This is the penstock for the power house. There's a bar rack and screen to stop logs and other debris, as well as head gates that can be closed to stop the water flow. You can see the vertical tracks that the head gates run in, as well as a chain fall* for raising them.

I would have loved to get inside for an impromptu tour. Alas, the owner of the truck didn't finish his rounds (or maybe his nap) while I was there.

I could see the switchgear through a window, but not the alternators.

*Interesting (to me, at least) historical footnote: a relative of mine patented a chain hoist, and manufactured them at McCollum Hoist & Manufacturing Co. in Downers Grove, IL. My father took me on a tour of the factory nearly 55 years ago. I recall that they had big concrete cylinders set in the floor to use as weights for proof testing the hoists. I'd love to find one of their hoists, but so far, no luck.