[ncmncm]

Hint: many places do not, in fact, experience annual reduced insolation, and can produce equally year-round. We call those places "tropics", maybe you have heard of them.

Do you think utilities store months of fuel, nowadays? Or do they rely on regular deliveries? Do you think relying on regular deliveries of ammonia, in winter, would be much different from relying on deliveries of NG year-round, as today?

[ephbit]

> ... many places ...

Yet I'd assume _most_ places in the global west still have fluctuating irradiation and wind to a degree that makes weeks worth of storage necessary.

> Do you think utilities store months of fuel, nowadays?

The utilities probably only to a certain degree. But it doesn't really matter who stores the fuel, right?

> The United States has the world's largest reported strategic petroleum reserve, with a total capacity of 727 million barrels. If completely filled, the U.S. SPR could theoretically replace about 60 days of oil imports. [1]

These reserves are of course not used to supply power plants.

But I'd bet as soon as the renewable slice of electricity generation exceeds some 50-60 % of total supply, the authorities will not have days but weeks or maybe months worth of natural gas or hydrogen or ammonia stored to supply the grid (with according power plants) over extended periods of low renewable generation.

Just thinking about how essential the electric grid is for society to work, convinces me that it won't be days worth but significantly more.

[1] https://en.m.wikipedia.org/wiki/Global_strategic_petroleum_r...

As to deliveries from around the world. Any country will of course make a trade off between the political goal of independence or self sufficiency and economic considerations. Countries that have sufficient renewable electricity generation potential to be independent from external supplies will rather try to avoid external dependency, don't you think?

Which would require storage.

Also, imagine what happens as combustion engine cars get replaced more and more by EVs. The strategic petroleum reserves probably become less important and grid stability becomes more important. And I don't think the EV batteries are going to provide enough buffer to enable a stable grid all year round.

[ncmncm]

Almost all countries have "external energy dependency" today, US conspicuously among them. Why would they all, suddenly, need independence, just because they use renewables?

You miss the point about the tropics, again. Places with reliable insolation will be exporters of synthetic fuel. None will have monopoly power, because the sun shines on them all equally. Northern countries may buy as much as they can use from them, so will not need more storage than for the time until the next shipment.

The US keeps a "strategic petroleum reserve" specifically because it has been subject to embargo by a limited group of producers. There can be no such embargo of synthetics from renewables, so no value in any such "strategic reserve".

[ephbit]

> You miss the point about the tropics, again. Places with reliable insolation will be exporters of synthetic fuel. None will have monopoly power, because the sun shines on them all equally. Northern countries may buy as much as they can use from them, so will not need more storage than for the time until the next shipment.

Imagine some non tropic country were to gradually increase its renewable electricity generation capacity. Solar on more and more roofs. The country now reaches a capacity that matches its peak electrical power consumption when the sun shines at noon and the wind blows everywhere.

Now there are two possibilities.

A. They stop increasing generation capacity. When generation is _below_ peak (because evening and no wind) this country has to rely on storage or imports.

B. The country continues increasing renewable generation capacity, so when the sun shines and the wind blows, they have excess electricity. Which they can store in batteries or as hydrogen or derivatives.

Why should any country choose A over B?

And why should they not continue to increase capacity (until all reasonable surfaces are covered) in scenario B until they maybe even are independent?

I'd say the only reason not to do that would be if imported energy were cheaper.

[ncmncm]

Even in extreme B, they may still sometimes need to import power. Or, they cannot be sure they won't ever need to. If they ever do, they will anyway know well ahead of time.

Clearly B is better, but they get to A on the way there. On the way to B, they may find they import power infrequently enough that they prefer to stop building out. That is a legitimate choice for most.

Cost is all-important, in energy policy.