In the event of a hypothetical attack—like two nuclear detonations above the U.S. to take down the grid—the damage might not be as extensive or irreparable as feared. Substations directly under the EMP’s pulse could be heavily damaged, but the rest of the grid might recover quickly, mostly by just replacing blown fuses and filters. That said, substation transformers that sustained severe damage would take longer to repair or replace. Those are big, heavy, expensive devices and we do not have a lot spares.

.