how possible is a permanent power outage in the US & why would it happen?

Permanent?
How permanent?

The longest ever power failure caused by a Coronal Mass Ejection (what peasants call a "solar flare" even though it is not) was nine hours for six million people. And most of the 9 hours were spent trying to understand what had gone wrong.

Nowhere near as much as the man-made failure of 2003, caused by the failure to clear branches around a high-voltage power line in Ohio, causing a failure that affected 55 million people, some of them for up to two days.

The grid that served the 9 million people that suffered the Sun-triggered failure in 1989, was fixed so that this problem would never happen again (or would be easily fixed within minutes next time).

However, fixing the grid costs money. Maybe the private companies running the grid for the benefit of their shareholders could not spare that much money. I don't know.

But "permanent"?

Permanent...? I wouldn't say it's possible at all, except in the case of removing *all* the wires from a powerstation...

As long as there's a way to run magnets close to wires, you'll be moving electrons down that wire - and presumably out to customers of the electric company. I can't think of anything that would stop that from happening; unless magnetism were to suddenly die away.... but, we'd be in a lot worse trouble than a power outage should that happen....

Raymond's answer is pretty good but I would add that the 2003 outage although caused by trees, the trees were not the root cause of this outage. When deregulation was placed into existence for electric utilities, Federal guidelines attempted to spur competition in a manner that would increase the number of electrical suppliers to the grid. They did this by passing a temporary law that prohibited rate increases while requiring the utilities to maintain the existing performance levels for 10 to 15 years depending on the particular area of the country. Trees that would have been addressed on a shorter cycle we not cut as often as they were in the past.

This condition was similar to asking you to produce a shirt for $10, then adding your $5 for profit, etc. Then telling you that for the next 10 years you were not allowed to increase the total cost of the shirt beyond the $15 you were presently selling it for. So the cost of labor, health insurance, materials, fuel, taxes continue to increase but you are not allowed to increase the cost of your shirts to keep up. What would you do to keep your business going? Well that is exactly what the utilities did. Cut manpower, reduce maintenance costs (mostly by extending maintenance periods), reduce fleet size, contract out work so that you could stop the work without having a fixed cost, etc. Tree trimming periods were extended thus exposing us to tree contact possibilities.

Next as part of the deregulation effort, FREC required new regional transmission control centers for the grid. MISO and PJM were two bulk power controllers that were in the process of transferring control from PJM to MISO and MISO's computer system was running in simulation mode while MISO thought it was running in real time. Thus, MISO did not see the original line trips caused by the tree contacts and they did not see the resulting shift in load to other lines which were in turn overloaded. As they tripped off the remaining lines overloaded as did some of the generation stations. The system automatically protected itself from further overload by clearing the overloaded area of the grid which cascaded from the upper mid-west into Canada, down into New York and parts of New Jersey. The vast majority of the PJM portion of the grid remained in service since both the protection relays and actions of the PJM operators broke the PJM section of the system free from the grid.

Now to a permanent outage, not likely as has been stated, however, a large CME could cause major transformer damage since the protection and monitoring systems on the gird have not been kept up to date. Further an EMP of sufficient magnitude could also cause transformer and circuit breaker failure on a large enough scale that it may take years to restore. If you consider that the USA no longer has manufacturing capability to make large power transformers in this country and would be only one of possibly many countries looking for replacements, it could take a long time before delivery would occur. We might be operating like they do in India.

Hope this helps,

Newton1Law

It is not possible for a "permanent" power outage to occur anywhere. Much less and cover an entire nation. It can't happen, under any situation. Anything that caused a power outage could simply be repaired. It might take a while to repair, depending on the damage. But "permanent" is impossible.

Well, we had one for hundreds of years up until the early 20th century.