There is an excellent post about the viability of solar power at data centers by James Hamilton.
The follow up discussion in the comments are great, definitely worth reading. Power density at a data center versus other spaces (homes, offices, retail, etc.) is what really seems to make the math so bad. I am curious to see if there is anything significant to the idea of solar panels on the roof also helping reduce peak heat exposure.
I love seeing attempts at figuring out the math behind what would be most efficient instead of the most placating.