Shadows on the cathedral: Solar access laws in a different light

Unprecedented growth in rooftop solar energy development is drawing increased attention to the issue of solar access. To operate effectively, solar panels require unshaded access to the sun's rays dur ing peak sunlight hours. Some landowners are reluctant to invest in rooftop solar panels because they fear that a neighbor will erect a structure or grow a tree on nearby property that shades their panels. Existing statutory approaches to protecting solar access for such landowners vary widely across jurisdictions, and some approaches ignore the airspace rights of neighbors. Which rule regime for solar access protection best promotes the efficient allocation of scarce airspace within the constraints of existing law? This Article applies Calabresi and Melamed's "Cathedral" framework of property rules and liability rules to compare and analyze existing solar access laws and to eval uate a model solar access statute recently drafted under funding from the United States Department of Energy. Surprisingly, the Article concludes that a statute implementing the Cathedral model's seldomused "Rule Four" is best suited for addressing solar access conflicts.