2015-01-08 09:04:14 -0500
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Solar for multi-tenant buildings is certainly a viable option. In fact California incentivizes landlords to install solar on their multi-family homes through its MASH (Multifamily Affordable Solar Housing) program: http://www.cpuc.ca.gov/PUC/energy/Solar/mash.htm.
If a solar array is installed, the power produced can either be used to service the common areas (halls, lobby, etc) or distributed to individual apartments (and the saving shared).
In the case of power in the common areas, the setup would be pretty much the same as installing a system on a single-family home - the power would flow from the panels into any lights, etc used in the common areas. Any excess power would flow into the grid and credited to the landlord's bill via Net Metering (http://blog.energysage.com/net-metering-the-back-and-forth-of-solar-power-systems/). The savings could be shared with the tenants in some way - perhaps through lowered service fees or rents.
If you're hoping to get the benefits of the solar electricity distributed to the individual apartments, you'll want to check if your state has a Virtual Net Metering policy. This would allow you to virtually distribute the solar power and its benefits to all the tenants or condo owners in the building - instead of having to install multiple small systems for each apartment.
http://blog.energysage.com/wp-content/uploads/2015/01/Virtual-Net-metering.png (Virtual Net Metering)
Renewable Energy World did a great write-up on California's MASH program (which you can read here: http://www.renewableenergyworld.com/rea/news/article/2013/08/california-solar-energy-apartments-virtual-net-metering-allows-energy-savings-one-tenant-at-a-time). You'll want to check to see what the policy climate for this sort of thing is like for your state, however.
As far as convincing the other people in your building is concerned: The case for going solar is only getting stronger as time goes by in the US. Get some solar quotes from installers in your area (https://www.energysage.com/market-intro/) and see what they can do for you, and if it looks like it's a good investment (or in the case of a solar lease (https://www.energysage.com/solar/financing/solar-leases-and-solar-ppas), a good way to save money from the outset), then take them to your fellow residents. With any luck, the numbers will speak for themselves.
Community Solar: You might also want to look into Community Solar options in your state. We've published some research on the topic of Community Solar / Community Solar Gardens (which you can read here: http://www.energysage.com/solar/community-solar/community-solar-power-explained). Basically, Community Solar programs allow you to partake in the benefits of solar energy even if you don't have a solar system on your roof - the electricity produced by the solar array is instead virtually credited to your bill. This would mean you could go solar without having to convince your condo association to get on board as well!
We've also done some research into where such programs are currently available, which you can read more about here: http://blog.energysage.com/community-solar-gardens-sharing-the-sun/.
http://blog.energysage.com/wp-content/uploads/2014/11/6_CS_map_states-to-watch.png (Community Solar Gardens in your state)