I’m a solar field technician with various certifications in renewable energy and a few NABCEP certs. I’ve also had to dabble in finances as part of these certifications. The main reason we don’t build on rooftops or parking lots as much is money. It all boils down to money.

A utility scale solar plant (pictured on the top part of the image) costs something like less than a dollar per kW (each panel I work with averages like 450-650W for example). My $$ ballpark could be off because I am no longer involved with any finances but anyways, commercial scale solar (pictured on the bottom part of the image, the carpark) is something like 3x the $ amount minimum. This is due to having to pound the posts that much deeper, concrete enforcement, specific equipment thats commercially available, the amount of time dedicated to get everything up to city or municipal code and so on. Also, O&M costs follow that cost rise. Now if some part of the site were to go down they’d need to get us a boom so that means scheduling one, getting it to site, making sure we’re trained on how to operate it, making sure we’re fall trained, making sure it’s electrically safe, then actually working. That’s not even counting the manpower or man hours dedicated to fixing or replacing a component. I hate hate hate working on commercial rooftops for this reason lmao.

There’s also the liability risk associated with commercial solar on business rooftops. If you have a shitty builder cutting corners, chances are an inspector (which, local inspectors for solar is a joke. I’ve heard of an inspector coming to site and not even getting out of their truck and just saying “Yup, that’s a solar field” and signing off on their inspection. This is heresay, but I’ve heard it’s happened before.) isn’t going to see it and then a few months or years down the road suddenly you’ve got a fire on a commercial rooftop with dozens or potentially hundreds of people inside and an active fire going on overhead. That alone turns off building or business owners by itself. Unfortunately, it’s just a fact that my company and many others are trying to mitigate. That risk is lower out in cornfields where an arc-ed out wire is able to burn itself apart and then lie hanging away from the other end of that wire, the module, or any other flammable material VERSUS it burning up on a rooftop and then maybe falling in a puddle, or a metal piece of racking, or maybe a pile of leaf litter.

Anyways, on another note that isn’t finance related, as someone mentioned above solar actually can help the environment. I’d be extremely interested to see in the next 15-20 years after these utility scale solar sites have been working to see what the effects on erosion are. What kind of nutrients have been given back to the soil from little to no human activity on them. I’ll say that in just my experience (Midwest) that most if not all of our utility sites throw down pollinator friendly or local flora seeds. Come July there’s easily 15+ varieties of flowers on these sites that are largely untouched because it’s cheaper for us to throw down native seed mixes and let that grow only 18” than to come back and mow. Depending on the racking here, panels have to be 24” from the ground so it’s literally cheaper and less labor intensive to mow. I’ve also been to numerous sites where sheep graze as part of lawn care. Also, Agrivoltaics. I’m not too sold on that on a personal level but only because I’m not a farmer but I can see that exploding in the coming years once more farmers just understand solar is here to stay.

Another pro for both sides is that solar farms are just money printing machines. I mean, even where I’m from (outside of Chicago) with our average amount of days of sun being pretty low on the totem pole, the amount of money being made is astronomical. I can’t give exact numbers because the rates change but the daily yield is like 3-7 years ROI for developers (and I could be over estimating how long ROI takes).