Sukreet,

I haven't seen much on courthouses, but offices are pretty well covered in
the literature. Here are links to a couple of relevant studies:

Assessment of the Technical Potential for Achieving Net Zero-Energy
Buildings in the Commercial
Sectoris a modeling study
by NREL.
A Look at the Costs and Features of Zero Energy Commercial
Buildingsis
a report by the New Buildings Institute with a good collection of case
studies.

Hope this helps as a starter; I'm surprised no one else has chimed in yet...

Sam Brunswick