Matthew:
Before you make a decision on your facility lighting check the website of DayStar
http://daystarskylightsystem.com/.
I work with maintenance facilities all over the country and found this little Amish company that manufactures these skylights. I was blow-away at the light they generate even on a partly cloudy day, without electrical lighting. You'll still have to have supplemental lighting for nighttime use and very cloudy conditions. The system can be designed to work with light sensors and turn on banks of tubes as needed, (two or all four tubes in a fixture). The payback is relatively short and if you have a metal building the system can be installed in-house.
It's worth a look, good luck,
Mike