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Small-Scale Question Sunday for December 7, 2025

Do you have a dumb question that you're kind of embarrassed to ask in the main thread? Is there something you're just not sure about?

This is your opportunity to ask questions. No question too simple or too silly.

Culture war topics are accepted, and proposals for a better intro post are appreciated.

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You're right, I don't actually go and prove that it is a good proxy. But the reason why I believe that is simple - that's the only real way we have to determine if a given power source can function viably in a modern western society, and the points where that connection breaks are fairly easy to identify and take precautions around. Actually measuring KWh is definitely worthwhile and there are analyses you can make with regards to it, but it gets exceedingly complicated in a way that finances avoid.

Well, while it's true that financial profit is the only way to have a power source function in a modern society, but the reasons are completely different than "Energy Returned on Energy Invested" and are subject to rather dramatic changes. Something as simple as an increase of energy prices can completely change the result, and that's without going into all the way by which costs of nuclear power have been artificially increased. By contrast a negative EROEI means you're up against the laws of thermodynamics and there's literally nothing you can do to make that power source work. Yes, it's complicated to calculate it in KWh, but it's really the only way to properly make the argument. A financial analysis does not avoid any of the pitfalls of actually measuring energy requirements, and it introduces many inaccuracies of it's own.

How reliably was that power generated? Was it limited to specific times (power that can only be generated in off-peak hours and can't be stored isn't as useful)? For the purposes of determining whether or not a given power source can feasibly supply power to a first world economy, finances are one of the best tools we have.

I don't think financies measure any of these things at all, which is why I think you should stop claiming it's about EREOI (or actually show the negative energy returns). Finances measure opportunity costs, and not even relative to other energy sources, but relative to all other things in the economy, so it's not really a good tool for this sort of analysis at all.

Mining, transporting and enriching uranium tends to consume enough energy that the return isn't terribly worthwhile.

Transport costs next to nothing in terms of energy. If you want to make the argument that it's because of mining or refining, be my guest, by provide numbers in terms of actual energy.

A financial analysis does not avoid any of the pitfalls of actually measuring energy requirements, and it introduces many inaccuracies of it's own.

You're right, though it is more useful for things like "Is this worth using in the world we actually live in as opposed to the one filled with spherical cows" - hence my preference.

Transport costs next to nothing in terms of energy. If you want to make the argument that it's because of mining or refining, be my guest, by provide numbers in terms of actual energy.

As far as I can tell from the literature I have available to me, nuclear has an EROI ranging from 5-15 when you ignore the studies that give a wildly inflated amount by leaving out key steps of the process (if you judge it solely by how much energy is in a given amount of uranium fuel pellets it blows oil out of the water - but that's not really helpful).