this post was submitted on 05 Jul 2024
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Add a hydrogen generator and all you need is water and electricity to make the hydrogen. You don't even have to transport it.
I'd much rather transport a bottle of hydrogen to a cookout than an electrolyzer. What if a power outlet isn't available?
And I’d rather transport a cheap and widely available propane tank instead of an ultra high pressure hydrogen canister that can only be refilled at 3 places in the entire state.
Yes, but imagine a world where propane and other fossil fuels are no longer available. You're going to lug a big battery around for an electric grill instead?
For what it's worth hydrogen stations currently dispense at 10,000psi, which is considered "medium" pressure in the field. "Ultra high" pressure is considered an order of magnitude greater.
Yeah batteries would probably work. A large battery bank can have 1kwh of capacity, and induction stoves are about 1.5kw. Which means you could run a stove for about 40min. You could bring more for longer. I'm sure by the time you can't get propane, batteries will have gotten much better too.
That's a lot of future e-waste to lug around just for cooking.
As opposed to a lot of super compressed gas to haul around? I didn't think this super niche use case justifies a whole different technology.
Hydrogen is very difficult to bottle. It tends to just slip out of anything you put it in because of how small the atoms are.
And also incredibly low density. So your bottle would likely be on a trailer.
If hydrogen is so difficult to bottle then how are there self-serve refuelling stations in operation?
Yes, there is a volumetric penalty, but it's not that bad. At 10,000psi a 1 gallon hydrogen bottle has roughly the same energy as a 1lb bottle of liquid propane for camping.
An industrial machine designed to handle 10,000 psi gas is a little different from a tank you’d take to a BBQ.
A fuel station will also get resupplied regularly, so any small leaks are no big deal, as there will be a shipment of fresh fuel coming in a regular schedule. Your BBQ tank of hydrogen likely will need to be refilled regularly even if you don’t use it, as any valve that would be cheap enough to mass produce is not going to be able to keep hydrogen in for months while it sits in the garage.
Then there’s also the fact that most uses for gaseous hydrogen require the above 10,000 psi storage pressure. This allows a useful amount of hydrogen to be stored in a non-comically large container. 2 problems I see with this:
1.) a 10,000 psi container is fucking terrifying. If that things bangs into something and ruptures, it going to send shrapnel through a house.
2.) a propane like tank can be opened to the Atmosphere and does not have a regulator built into the tank because most people don’t know how to actually use a regulator. So a 10,000 psi tank with just a hand valve between the user and a jet of gas that can send the tank into the stratosphere does not sound like something that should be available at your local hardware store.
If the tank were made of a carbon fiber composite it would make it a little less scary. CF's high strength and brittle failure mode mean that the tank would "open up" on a seam when ruptured, but would stay mostly intact. Additionally CF's low density would mean that any small pieces of shrapnel that were created would have limited penetrating power and range.
Still I'm not sure I would want to stand next to it. At 10,000 PSI a small hole (or opened valve) in such a tank would produce a gas stream with enough energy to seriously injure or kill you (leaks in 4000 PSI steam lines can cut your flesh and create gas pockets inside you). The entire tank letting go all at once would surely create a shockwave that would obliterate you.
If these are serious concerns for you, I'm sure you will always be able to find plug in electric grills on the market.
I don’t think you really grasp how much pressure 10,000 psi is.
A typical car tire is like 35 psi
A propane tank for a grill is like 200 psi.
Have you ever seen a car tire burst? Or a propane tank? Big booms, they can easily hurt or kill people already.
A hydrogen tank would be 50 times more pressure than a regular tank of fuel, and 300 times more pressure than a tire. If those burst, people will die, and have their bits spread around the neighborhood.
Unfired pressure vessels are already pretty common common in industrial, commercial, healthcare, transport, and recreational settings. I am comfortable with continuing to trust the engineers as the portion of these vessels that contain hydrogen increases.