Speaking from quite the unique experience today, I can confirm this. Most of the west-southwest corner of the park (namely Action Zone, though also including Oktoberfest and International Street) was off and on most of this afternoon, with the International Street shops, the Festhaus, and select Action Zone rides (Flight Deck, Drop Tower, Congo Falls, Delirium) generally remaining shut down for the duration of one very busy, humid, and warm Fourth of July afternoon. It was incredibly odd to walk (momentarily) into an almost completely dark Festhaus, the lights from Panda Express being the only electrical source of illumination... Of course, when I realized the A/C was out, too, it didn't take much thought to walk right out the same entrance.
(I actually had a mildly hilarious conversation with an Emporium employee about it, on a side note. When we asked him about the power problems, he responded with, "Think of the creepiest scene you can think of from a movie. Now dim the lights on it. A lot. And crank up the creepiness factor by like ten thousand. That's what the warehouse is like right now." )
I have quite a bit of sympathy for Guest Relations folk tonight... I'm sure they got quite the earful (or five, ten, fifteen...) As I understand it, the park has not been offering refunds for today. Viking Fury and even the Eiffel Tower (as well as the aforementioned AZ rides) were off and on all day on a major national holiday, and there was no really great escape from the heat since at least half of International Street, Action Zone, and Oktoberfest had ZERO power in the hottest part of the day. This lead to full queues for at least Diamondback, Vortex, and The Crypt, the last of which leads me to believe that Flight of Fear most likely had a high demand since it's also indoors and therefore also (assumed to be, anyway) air conditioned. Yes, I don't think you could pay me enough to be a poor GR soul today...
EDIT: Now that I think about it, wasn't it just a season or two ago that the park was experiencing similar power issues around June/July? I clearly recall the odd situation where the power issues had Blue Racer down but weren't affecting Red Racer.