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Comment by nicoburns | Hacker News Reader

> so you'd need to have something like 10x solar if you wanted the overcapacity strategy to work, which also make things prohibitively expensive.

In the short-term, gas backup for such scenarios (which are relatively rare, and during which renewables will still operate at some non-100% fraction of the required energy) seems like it might be a reasonable option: we could probably get to (pulling numbers out of thin air) 95% renewable generation or something that way.

Longer term, we'll definitely need some kind of long-term storage though. Perhaps synthetic fuel driven by overcapacity renewables during peak generation times might be an option here?

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> we could probably get to (pulling numbers out of thin air) 95% renewable generation or something that way.

No, and it's the problem with pulling numbers out of thin air.

I wrote on that topic a few years ago with a simulation being done on real data from RTE (French electricity transport network) if you're interested[1] you can even play with the LibreOffice spreadsheet[2] by yourself if you like. (Caveat: everything is in French).

And keep in mind that France is actually favored compared to many other countries when it comes to wind stability because it has three wind regions with different dynamics (even though they aren't entirely independent either).

[1]: https://bourrasque.info/articles/20180116-moulins-%C3%A0-ven...

[2]: https://bourrasque.info/images/20180116-moulins-%C3%A0-vent/...

> gas backup for such scenarios (which are relatively rare, and during which renewables will still operate at some non-100% fraction of the required energy)

Now you have built two energy systems and one of them has to be on standby and ready to be used only rarely. Cross your fingers and hope everything still works. You also have to maintain long term storage of gas, staff that knows how everything operates, etc.

> Now you have built two energy systems and one of them has to be on standby and ready to be used only rarely. Cross your fingers and hope everything still works. You also have to maintain long term storage of gas, staff that knows how everything operates, etc.

Well yes, except that the backup system happens to be already built. There's definitely a maintenance cost associated with this, and long-term (beyond the lifetime of existing stations) this wouldn't make any sense. But in the short-term the costs associated with this are relatively low.

It seems disingenuous to talk about "short-term" costs when we are talking about grid-scale energy systems. It is the long-term costs that are important when evaluating capital intensive systems.

That seems to be less the case if one is evaluating continuing to use existing systems for which the up front capital costs have mostly already been paid.

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