[PA Engineer]

It is real and would absolutely WRECK our power grid of long lines (essentially perfect antennae for the EMF of the pulses.)

The greatest vulnerabilities are the substation transformers. There are not that many spares stockpiled. I believe many local distribution transformers will survive.

[Blueflag]

Yes. The EMF inducted into the long lines would indeed fry the step up/down transformers and the switching gear in the substations.

[DuncanWaring]

The greatest vulnerabilities are the substation transformers.

About five years ago a large transformer supplying Phoenix cooked itself (inconveniently in the middle of the summer).

The nearest one was in Oregon, if I recall correctly, and had to be shipped to LA by barge and then transported by special heavy-lift truck to Phoenix, at about 5 MPH.

Overall, the process took several weeks.