Oils4AsphaultOnly wrote: GRA wrote:
You're conflating risk assessment with risk mitigation.
No, I'm talking about both risk and
Oils4AsphaultOnly wrote:Let me repeat with CNG. At low pressures (under 300psi) it's in our backyard as cooking fuel or part of the Treasure Island pyro show - completely SAFE. At 3,500 psi, it's a potential bomb, and accidents involving CNG buses are treated as such.
Completely safe, huh? So, how about 400 PSI? https://en.wikipedia.org/wiki/San_Bruno ... _explosion
Obviously, we should immediately stop using NG in pipelines, because it can explode and cause casualties.
YES, we SHOULD! That was a 30" pipe at 400psi. A SIGNIFICANT amount of fuel was present for that fire. Can you imagine how much WORSE that explosion would've been had it been at 1000psi?! I would advocate everyone switching to induction cooktops and heat pump HVAC's (as I've done), but that's not something that everyone can do. I get that. As it is now, NG pipelines is the most cost-effective existing solution. We'll move away from it, when the alternative is cheap enough. However, that doesn't mean I'm advocating for us to move to coal either, which is cheaper still.
I'm glad to see that you consider the risks of coal greater than the rewards. What you're saying is that there are varying levels of risk to various fuels and advantages and disadvantages, and we as a society choose which are most important to us. In the case of San Bruno, 8 people died. Big deal. Here's the biggest death toll I could find from a NG explosion in the U.S.:
http://www.history.com/this-day-in-hist ... n-in-texas
Nearly 300 students in Texas are killed by an explosion of natural gas at their school on this day in 1937.
The Consolidated School of New London, Texas, sat in the middle of a large oil and natural gas field. The area was dominated by 10,000 oil derricks, 11 of which stood right on school grounds. The school was newly built in the 1930s for close to $1 million and, from its inception, bought natural gas from Union Gas to supply its energy needs. The school’s natural gas bill averaged about $300 a month. Eventually, officials at Consolidated School were persuaded to save money by tapping into the wet-gas lines operated by Parade Oil Company that ran near the school. Wet gas is a type of waste gas that is less stable and has more impurities than typical natural gas. At the time, it was not completely uncommon for consumers living near oil fields to use this gas.
300 kids dead in a single event is sure serious, isn't it? I've already mentioned the number of people who die in the U.S. every year in auto accidents (over 100/day), but how about the opioid epidemic, which is responsible for 116 dead every day in the U.S., i.e. every three days more people die of opioid overdoses or auto accidents than died once, 80 years ago in the worst pipeline disaster in U.S. history. Here's a partial list of world pipeline accidents: https://en.wikipedia.org/wiki/List_of_p ... _accidents
I expect if you totaled all the dead and injured up, it would be far less than 1 week's worth of auto or opiod deaths in the U.S. alone.
Or how about the U.S. obesity epidemic: (36.5% of all American adults and 17% of children are obese per CDC 2014), as cardiovascular disease is responsible for almost 25% of deaths in this country, and is the leading cause. You're worried about a few deaths in spectacular fashion which happen years or decades apart, instead of the massive but diffuse health risks of our daily life.
Oils4AsphaultOnly wrote: GRA wrote:
Oils4AsphaultOnly wrote:H2 is compressed up to 10,000psi. That number needs to be taken VERY seriously. Heck, even Toyota forbids the use of their tanks after a limited age, regardless of the condition of the tanks!
I imagine the main reason is because there's as yet not enough data on CFP tanks to certify them for longer. My scuba tanks are certified to 3,500 PSI and 2,640 PSI (the latter is for tanks that are nominally 2,400 PSI, but a 10% overfill is allowed as long as they pass an extra expansion test), and both have to be pressure tested every five years and visually inspected every year. However, they're steel, and we've got over 100 years of experience with them in that kind of service, with gradually increasing pressures and test intervals as experience was gained and metallurgy and test methods improved. Here's some reasonably current info for Type 4 composite tanks:
https://energy.gov/sites/prod/files/201 ... v_wong.pdf
No one has suggested that tanks under high pressures are as safe as containers that are under low or no pressure.
COMPOSITE TANK TESTING,CERTIFICATION, AND FIELD PERFORMANCE
The question is what is the level of risk compared to other options, and how does the risk balance against the advantages and disadvantages of those options.
That's exactly what you're advocating when you claim that compressed H2's risks aren't being appropriately balanced against their benefits. From your position, either their benefits are so great that their risks are balanced against it, or that their risks are small enough to justify the small benefits gained. I'm from the camp that sees insufficient benefit for the risks that it poses.
Yes, I do think the benefits are greater than the risks. I believe we need to stop burning fossil fuels for transportation (and everything else eventually, using the remaining fossil fuels for feedstocks for plastics etc. if we can't find substitutes) and replace our vehicles with ZEVs, with all the health benefits that go along with them, and which far outweigh the risks of the occasional explosion or fire:
http://www.greencarcongress.com/2018/01 ... 4-epi.html
2018 Environmental Performance Index: Air quality top public health threat
Recent research cited by the EPI suggests that around five million people die prematurely every year due to air pollution, accounting for approximately one in every ten deaths annually.
Pipeline and tanker explosions? BFD.
However, you'll be happy to know that H2 providers are now shifting to liquid H2 tanker transport, not from safety concerns but simply because usage and storage per H2 fueling station is growing, and it takes multiple compressed H2 fuel tanker trips per day to meet demand, where a single LH2 tanker can easily meet it. Naturally it won't eliminate all risk, because the stations may still store relatively large amounts on site in compressed form.