There’s a solar farm just north of Winfield Village, with ranks of solar arrays that turn from pointing east to pointing straight up to pointing west. (Oddly, they’re not arranged to point south. I assume the people who built it knew what they were doing, but I’ve been puzzling over it for a couple of years.)

The directions they point (and the timing of the changes) seem odd, and I’ve been trying to characterize the whole thing.

I initially assumed that they’d be programmed to point a particular direction based on ephemeris data about where the sun will be, but that seems not to be the case.

Here’s one piece of data: At dawn they do not turn to point east. Rather, they turn to point straight up:

Array of solar panels pointing pretty much straight up

It is only after the sun is well up that the panels turn to face east.

Last night, perhaps an hour before sunset, they were pointed about halfway between west and straight up. Which kind of makes sense, as there were clouds to the west, so they clear sky straight up was probably as bright as the sun behind the cloudy sky.

My current working theory is that the panels turn to face whatever direction produces the most power, regardless of where the sun is in the sky.

Array of solar panels pointing mostly west.

I’ll continue to watch, and try to characterize their behavior further.

Maybe I’ll even get in touch with the University and see if they can provide a link to a description!

Yesterday’s eclipse prompted me to go look at the day’s power production from the University of Illinois’s solar farm.

Just eyeballing the graph, I’d estimate that eclipsing 94% of the sun reduced power production by about 94%.

The solar farm is exactly one mile north of Winfield Village. Jackie and I got a tour of the facility a couple of months ago and I got some pictures besides the one at the top, but haven’t gotten around to writing my solar farm post yet.