We’ve all heard about the potential disaster another Carrington Event like solar flare could cause to our power grid. Melted transformers taking weeks, months, maybe years to replace. The end of civilization as we know it.
Something not mentioned, so I’m going to mention it here, is the effect such an event would have on nuclear reactors. Nuclear reactors require constant cooling water flow. Even when a plant is shut down, control rods in place, it still generates a tremendous amount of heat because most of the fission products continue to decay for some time.
Nuclear power plants get the power to cool the reactors off site because even if the reactor is not operational it still requires cooling to prevent a melt-down.
This off-site power is delivered via high voltage lines that have transformers at each end of the circuit. These lines are subject to induction of huge low frequency currents that could burn out said transformers in the event of a large solar event.
In a massive event it may not be possible to keep the backup generators fueled. When they run out of fuel you have a meltdown like Fukushima. A large solar event taking down our power grid could result in hundreds of Fukushimas right here at home.