My understanding is that we actually don’t have much of a warning (under an hour), since a CME has to reach the satellite at the Lagrange point between Earth and the Sun for us to know it’s about to hit Earth. According to the article below, this includes power companies, but I remain skeptical that there’s enough organisation in place to shut down the North American, European or Asian grids in 15 minutes.
My understanding is that we actually don’t have much of a warning (under an hour), since a CME has to reach the satellite at the Lagrange point between Earth and the Sun for us to know it’s about to hit Earth. According to the article below, this includes power companies, but I remain skeptical that there’s enough organisation in place to shut down the North American, European or Asian grids in 15 minutes.
https://www.space.com/coronal-mass-ejections-cme