How vulnerable was Germany's electrical grid in WWII?

Well, coal must be mined…by humans. So the solution would be:
-burn down the residential towns housing the miners
-destroy the railheads at the mines, and the coal loading yards
Miners have to eat, sleep, and live-incendiary bombing would have made that impossible.
This would have made far more sense than bombing a city like Dresden.
Dresden was a mistake for two reasons:
-it killed a lot of civilians to no good purpose
-it had almost zero impact on German war industry
Speer relates that the main weak point (besides petroleum) was steelmaking-and steel depends upon coal.

I was given to understand that the ME-262 couldn’t be produced because the engines and airframes were manufactured in different places, and the railways were bombed to the extent that the Germans couldn’t get the engines and airframes together.

The Dresden bombings killed “a lot of civilians”, yes, but not the hundreds of thousands that Goebbels lied about(he, literally, seems to have placed an extra zero on the real number of casualties). ISTM that the appx 20,000 dead at Dresden is similar to that of other raids on other cities by both sides, the main difference being that the Dresden deaths happened in one night.

As to it having “almost zero impact”, I believe that Dresden was the only possible marshalling center in the east left for the Germans by early 1945. In other words, with Dresden gone, the notion of organized German counter attack also vanished.