Epistemic status: some errors pointed out and since disentangled in the comments. LLM-use for much of the research. I regret having published this without going through academics online first, and will do so now, and edit the post accordingly. There is surprisingly little research on solar storms' effects on electric grids and solutions to those out there.

Most of civilization's electricity is generated far off-site from where it's delivered. This is because you don't want to be running and refueling coal/gas/nuclear plants inside cities, hydraulic/wind power can't be moved, and solar panels are cheaper to install on flat desert terrain than on cities:

So in practice this means running power over hundreds or even thousands of kilometers. E.g. here are the Chinese long-distance lines:

American long-distance lines:

These are simplified maps meant to illustrate how insanely long power lines get. The true shape of solar storm vulnerability looks like a spiderweb overlayed on population density (see below), which you can visualize on this website.

The fact that civilization finds it economical to generate its electricity hundreds or thousands of kilometers away from its population centers is rather mind-blowing given the infrastructure involved. For example, the Tucuruí line spans the Amazon rainforest and the Amazon river to supply the Brazilian coast with inland hydropower:

Brazil works behind scene to greenlight Manaus-Boa Vista transmission line

China's Zhoushan Island crossing involves lattice pylons taller than the Eiffel tower and spanning 2.7 kilometers of open sea:

CHINA-ZHEJIANG-WORLD'S HIGHEST POWER PYLON-CABLE CONSTRUCTION (CN)

World's tallest transmission tower capped in E China's Jiangsu - CGTN — The Yangtze river crossing, with the tallest transmission towers on Earth at 1.1X the height of the Salesforce tower in SF.

But electricity traveling through a wire generates waste heat! So much so that if you tried sending electricity exactly as it was generated to buildings thousands of kilometers away, it would all be lost.

The solution is that for a given amount of power, higher voltage means lower current.

So the trick is: step the voltage way up before sending power long-distance (reducing the current and therefore the losses) then step it back down to usable levels at the destination.

The machines that do this are large power transformers (LPTs), which are massive rings of iron submerged in mineral oil and wrapped in kraft paper and copper coils. There are maybe abo...

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