In 2013 The City of Sebastopol became the second U.S. city to require photovoltaics (PV) to be installed on new buildings. The ordinance applies to all new commercial and residential buildings, and additions to existing commercial and residential buildings. The ordinance defines additions to commercial buildings as any addition that increases the square footage by 1,800 or greater and all remodels, alterations or repairs of more than 50% of the structure. The ordinance defines additions to residential buildings as any addition that increases the square footage by 75% or greater and all remodels, alterations or repairs of more than 75% of the structure.
Minimum system size may be calculated by either of two methods, prescriptive or performance. Buildings using the prescriptive method must install 2 watts per square foot of conditioned building area including existing, remodeled and new conditioned space. Buildings using the performance method must use modeling software or other methods approved by the official to demonstrate that the system installed will meet 75% of the building's annual electricity load.
The Building Official may exempt buildings from the requirement and impose reasonable conditions in lieu of full compliance if the Official determines that there are practical difficulties involved in meeting the requirement. The City Council may establish an in lieu fee as an acceptable alternative for full
Owners of multiple properties may install a single PV system meeting the aggregate energy generation requirement for all owned properties which require compliance with the requirement.