re: Congress warned that NoKo could take out power grid, killing 90% of Americans

The entire grid goes down as the result of a massive EMP strike and I can buy the numbers of deaths being in the high 80 to 90%... The likelihood of that being triggered by North Korea is not very likely...

However, I could see them taking down the grid on the West Coast without much trouble... That grid is not in great shape to start with (brownouts often) and it would not take a lot to overload it... The grid is complex but when one part fails, it typically causes another part to fail, and then another until that grid collapses...

For those of you saying it will take a couple of days to get it back up, in the right scenario it could take months or even years to get the grid back fully operational... I am currently working a project, where a major power company has a 6-month lead time on one substation transformer just for one example...

Also, you really need to think about what isn't going to be working post EMP, especially in the immediate area:

Every car on the highway is dead where it sits.
Every computer, cell phone, electronic device.
Public Transportation is down.
Water and sewage is down.
Elevators are not working.
Hospitals do not have power and gen sets are fried.
Your fridge and freezer are toast.
Electronic payments systems are down.
Banks are down.
Stores are down.
Pharmacies down.

Need me to go on?

Oh and for all you baws in Alabama that are all of a sudden going to live off the land, good luck:

You might garden but without non-GMO seed that is one season, not to mention done by hand.
Everyone else is going to be hunting and fishing.
You are walking everywhere you go.
How are you going to store food?
Where are you getting water?
Do you take a daily medication for life support? Are you diabetic? Insulin dependent, you are fricked.

Need me to go on?

Now, the government has been aware of the vulnerability of the grid for years. The power companies have admitted they are not prepared for such an instance. However, the "problem" has been deemed too expensive to prepare for and they will ignore it. It is what happens when the presence of a potential problem is weighed against likelihood and cost. In other words, the government sees the potential loss of life as an acceptable risk.