So, I was working for a wind energy company for a few years and will give you my insight the best I can (Disclaimer: no promises that I have any idea of what I'm talking about). In our company we had both a development side and an operations side. I was part of the development side and when we started researching drone usage it was more for site suitability and site visits for field verification during the planning phase. We would always end up in a time crunch waiting for the survey data from the contractors during the site design and so we weren't able to get a good and accurate "bird's eye" view while we were waiting. I had proposed drones as a way to get a jump on the survey data and have better inputs. You can imagine trying to design a huge wind farm based on bad county parcel data, the latest imagery you can find (usually Google Earth), and a few site visits by a team of just a few people. A drone would have helped that immensely and prevented a few very large headaches because we had no idea something was there when we should have known.
As for once the wind farm is built and in operation I wasn't as much a part (hence the longer response above), but I did see that they were starting to use them for quick visual inspections for damage after storms (I don't think they needed 3D models, but just a set of eyes on any damage they couldn't see from the ground.) Also, they used drone imagery in some promotional videos, but those jobs were usually contracted out to full blown production companies that did the aerial shots along with interviews and the rest of the 3-ring circus.
Of course this is all to say that it probably depends on the site manager and what they want to see/get in terms of information on a daily basis as well as their comfort of having a drone on site. I am finding more people that I wouldn't expect leveraging technology like drones, but there are a lot rural wind farms in operation that were built way before it got this easy, so they may be behind the curve still and would prefer someone else to help out.
Either way, I don't think it can hurt to at least start checking with the guys working out there day to day and see what they are doing. If anything I am also curious as to how much it has taken off (pun intended I guess) and how receptive they are to the idea.
I do love the site of the huge turbines spinning in the wind! I'm jealous as we don't have any active ones in Virginia yet, closest is probably West Virginia, although one just got built in North Carolina last year or so.
Good luck!