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> There is a legal floor of ~250M, after which it is reserved for government national defense. There is no "government national defense floor". As far as I can

by ndiddy 13d ago

> There is a legal floor of ~250M, after which it is reserved for government national defense. There is no "government national defense floor". As far as I can tell, this originates from someone misreading the SPR drawdown laws and then a bunch of people parroting it. The ~250M "floor" (really 252.4M) only applies for SPR drawdowns that aren't required by a severe energy supply interruption or to meet US obligations under the international energy program. Deciding what qualifies as a "severe energy supply interruption" is left up to the president. Essentially there's nothing stopping the president from emptying the reserve entirely. See sections d and h here: https://uscode.house.gov/view.xhtml?req=(title%3A42+section%3A6241+edition%3Aprelim) https://uscode.house.gov/view.xhtml?req=(title%3A42+section%... > Public analyses have said that the cavern integrity becomes threatened once levels fall below 300M. This isn't how the SPR works. They withdraw oil from it by pumping in water (oil floats on water, so the oil goes to the top). This means that the caverns won't cave in or something if there's too little oil, since they'll have the same volume inside them. What does wear out the SPR is drawing down at all, since the water erodes the caverns. The problem is cumulative, not caused by levels going below a certain point. There's a good article that goes over how the SPR works and its current status here if you're interested: https://files.gao.gov/reports/GAO-26-106918/index.html https://files.gao.gov/reports/GAO-26-106918/index.html

fc417fc802 13d ago
Either way it seems the US has somewhere from 1 to 8 months before accounting for reductions due to national considerations. That's concerning no matter how you frame it. What's the outlook for the other major economies?
- disgruntledphd2 12d ago
  Much, much worse for the EU, probably about the same for China (based on their actions so far).
omgwtfbyobbq 13d ago
The problem with drawdowns is they can and have compromised the structural integrity of the caverns used in the SPR. Like oil, they're a finite resource and should be used judiciously. https://www.osti.gov/servlets/purl/2585591 https://www.osti.gov/servlets/purl/2585591
- stouset 13d ago
  I love that you think the current administration will actually consider this when deciding whether or not to suck it dry anyway.
  - SlightlyLeftPad 13d ago
    Belief in science is a prerequisite.
    - pseudohadamard 12d ago
      Don't you mean disbelief in science? It's really weird how in Europe having a PhD in X is seen as a good thing for being the Minister for X while in the US having to get an aide to unlock your cellphone for you is seen as a good thing for the same post.
- ndiddy 12d ago
  Right, that's what I meant by the problem being cumulative rather than caused by the actual amount of oil. The GAO article I linked goes into this: > The SPR caverns that were built by DOE were designed to be geomechanically stable for up to five full drawdowns. Repeated partial drawdowns followed by refill can leach a single part of a cavern repeatedly, leading to undesirable shapes. After Congress directed DOE to begin conducting regular non-emergency mandated sales from the SPR starting in 2017 to help manage the federal budget, DOE tasked Sandia to provide a yearly update on the number of drawdowns each cavern had remaining since the caverns were being used regularly to withdraw crude oil. In May 2025, Sandia reported that the majority of the SPR’s caverns (47 of 60—about 78 percent) had at least four remaining available drawdowns as of the end of calendar year 2024, and all but one cavern had at least one remaining available drawdown.
nerdsniper 13d ago
The caverns have salt walls. The water erodes the salt caverns.
tialaramex 13d ago
Thanks for the link, I didn't know very much about how this is implemented and now it's much clearer. I fully expect to see the same things I've just learned on a Youtube video or cable TV news some time from now when stuff goes badly wrong and it doesn't mesh with the simple "Huge metal tank somewhere" picture of such a reserve I'd imagine the average voter has. Like Britain's ageing gas mains this feels like a measure which should have become irrelevant just as it would otherwise need renewing, a huge saving - but of course we (as a species) will always procrastinate so that was never going to happen. For the next 5-10 years Britain will continue replacing pipelines to deliver a fossil fuel (natural gas, methane, for heating) we should have long since stopped using but didn't.

by ndiddy 13d ago

fc417fc802 13d ago

Either way it seems the US has somewhere from 1 to 8 months before accounting for reductions due to national considerations. That's concerning no matter how you frame it. What's the outlook for the other major economies?

disgruntledphd2 12d ago
Much, much worse for the EU, probably about the same for China (based on their actions so far).

omgwtfbyobbq 13d ago

The problem with drawdowns is they can and have compromised the structural integrity of the caverns used in the SPR. Like oil, they're a finite resource and should be used judiciously. https://www.osti.gov/servlets/purl/2585591 https://www.osti.gov/servlets/purl/2585591

stouset 13d ago
I love that you think the current administration will actually consider this when deciding whether or not to suck it dry anyway.
- SlightlyLeftPad 13d ago
  Belief in science is a prerequisite.
  - pseudohadamard 12d ago
    Don't you mean disbelief in science? It's really weird how in Europe having a PhD in X is seen as a good thing for being the Minister for X while in the US having to get an aide to unlock your cellphone for you is seen as a good thing for the same post.
ndiddy 12d ago
Right, that's what I meant by the problem being cumulative rather than caused by the actual amount of oil. The GAO article I linked goes into this: > The SPR caverns that were built by DOE were designed to be geomechanically stable for up to five full drawdowns. Repeated partial drawdowns followed by refill can leach a single part of a cavern repeatedly, leading to undesirable shapes. After Congress directed DOE to begin conducting regular non-emergency mandated sales from the SPR starting in 2017 to help manage the federal budget, DOE tasked Sandia to provide a yearly update on the number of drawdowns each cavern had remaining since the caverns were being used regularly to withdraw crude oil. In May 2025, Sandia reported that the majority of the SPR’s caverns (47 of 60—about 78 percent) had at least four remaining available drawdowns as of the end of calendar year 2024, and all but one cavern had at least one remaining available drawdown.

nerdsniper 13d ago

The caverns have salt walls. The water erodes the salt caverns.

tialaramex 13d ago

Thanks for the link, I didn't know very much about how this is implemented and now it's much clearer. I fully expect to see the same things I've just learned on a Youtube video or cable TV news some time from now when stuff goes badly wrong and it doesn't mesh with the simple "Huge metal tank somewhere" picture of such a reserve I'd imagine the average voter has. Like Britain's ageing gas mains this feels like a measure which should have become irrelevant just as it would otherwise need renewing, a huge saving - but of course we (as a species) will always procrastinate so that was never going to happen. For the next 5-10 years Britain will continue replacing pipelines to deliver a fossil fuel (natural gas, methane, for heating) we should have long since stopped using but didn't.