Can't remember the sauce but when I was researching EMPs I found out that the US has 300 very large transformers in it's electric grid. These are made in China. And…. they are back ordered. I read it would take 3 years to replace. I will attempt to retrace my steps. But I posted it in my college course I was teaching at the time, so I know it's was real.
http:// energyskeptic.com/2015/power-transformers-that-take-up-to-2-years-to-build/
https://
energy.gov/sites/prod/files/Large%20Power%20Transformer%20Study%20-%20June%202012_0.pdf