UPDATE: The proposal has been approved and the lights will be installed before The Big Chill in December.
When Michigan Stadium's renovation was taking place over the last few years, one of the things many people wondered about was why no lights were being installed. After all, there is usually at least a game or two every October and November that requires temporary lights to be brought in because of a late kickoff, so why not just put in permanent lights?
I believe the reason no permanent lights were installed is because the TV networks pick up the cost for the temporary ones whenever they are needed. The renovation, which was conceived under Bill Martin, came at a time when there were no immediate plans to ever play at night, so there just wasn't a big need.
When Dave Brandon became the athletic director, however, one of the first things he did was schedule a night game at the Big House. With more night games likely in the coming years and the Michigan-Michigan State hockey game at Michigan Stadium set to finish at night, there is now a need for permanent lights, which is why there are plans for them to be installed this fall, if approved by the U-M Board of Regents.
“It is expected that the demands for field lighting will continue to increase over time,” the memo says. “This project will provide permanently-mounted lighting at the stadium, with the benefits of increased quality of illumination, greater reliability, and improved aesthetics. The scope of this project includes the architectural, mechanical and electrical work necessary to accomplish these improvements.”
The temporary lights got the job done, but they never were all that bright. New lights that are permanent should light up the stadium much more than the temporary ones, which is why there is a need for them with the night game against ND next year and the hockey game later this year. Plus, as the quote above states, demands for field lighting are expected to increase over time, indicating that more night games are in the works.
It's unknown exactly where the lights will go, but I believe the stadium renovation made it possible for permanent lights to be installed on top of the structures that house the press box and luxury suites. That is where the temporary lights go, so I'd imagine the permanent ones will be installed on top of the new structures.