Unlike many here, I don't claim to be an expert at anything, much less solar power. My concern is cost benefit ratio. First, $0 annual operating cost is completely not true. There will be painting of the metal parts, the inevitable repairs to connections, and bad panels.
Next comes from the actual benefit that you derive from the solar panels. There are many studies that indicate things we think are good for the environment are actually bad. Electric cars, the pollution generated by the manufacture of the electricity and the massive pollution generated from the manufacure and disposal of the batteries makes them not as great as people would like to think. Paper plates vs washing dishes... Paper plates actually are better for the environment. The cost of the energy to clean the water, heat it, and run a dishwasher far exceeds the cost of the renewable wood for the paper plate.
This leads to my point... if you cover a parking lot with solar panels, 1, you have to have the expense of it being able to take a wind load from a hurricaine, the durability that it can take a hit from a car, the maintenance of all of those structures, plus.... you would have to light the underside of the panels, so that drivers can see... in many cases, for the entire day, not just at night. Would it even net out to be a positive, or would the costs and limited benefits out weigh the purpose of even bothering.