Submitted by Hypx t3_10mdti7 in Futurology
ttystikk t1_j62pqwm wrote
Reply to comment by Angry_Washing_Bear in Cryo-compressed hydrogen, the best solution for storage and refueling stations? by Hypx
I've seen explosion events in propane powered cars in video, and those were just a barbeque tank or so in size.
There are a lot of reasons why hydrogen isn't a good transportation fuel and we can throw this one on the pile.
Angry_Washing_Bear t1_j62qal8 wrote
I can see its use in shipping since any accident on a ship, while catastrophic, is at least somewhat isolated and contained as opposed to vehicles in dense traffic, parking garages, near residential homes etc.
ttystikk t1_j62r6ry wrote
Electric cars are just better and they are still improving rapidly.
IGetNakedAtParties t1_j62x1dp wrote
That's kind of the missed point when comparisons are made, batteries are advancing according to their own (lower) version of Moore's law, energy density has tripled over the last decade. And more importantly the prices are obliging Wright's Law, coming down in relation to production volume. The physical limits of known technology are still 3x away.
Hydrogen is limited by physics already, with only small improvements in efficiency available.
Hypx OP t1_j6360qt wrote
Except that hydrogen just gained 80% more energy density right now. You should read the article.
In fact, it has already exceeded the theoretical limits of any conventional battery chemistry. So in some sense the war is already over on this subject.
IGetNakedAtParties t1_j63arkg wrote
In the case of cars and road haulage it's not necessary as current energy density of batteries is already practically sufficient. The total system energy efficiency of batteries is significantly better they hydrogen can ever be, and higher compression actually makes this worse source
This technology does have practical applications for ocean shipping, and possibly flights down the line (as the article points out) but often the focus is on personal vehicles as the article mainly focuses on. And this is my main criticism: most of the narrative around hydrogen is used to support the argument that "we should keep using petroleum for now as hydrogen is just around the corner" whilst ignoring the fact that BEV is already better than gas from a total cost of ownership perspective.
I can't claim that this article is connected with the oil industry or traditional auto, but as BMW have their majority of their profits from ICE and the publishing house is based in Detroit I can't help but question the intention of the publicity, independent of the value of the technology.
Basically, all research like this is valuable, but the narrative is often used against BEVs which I am suspicious and critical of.
Hypx OP t1_j63b76d wrote
Then why mention energy density if you ultimately don't think it matters? It will mean much lighter cars and more range. You should be suspicious of those who don't want those options.
IGetNakedAtParties t1_j63cm63 wrote
As I said, "more importantly costs are falling under Wright's Law" meaning energy density isn't much of a concern, but even if you believe it to be important it is still improving in BEVs.
The article is exclusively about energy density and doesn't mention the financial or energy costs of the cryogenics, energy density is important for practicality but cost is what will drive adoption.
Lighter and/or better range BEVs at better prices are inevitable: hydrogen lost this competition. My criticism is against the article's narrative that hydrogen is "just around the corner" for personal cars and road haulage, it cannot compete on price based on the physics involved.
Don't get me wrong, I'm happy that the technology is improving, hydrogen will likely have it's place in ocean shipping because of technology like this increasing energy density to practical levels. I'm not against hydrogen, I'm against hydrogen (stories) being used against BEVs by oil and ICE companies.
Hypx OP t1_j63csvv wrote
Cost would be a different subject. No one brought that up until you did just now.
Also, you should expect cost to come down for any technology. Especially one that is radically superior to what came before it.
IGetNakedAtParties t1_j63dm81 wrote
For sure costs will decline for both, but the physics of the supply chain will always give a cost benefit to batteries where they are practical. And we should not be waiting for anything as TCO of BEVs is already on par to ICE.
It's that which makes me critical of all "hydrogen cars" articles, I've yet to read one without a connection to the oil or ICE industry.
Hypx OP t1_j63f2ho wrote
Even after just now, after a 80% increase in energy density? You do realize that at this density, a few tanks the size of scuba tanks will easily get you 300 miles of range in a hydrogen car? Volume wise, it's basically the same as a gasoline tank in a conventional car. So pretty vast amounts of cost is coming out of that hydrogen car.
And yet you're so certain that this can't be cheaper...
IGetNakedAtParties t1_j63fcu1 wrote
Unless cryogenically liquifying hydrogen has a negative energy cost, yes. The physics doesn't make sense.
Hypx OP t1_j63fugu wrote
Are the batteries in your EV free in this example? We're talking about a hypothetical hydrogen car that is effectively identical to a conventional car in basic material needs.
Also, this is not liquid hydrogen. You should read the article.
IGetNakedAtParties t1_j63plkb wrote
OK, I'm interested in making this calculation, I'm happy to have my assumptions challenged.
As per my link, the efficiency of BEVs from source to wheel is 76%, the current same for hydrogen is 30%. This technology will likely make this worse for H2 in exchange for better practical applications, range, weight, etc.
If you want to compare a hypothetical H2 car against a real world BEV lets compare a Tesla Model Y against the best case H2.
Assumptions:
12 year vehicle lifetime
14 000 miles per year
0.0456 $ per mile (typical home charging)
0.1155 $ per mile (assuming the above relationship, this accounts for inflation in the comparison)
These numbers give us the cost of energy difference at $11 743 in favour of the BEV. Given that a replacement MY batters is $15 000 you are correct that the H2 is better economy than the BEV, however the BEV exists now, with a charging infrastructure, but the H2 vehicle does not. Also whilst H2 costs aren't likely to change much with economy of scale, this definitely isn't true of battery technology.
Basically my previous points stand, H2 is going to be important for some uses, but there is a danger that stories about it give the illusion that we don't need to stop using ICE now and switch to BEVs for personal vehicles for both environmental and economic reasons.
One can be pro BEV and pro H2 at the same time.
Hypx OP t1_j65d048 wrote
But no talked about what is better right now.
You're just making a big fuss while basically accepting my point.
IGetNakedAtParties t1_j65e6c0 wrote
Please don't manipulate what I say for your gain.
Hypx OP t1_j65efnj wrote
This is futurology. You're just being a jerk while missing the point.
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