When I plan to buy a house I'll seriously consider installing solar, but id almost want to tear down any installation forced on by the city. If it's your property it should be up to you to consider what you want to add to your domicile. Maybe I don't want the upfront cost of solar, or maybe I planned on other renewables.
Put solar on all your city buses, put solar on all city buildings, etc. Don't force solar on homeowners who never wanted it.