A recent story about a homeowner in Largo, FL casts a shadow on what happens if a neighbor’s trees shade your roof (ref: http://www.tampabay.com/news/business/energy/solar-powered-largo-homeowners-fights-neighbors-trees-gains-little-ground/1231054).
In Florida, we do not have particularly strong solar access laws with regards to shading. If your neighbor builds a second story or plants a tree that shades your solar panels, you are most likely out of luck. But that does not mean you can’t install solar panels and see benefits!
In the past, shading a single panel, or even part of a panel in a solar array could have devastating performance impacts. Today we have access to technologies that make solar arrays more shade tolerant. On of those technologies is the microinverter, which converts sunlight to usable household AC power on a panel by panel basis right on the roof. If part of your solar array is shaded, the unshaded panels will continue to perform.
Keep in mind that the sun moves from the east to the the west horizon each day and rises to a varying height in the sky each day dependent on the time of year. Shading may not have the impact you think on a solar array. The best thing to do is have you solar professional do a shading analysis to estimate the impact of an object between your property and the sun throughout the year. Early morning and late afternoon shade typically have a negligible effect on the overall production of a solar energy system.
If you want to learn more about solar access laws, here are some additional resources:
Solar ABCs guide on solar access laws in the US: http://www.solarabcs.org/about/publications/reports/solar-access/pdfs/Solaraccess-full.pdf
Database of State Incentives for Renewables and Efficiency (DSIRE): http://www.dsireusa.org/incentives/incentive.cfm?Incentive_Code=FL01R&re=1&ee=1