The Architecture Review Committee (ARC) got an inquiry about the possiblity of mounting solar vertically on south-facing walls (without windows). This could be a sheer flush-mounted solar PV array immediately against the wall. The PVs would not produce as much energy as a roof-top array, but there could be fewer issues with rooftop penetrations, etc. The ARC noted that there is not a specific policy about this idea yet, and they would willing to work with the idea on installation on a case by case, building by building basis, at least until there is a comprehensive policy in place.
For a given capacity of PV modules, a vertical wall will harvest 78% of the energy that a flat roof would, and 67% of the energy that could be harvested at a 40 degree tilt. While this is not ideal, the costs may be lower and the maintenance and roof loading concerns would not pertain. Two possible candidates are the south wall of NSRC (which has no windows in the "central" part) and the south facade of the Tryon Festival Theater in Krannert, which is actually somewhat tilted