Concentrated photovoltaic systems using III-V semiconductor multi-junction solar cells provide an attractive solution for electrical power generation integrated onto buildings. Concentration photovoltaics hold the potential to significantly reduce the cost of energy generation, both through the smaller amount of semiconductor material they require and their increased energy efficiency. These devices are spectrally sensitive, and therefore must be engineered to balance the available light by tailoring the properties of each junction, the front electrode, the antireflection coating, and the optics. The high efficiency of these cells permits the highest power density available using any type of solar cell, with the potential to displace 100% of the electrical demand of an average 1-3 floor building in several Canadian cities under ideal conditions. The photovoltaic system planned for installation at the University of Ottawa is also described.