One of the tunable parameters is the "size of your electric bill", which defaults to $150/month and maxes at $500/month -- far too low for a city hall, I should think. This is the limiting factor here, not the size of the roof. At $500/month, the recommended installation size is 765 square feet, but the total roof size is 50,171 sq feet. Only a small fraction of the roof area is being used.

This has clearly been designed for residences and not larger buildings.