the energy to create the hydrogen from the grid and in my scenario that is not the case.

Sorta. What you've proposed might not be grid-connected-- but connecting your hypothetical geothermal power plant to the grid is still an option instead of using it to make hydrogen.

But broadly speaking, I'm with you-- if you have excess clean energy that for some combination of reasons cannot be utilized in any other more-efficient way than by shipping it out as hydrogen, go for it!

If somebody suggests to me "what if I build a power plant, don't connect it to the grid, and use that to make hydrogen" my first question is always going to be "what if we connected it to the grid instead?"

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Enchydrogen t1_iyf3njl wrote

Totally get that point and the only thing I can think of is (and I'm just spitballing here) something far enough away that you may lose power using traditional power lines to transfer to where its needed. What if the deserts are one of the most unused and underappreciated natural resources on the planet? Essentially becoming "oil fields" with how much they could output in solar hydrogen. No other way to get that energy from the Sahara Desert to my house/truck/airplane to transport it via H2 that I can see. Its a fantasy today, yes but I hope those places in the world that are viewed as desolate and useless can be looked at with new eyes. A desert could be a gold mine.

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raygundan t1_iyf791f wrote

> far enough away that you may lose power using traditional power lines to transfer to where its needed.

Certainly possible, but even long-range power transmission has fairly low loss compared to something like producing and shipping hydrogen.

> No other way to get that energy from the Sahara Desert to my house/truck/airplane to transport it via H2 that I can see.

You're basically saying "what if we build in this difficult area" but the difficulty of building the plant and shipping infrastructure there aren't likely to be radically different than the difficulty of connecting it to the grid. One option is going to require a pipeline, road, or rail all the way to this out-of-the-way facility-- and one option is going to require a power line. You're going to have to build "a connection" one way or the other, and it seems like it would take pretty narrow conditions to make a road viable but a power line not.

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Enchydrogen t1_iyf95lo wrote

Copy that. Thanks for the insight, man. I am hopeful but I know hydrogen has a long way to go to prove itself. Hopefully it can find a way to solve some of the worlds problems. Cheers, brother and have a good night.

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raygundan t1_iyf9g7i wrote

> Hopefully it can find a way to solve some of the worlds problems.

Agreed on that! It's one more option in the toolkit, and just because some of the more obvious niches (cars, for example) are probably better done other ways doesn't mean we won't find good ways to put it to work.

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IvorTheEngine t1_iyf0f3d wrote

The problem there is the same reason swappable batteries for EVs never caught on. You'd need all the vehicle manufacturers to agree on a design, and the filling station networks would have to agree to accept each other's old bottles. And that has to still work if you drive from the US into Mexico, or Europe to Asia.

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