I live in San Luis Potosi, Mexico. I see many solar panel installations in the area, but I see few that are correctly aimed at the decent production of electricity.
One supposes of the purpose of solar panel installation is to generate electricity – if that were really the case then the installers would aim the panels in a direction and at an angle from horizontal, that is reasonably close to those directions and angles that obtain the best harvest.
From actual experience, as well as simple trigonometry, the panels ought to be perpendicular to the sun’s rays for any given day and time, but pivots to constantly move large arrays of panels are not practical in many cases, so there often must be trade-offs.
For best average annual harvest a string of panels should be at an angle from horizontal that is close to their earthly latitude (for our area, roughly 38 degrees) or a little steeper to compensate for shorter days and less bright sunlight in winter (perhaps 45 to 50 degrees).
In addition, the panels should aim south or reasonably so. Indirect light produces negligible electricity, so east; north and west exposures are ineffective.
Around SLP, I see some expensive solar arrays that are nearly dead-flat, some on residential units that are aimed north, and some in a high school parking lot that is aimed due west but could just as easily have been aimed due south.
Panels pointed due west will have a so-so harvest for a few hours each day but during a few months each year. The rest of the time, they will produce next to nothing.
None of these installations will produce as much power as if they were better aimed. Parking lot installations can easily be at 40 or 50 degrees from horizontal, and can also be aimed south or nearly so.
The loss of shade to the parked cars should be less important than the loss of power generation due to improper aiming. Apparently not.
Simple calculations show that panels inclined at 40 degrees can be expected to harvest three times as much electricity as horizontal panels, integrated over a full day, at the winter solstice, generate 60% more at the spring or fall equinox, and still make 12% more than flat panels at the summer solstice. The only time horizontal panels work for you is in the middle of summer.
Apparently, the purpose of some solar panel installations is to harvest tax credits rather than to harvest solar power. We the taxpayers who subsidize solar installations should demand a refund of tax credits paid for badly aimed installations.