Smart grid - maybe smarter if not everything in it is smart

On the other hand, if you're looking at a neighbourhood with lots of houses with solar panels on their roofs, you may not want them all to be at the optimum angle and orientation. If they're all the same, you're going to get one peak generation, probably around lunch time.

If some are pointing more to the east, and some more to the west, then each will peak at a different time, helping to balance the supply. A roof at the optimum angle will produce the maximum output over the year, probably peaking in May and September when the angle of the midday sun is close to the average for the year. Shallower roofs will produce less in the winter and more in the summer, so a range of angles may also help to balance the supply.

And there may be more levelling of the emerging grid with different kinds of panels, with their performance depending on the weather conditions. For example mono crystalline will produce more electricity than other panels in low light and in high temperatures.

So thinking of the bigger picture, and thinking long term when solar panels are so cheap that people can't afford not to put them on their roofs and they want to switch the big power stations offline, all those arrays at non-optimal angles make a little more sense. And anyway, going fifteen degrees either way from the ideal due-south 35 degree inclined plane is not going to make a huge difference.