That document is a very interesting read though, thank you. I don't fully trust insurers though - it's in their interest to create a feeling of risk.
Yes, but the timing of those fixes could be an enormous problem
From what I've read, a large part of the problem will be burnt-out transformers all over the grid, from the major stations down to the street-level. Replacing any one of those is only a job of a few hours, when you have one available. The problem is that fabricating them takes a long time, and there is nowhere near enough inventory to replace the numbers that would fry in a Carrington-like event (or an EMP attack). It could take YEARS to replace them, during which time the economy is pretty much back to the 1800s, but with 2000s-level population to feed.
The estimates to create a stockpile of transformers so that they could be replaced in weeks-to months range around $500 million. It would give the nation a huge strategic economic advantage to be able to fully recover on a timescale of double-digit weeks instead of years. But, since the problem is so un-sexy that it is never brought up (the last infrastructure bill would have been a good time to do so).
Even if we could individually have power with rooftop solar+battery (also sufficiently protected), it'd be hard to thrive with the entire transport web broken (no grid electricity to pump gasoline/diesel, etc.).
Still, I want to know how vulnerable is rooftop solar, and what it would take to protect it (and prevent an event from burning down the house). Any experts have some pointers?
It also isn't correct to assume that the grid is wholly unprotected. Substations have extensive protection in the form of interrupters. We will lose power in a Carrington scenario, potentially for days, but there won't be an apocalypse of exploding transformers. If that happens, nobody is going to care too much about charging their Teslas. They will be too busy fending off hordes of radioactive zombies.
At least one electricity network on the west coast of Norway already does this to cope with the inevitable damage caused by seasonal thunderstorms.
You make a good point about rooftop solar+battery. Perhaps an event like this would make us more open to decentralised energy production.
Regarding how vulnerable solar panels are - in my limited understanding the problem comes from things that will induct electrical currents from EM, so basically anything with long wires (transmission lines and transformers etc.) So I would guess that semiconductors like solar panels would not be damaged directly. I'd also like to hear from any experts though.
That really depends on how much you'd need to spend I think to prep.
There was a US commission evaluating the threat of an EMP attack (http://www.empcommission.org/docs/empc_exec_rpt.pdf) which seems to suggest that radiation-hardening transformers for such an event would also seem likely to protect them from failing due to geomagnetic storms.
The additional cost for radiation hardening:
> New units can be EMP-hardened for a very small fraction of the cost of the non-hardened item, e.g., 1% to 3% of cost, if hardening is done at the time the unit is designed and manufactured. In contrast, retrofitting existing functional components is potentially an order of magnitude more expensive and shouldbe done only for critical system units.
For that sort of overhead I think that it's justifiable to require it of new transformers at least.
So it certainly does matter, but there are different risks that each demographic takes.