[cryptonector]

Yes, but more like power than energy. The main problem is that energy can't really be stored, so energy cannot be saved like money can (sort of). So it is really power that money buys, not energy, and only supposing power is available.

This is yet another reason that proof-of-work schemes are a disaster for society: they waste its most precious material asset!

[dredmorbius]

Stores of energy are frequently called fuels.

There are other options as well. Stored work-product (e.g., banking heat or cold when possible for later use, materials fabrication). Potential-storage mechanisms (batteries, pumped hydro, kinetic, or others). Demand-side rather than supply-side dispatch --- varying activity rather than generation or energy provision to match available capabilities.

[cryptonector]

You don't get energy and materials back out of building things for which there is no demand.

There is no way to store natural gas to meet one year's demand.

There is no way to store electric power to meet one year's demand. Not even one month's.

There is no way to store wind or solar power (see above).

Nuclear fuels, of course, can be stockpiled, but you can't demand more power than the nuclear plants that exist can produce, so having 100 years' worth of enriched uranium alone wouldn't help you produce extra power in any particularly hot summer / cold winter. Fuel is not the form in which we want energy when we turn an electric light on!

> Demand-side rather than supply-side dispatch --- varying activity rather than generation or energy provision to match available capabilities.

That's not possible. You've paid too much attention to Holdren.

You cannot make people alternate sleep/wake cycles so that we can have steady base load and no peak load. Or whatever else you have in mind for "varying demand" to match supply, unless that's rolling power outages.

Electric energy cannot be saved in any significant amount, full stop. Excess supply can be sent to ground, but excess demand cannot be met except with power generation using fuels that can be throttled very quickly (and that's essentially only natural gas). That means that electric power supply has to match demand or we must constantly run base power generation at peak demand rates and send excess to ground -- a tremendous waste!

There's no way around this.

Even if we did have batteries that were a) small, b) cheap, c) had enormous capacity, those would essentially be -when charged- coulombic bombs that have to be kept from exploding. Indeed, there are physical limits to electric energy store density where you can trivially get that energy back as power. For example, we've all seen that smartphone batteries are small explosives (recall the Samsung Galaxy fiasco), so now scale that way up and imagine what that would mean.

[dredmorbius]

Energy storage can be challenging. It is far from impossible.

And of course, all energy conversions involve losses.

Most generally, excess electrical generation can be stored as fuels. The round-trip efficiency is low (~15--20%), but the storage time is proved to multi-hundred-million-year duration.

I've looked into the literature on one variant of this which dates to the early 1960s:

<https://old.reddit.com/r/dredmorbius/comments/28nqoz/electri...>

Your other assertions are ... similarly flawed. Again, yes, challenges, but not outright impossibilities, and there are a number of other alternatives (flow batteries, molten-salt and other batteries, pumped-hydro, CAES) which you fail to consider at all. Several of those are already implemented at grid scale, others ... are at least technically possible, and may well prove viable.

[cryptonector]

Storing a year's worth of U.S. electric production in a way that one could then get it back in a similar time span is not merely challenging. It is infeasible. For one, because of the efficiency issues you mention, we'd need a lot more than a year's worth of electric production to "charge" the "battery", and since we can't dedicate all our energy production capacity to charging that battery, we can't charge it in a reasonable amount of time. Further, we'd need to have the production capacity that could consume that battery, if that battery were fuels made from CO2, say, and we'd have to have it idle except when we need it on an emergency basis -- that or we'd have to use the same kind of fuel as our primary source of electric power under normal conditions, but we're not really allowed to. Moreover, we cannot re-create fissile fuel, so this wouldn't be very dense fuel -- it would have to be chemical fuel meant to be oxidized with atmospheric oxygen. Chemical fuels are not dense enough that we wouldn't notice the storage facilities for them -- they would be enormous, consuming enormous amounts of materials and labor to build. The economic cost of all of that would be staggering -many many times the cost of equivalent amounts of energy that we currently produce-, and that cost is what makes it infeasible.

[dredmorbius]

There's no need to store a year's worth of electrical production. In most cases, a few hours is more than sufficient. Widespread shortfalls are better addressed via grid supply than storage. It might be necessary to have bridging power for a few days, possibly a few weeks, but this is still far from annual-scale in either fraction of production or duration of utilisation.

Synfuels (petroleum analogues), again, though round-trip inefficient are sufficiently energy-dense and long-term storage stable that they might serve for emergency long-term standby capacity. It's useful for other needs (industrial feedstocks and transportation fuels in aviation and marine shipping) so that some supply would likely be necessary regardless. Having standby / idle generation plant would be a capital and maintenance factor, but not impossible. There's well over a century of experience in storing strategic reserves of petroleum in both artificial and naturally-occurring storage facilities.