General > General Technical Chat
EV-based road transportation is not viable
Ice-Tea:
--- Quote from: nctnico on February 21, 2023, 12:19:23 pm ---
--- Quote from: tggzzz on February 21, 2023, 11:20:30 am ---
--- Quote from: Ice-Tea on February 21, 2023, 09:52:28 am ---Flamability range:
Activation energy:
--- End quote ---
Useful comparisons. Thanks.
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It is not at all. Just more fear mongering. Hydrogen is very light so it will move up quickly (out of the building) where gasoline, natural gas and LPG vapours will sink forming a blanket. So the chance you'll actually get an explosion or fire from hydrogen is far lower. Putting things further into perspective: you'll need a fairly small space to achieve a flammable hydrogen mixture. With 5kg (typical for a hydrogen car) of hydrogen you'll need less than 6 parking spaces worth of air volume. All in all a hydrogen leak from a car is far less of a problem compared to a car leaking CNG, LPG or gasoline.
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Natural gas is also lighter than air.
That said, as we're exchanging stories: I did a training about gas bunkering etc. The teacher stated, quite bluntly, that of the many types of gas carriers/vessels/tanks he had been involved with only hydrogen stuff scared him.
But sure. Just dismiss it as "fear mongering".
nctnico:
A cargo ship filled with hydrogen is something totally different compared to a car or a train carrying a relatively small amount as fuel. If you go onto an oil platform you'll be subjected to all kinds of safety measures & training requirements while you are basically handling the same stuff at a gas station.
tom66:
At least one hydrogen filling plant has exploded in the past:
https://driving.ca/auto-news/news/hyundai-toyota-pause-fuel-cell-sales-over-explosion-in-norway
Though certainly not enough data to draw a conclusion over safety with this one event.
Two were injured when "their airbags went off" - I guess it could have triggered the crash sensor for a car but a bit odd as I had thought those only work when the vehicle is in motion.
tggzzz:
--- Quote from: tom66 on February 21, 2023, 01:12:02 pm ---At least one hydrogen filling plant has exploded in the past:
https://driving.ca/auto-news/news/hyundai-toyota-pause-fuel-cell-sales-over-explosion-in-norway
Though certainly not enough data to draw a conclusion over safety with this one event.
Two were injured when "their airbags went off" - I guess it could have triggered the crash sensor for a car but a bit odd as I had thought those only work when the vehicle is in motion.
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Other guesses:
* you need airbags to activate if you are stationary and someone hits you at high speed
* "acceleration" setting off a gasbag can have the sensor embedded in the gasbag module, whereas "velocity" requires an external sensor and hence extra failure modesI imagine the latter's failure modes involved with emergency detonators is more defining.
tom66:
Indeed, side impact detection on cars is usually via an air pressure sensor in the door, rather than an accelerometer. These could have been cars driving past the plant at the time, too, I realise it's not clear if they were actually stationary or not.
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