Oils4AsphaultOnly wrote: GRA wrote:
And I've certainly never claimed that H2 is inherently safe, or that high compression storage is the safest method; indeed, I've said (in the H2 and FCEVs topic, and possibly others) that the ultimate goal for FCEVs is low pressure storage through adsorption or nanotubes, if either can be made to work economically, for both safety and design reasons, as LP storage allows use of tanks shaped to fit the car (especially in a skateboard configuration), rather than cylindrical ones for strength. Here's one such post from 2013, but you can find many others from me if you search for "adsorption nano-tube" with me as the poster: https://www.mynissanleaf.com/viewtopic.php?f=10&t=14638&p=332079&hilit=adsoprtion+nano+tube#p332079
I wasn't aware that you felt this negatively about H2 storage, considering how vehemently you've been defending FCEV's. It's just such a contradictory position to hold, since all current FCEV's have relied on high-pressure H2 tanks.
GRA wrote:I note, however, that the front seat occupants in your video were able to exit the vehicle, apparently uninjured (hard to say for sure; IDK if anyone was in the back, where injuries would be more likely.
They survived (but aren't injury free due to the debris), because it was the pressure wave that blew out the trunk and windows, and not pieces of the tank. That's why I hate FCEV proponents who claim that there are barriers in place to protect the occupants in case of an "explosion". Shockwaves aren't inhibited by barriers! Also remember that the video is of a 3500psi CNG tank. An H2 tank (at 10,000psi) would have been much more destructive as evidenced by the Norway explosion!
GRA wrote:The issue is whether or not high pressure storage, like Li-ion batteries, is adequately safe, not whether or not either is completely safe, and that can only be determined statistically as well as in the court of public opinion. In the specific case of the video you provided, what other info do we have? What kind of tank was in use? Why did it fail? Had it been repaired? How old was it? Was it required to be pressure-tested, and had it passed, etc.? Given that this was apparently in Russia, a country with a notoriously lax and corrupt safety regime, how much relevance does this particular example have to countries with tighter standards and enforcement? And so on.
As to blind faith in H2, I have none. I value it for allowing FCEVs to be ZEVs, and for its operational advantages over BEVs (for now), of greater range, rapid energy replenishment and because it allows dividing energy replenishment from where you live or work, until such time as:
1. recharging stations are universal or
2. We replace virtually the entire fleet with fewer, autonomous MaaS BEVs that can drive themselves to/from charging stations.
The capabilities that FCEVs provide will allow people living in MUDs in dense urban areas in Asia, Africa and South America, which will see the majority of population growth between now and 2050, plus Europe, to use ZEVs, something that won't be possible with privately-owned BEVs alone for decades.
FCEVs also happen to fit my own use case better than BEVs at the moment, but I have no emotional connection to either tech, let alone blind faith. They both have advantages and disadvantages, and I'll be satisfied if either or both succeed commercially. My primary goal is to get off fossil fuels, and we need at least one ZEV tech that can be successful without subsidy or mandate; neither of the above are as yet.
Baloney! You're trying to set up an equivalent judgement criteria that's not equivalent and pointless. The fact that you're trying to set that up, shows that you really don't have an issue with high-pressure storage and that your words above were empty. If you still don't get the difference, then I'm wasting my time.
Oh, I get the difference, but you're right, I don't consider that HP storage is as yet, proven to be unacceptably safe. Of course, I sleep less than six feet from a couple of steel scuba tanks filled to 3,500 PSI, which were used when I bought them and are now 12 years older. They are right next to a pair of 2,400 PSI steel tanks, also bought used (actually, they can legally be overfilled 10% to 2,640, and I do so) with the same 12 years of use by me, and the latter should be safer AOTBE, so I've undoubtedly decided that the advantages of HP storage (smaller size and weight, better buoyancy characteristics) outweigh the disadvantages in many cases, even though I have no doubt that if any
of them were to rupture, any shrapnel would penetrate the wall of the closet without difficulty and be able to reach me, with serious consequences if it did.
Of course, they are all required to be visually inspected as well as having their valves (normal and burst) maintained on a yearly basis, and hydro-pressure tested every five years. There are probably hundreds of thousands if not millions of these in use worldwide with explosive ruptures being extremely rare, so I have more than a little basis for my judgement, but it would undoubtedly be safer to store them further away from me, and if I could, I would.
It's a question of relative risk. For instance, Teslas have experienced a fair number battery fires involving thermal runaway, apparently at a much greater rate than the batteries used by other ZEV manufacturers, although it's possible that Tesla fires are more likely to be reported, and also that there are just more of them out there. Here's a list up to May of last year, although many of these fall into the "well, duh" category where the fires were the least of the problem: https://www.autoblog.com/2018/05/11/a-list-of-tesla-car-fires-since-2013/
Then we had this last month:
Tesla pushes battery software update after recent fires
The over-the-air update is going out to Model S and X cars now ‘out of an abundance of caution’
This includes the car in the video I linked to, and another one in Hong Kong in a "parking lot" (given the density of Hong Kong, i wonder if that should be "parking garage", as in the case in Shanghai). Both caught fire while parked.
Tesla packs have the highest specific energy and energy density of any BEV batteries on the market, so even assuming no differences in chemistry or thermal protection (which is not the case), you'd expect them to have a higher rate of fires. Does this mean that I think Tesla batteries are unacceptably safe? No, just less safe than others, and almost certainly still safer than fossil fuels, especially gasoline.
From memory, there are something like 240,000 vehicle fires ranging from minor to catastrophic in the U.S annually, out of a fleet of something over 250M motor vehicles. Since I don't know what percentage of those fires were caused by the loads or external sources rather than inherent to the vehicle, let's just assume they are all inherent and figure a round number of 1 veh. fire/per 1,000 veh./year for fossil-fueled ICEs. From over 100 years of knowledge and experience, we know the public and the government both judge this rate to be acceptably safe, although any steps to improve it will be welcome.
The most recent number I saw for the FCEV fleet in California was 6,300. Let's lump both H2 fires and tank ruptures together; if the rate is under 1/1,000, it will be adjudged acceptably safe. That means that this year, if we have 7 or more such accidents it would be less safe than fossil-fueled ICEs. Production FCEVs have been on the market in California for I think it's 5 years now, and I haven't heard of a single such case, although we could have had something like 10-15 total and still be no less safe than ICEs. There's no doubt that if one did happen we'd hear about it, just as we did in the case of the H2 production and fill station explosions and fires, with references to the Hindenburg and much hand-wringing. There have been no such reports.
Now, if tanks start blowing right and left and/or people start getting barbequed in their FCEVs on a regular basis at a much higher rate than ICEs, then we'd have reason to think that HP H2-fueled FCEVs aren't adequately safe, and I'd be among the first to say pull them from the fleet, but we have no such evidence as yet. Until we do, I'm okay with them on the road, although I'd certainly prefer that one of the LP H2 storage techs gets commercialized and replaces them; LP is
safer than HP, AOTBE. YMMV, but do base the decision on statistical evidence rather than gut feeling.