To estimate the scale of such a failure, report co-author John Kappenmann of the Metatech Corporation looked at the great geomagnetic storm of May 1921, which produced ground currents as much as ten times stronger than the 1989 Quebec storm, and modeled its effect on the modern power grid. He found more than 350 transformers at risk of permanent damage and 130 million people without power. The loss of electricity would ripple across the social infrastructure with “water distribution affected within several hours; perishable foods and medications lost in 12-24 hours; loss of heating/air conditioning, sewage disposal, phone service, fuel re-supply and so on.”
We have posted on this already, but this story comes with a cool map showing the percentage of transformers affected by the modeled storm in each state.
It is odd, to me, how unevenly it is distributed. I would have thought there would be some relation to the built up nature of the power grid in each state. But Texas with no transformers at risk? Florida with no transformers at risk? And then we have Penn. at 55% and Oregon at 72%. The spreading is very puzzling.
One thing you have to keep in mind is that the effects of a magnetic storm are worse the father north you are. Closer to the equator you are, the better protected you are. If we were talking about an emp burst from a high altitude nuclear burst the map would be different.
There are other factors as well. Such what type of protection the transformers have and how large of a grid each transformer supports (that is because the lines that the transformer feeds amplifies current being feed into them.
Those are just the things that I can think off of the top of my head. I have not had time to hunt up the original study to see all of their methodology.
But I am pretty sure that the reason that Florida and Texas have no transformers at risk is due to the fact they are closer to the equator. The variation in the the Northern states is what I am not sure of. It would be interesting to fine out why they varied so much.