-
Want to remove ads? Register an account and login to see fewer ads, and become a Supporting Member to remove almost all ads.
He did have tracer rounds. I think he planned on a spectacular boom, but probably changed his mind.
Probably not even then. Aviation fuel isn't that easily ignited.
Hydrogen/air mixtures on the other hand are know to self-ignite, and an invisible spark is enough to set it off. It's also flammable in concentrations of 4-75% in air, and explosive in concentrations of 18.3-59%. Basically any significant hydrogen release will mix with air and end up in the 4-75% zone, and then it's almost certain it will ignite. Hydrogen's one redeeming feature is it's buoyancy. It will rise into the air relatively fast. So, as long as you keep compressed hydrogen in smaller tanks with safety valves and stuff, and have a sufficient safety zone around a filling station, filling can be done relatively safely.
I don't think hydrogen tankers carrying hundreds of kilograms of compressed hydrogen are at all a smart idea, though. Hydrogen transportation should be done either in liquid form, through the grid as electricity (water + electrolyzers), or in small diameter pipelines.
Worst case, a hydrogen tanker would be used for terrorism. You could just roll into any tunnel or parking garage, and release the hydrogen. It would disperse in the structure, and would at some point ignite. Then you end up with this, only thousands of times bigger (I'd estimate this at about 100 grams):
That's true for private miles, if you have the ability to charge at home or it's commercial travel that's either within range or not time-sensitive.
Unfortunately, at the moment that doesn't apply to the majority of the market. Costs need to fall to grow the market, to expand access to home charging. It's getting there, but it isn't there yet.
david_42
Member
An interesting tidbit from the commercial sector:
Proterra | Battery Charging Systems for Electric Buses
"Specially-designed batteries for the Catalyst FC can charge in 5-13 minutes" That's for a 126 KWh battery
SageBrush
REJECT Fascism
Interesting stuff. Up to 73 EV buses might go into service in the Seattle area by 2020 if things work out. The charging rate is not clear to me, but the max rate appears to be use of a combination of ports -- perhaps both on the side and top of the bus. From their spec sheet:
FutureShock
Best Coast Denizen
With respect, I'm not sure it's about that anymore.
I mean, yes, once upon a time, battery technology and fuel-cell technology leap-frogged each other to see who could be the leading (and at the time, always irrelevant) 'successor to ICE'. But, we've now finally gotten to the point where replacing ICE can actually be a reality over the next 20 years or so. And, as it turns out, battery EVs look like they're the ones that are going get to to do it.
'Problems remain', as they say, but they're being resolved. Next-gen Tesla and VW superchargers should 'fill up' even longer-range EVs in 15 minutes or less. The cost of batteries continues to fall... many analysts predict full EV cost-parity with ICE vehicles by 2025 as a result. After that, EVs actually become cheaper, due to their greater simplicity/fewer parts.
So, whatever time-window FCVs have left to jump in and 'fight EVs for the future' is closing fast. Which may be part of why FCVs are having a hard time attracting investment (beyond their already existent core believers), and building any momentum.
So if it's not really about the battery tech vs fuel-cell tech battle anymore (since EVs seem to have that won or mostly won at the right time in history to replace ICEs), what IS it about? I'd say it's more about Toyota's now-disrupted business plan for the next 30 years, and their fervent desire to salvage it.
If you read the company's various statements over the years (and I think they even have official 'roadmaps' laid out too, all the way to 2050), Toyota has fervently believed for many years now that the future in automotive transport was going to be hybrids (which they have a technical/expertise advantage in) for the short-to-medium term, and FCVs (which they have a technical/expertise advantage in) for the long-term.
IOW, they 'saw the future', and then wisely skated to where the puck was going to be. Only, the puck never showed up. EVs (and the market) stole it. Who could've seen Tesla coming? Who could've seen handheld gadgets becoming so popular that the thing that powered them (Li-ion batteries) would attract so much investment and would improve so much?
Further distorting things, the Japanese government is putting a great many incentives behind FCVs. So, instead of doing what most businesses would do when the market and circumstances throw you a curve ball, which is to belatedly change and adapt, Toyota is doubly-incentivized to continue to fight for a lost cause, i.e. FCVs in passenger cars and Toyota's grand plan to dominate automotive tech for the next 30 years.
They are still hedging their bets by now finally getting into EVs in a significant way, but you can tell their heart really isn't in it yet. They have a lot of top execs with a history of saying disparaging things about EVs. Some of those guys probably have to go before Toyota does a true about-face.
So, we'll see. But I think for passenger cars, the bell has already tolled for FCVs. Large trucks and busses may possibly be a different story (hydrogen FCVs lack of infrastructure hurts it less there)... but even there, it's likely that batteries will eventually be cheap and fast-charging enough to take the market away from fuel cell-tech.
Mass energy storage (for utilities using renewables) will be yet another market, and once a utility invests in an expensive major resource/capability such as storage, it isn't exactly going to just rip it out and replace it with alternate tech, it's going to continue to use what it built until it wears out and/or becomes so very technically inferior that it makes obvious financial sense to get rid of it. So if fuel cell tech gets a foothold in there, it's going to be in there for a long while to come.
So, hydrogen fuel cells are not dead yet. I doubt very much they'll win or even make a significant dent in the global passenger car market outside of Japan (no matter how much Toyota gnashes its teeth over that), but, there are other big areas for them to compete in.
.
Last edited:
The limit isn't chargers, it's battery chemistry. What battery chemistry allows 10-80% in 15mins without a huge hit to energy density or cost?
mspohr
Well-Known Member
OMG! You're right! The people designing these fast chargers haven't considered the batteries at all!
Quick, tell them they are making a big mistake and that they need to look at the batteries too!
Isn't the fundamental issue with Fuel Cells vs Batteries one of efficiency? Given that the "fuel" isn't one (it needs to be manufactured), even after all the charging and storage issues are solved, a FC-based system is inherently less efficient on a well-to-wheels (or whatever) basis than a direct-to-battery one. Laws of Thermodynamics. That may not matter if some day we become flush with free excess renewable power, except that the excess energy has to go somewhere, and it all ends up as heat.
And fundamentally, excess heat is what we are trying to eliminate, and free excess renewable power is not likely to ever happen. Right?
And fundamentally, excess heat is what we are trying to eliminate, and free excess renewable power is not likely to ever happen. Right?
If the issue were efficiency, the majority of cars sold would be hybrids.
The issues are cost and utility. PEV cost and utility have improved quickly, but they aren't yet good enough to take over the market.
Sure, but I'm looking farther down the line. Some are claiming that the issues with costs and technical challenges with H2 generation, distribution, and storage, etc. can be solved. Others talk about battery capacity and charging rates. Some day both will be right. I'm just saying that it doesn't matter. Even when that happens and all those issues go away, the fundamental laws-of-physics difference in efficiency remains, and that's the killer for FCs. We will never have so much free, clean, renewable energy that we can waste half of it on an inefficient system.
There absolutely are applications for fuel cells where a battery just won't do. But I don't count automotive vehicles among them, and therefore argue that investment in putting them there is being misspent.
mspohr
Well-Known Member
Sorry for the snark but my question (which you missed) is do you really think that people would design a high capacity charger without considering battery capacity?
robertvg
Extremely Well-Known Member
I doubt it. How many fuel cell trucks and buses do we know or have been announced ?
On the other side; I see Daimler, VW showing or announcing new e-trucks, and full electric buses are bought by the hundreds.
Besides costs, infrastructure and inefficiency I wonder if the smaller battery packs of f-trucks are able anyway to deliver the power required by the vehicles. Batteries are the bottleneck there; you need larger packs to get the power.
ElecFan
Member
stopcrazypp
Well-Known Member
Styling and performance matters too, and Tesla has that in spades. The hydrogen cars released so far don't. The problem with HFCVs is that the cost scales by power, which is why the cars released are relatively gutless.
350kw charging for buses and semitrucks doesn't benefit owners of current technology batteries in cars, and I haven't heard of any major breakthroughs that allow 15 min charging without sacrificing energy density or life a I have no doubt it will improve, but going from the current charge times to 15minutes to 80% is going to take years, if not decades, if it is even possible.
Similar threads
