15.72.040 Size.
A. Minimum system size may be calculated by either of two methods, prescriptive or performance.
1. Prescriptive Method. The minimum system size utilizing the prescriptive method is two watts per square foot of conditioned building area including existing, remodeled and new conditioned space. Watts are calculated by using the nameplate rating of the photovoltaic system. There are no considerations for performance such as tilt, orientation shading or tariffs.
2. Performance Method. The system sizing requirement for the performance method shall be calculated using modeling software or other methods approved by the Building Official. The total building load including conditioned and unconditioned space is calculated in kilowatt hours. The photovoltaic system annual output is calculated by factoring in system orientation, tilt, shading, local weather conditions and equipment efficiency. The photovoltaic system must offset 75 percent of the electrical load of the building on an annual basis.
B. Incentives, to be determined by the Official, shall be instituted for installations which exceed the minimum size required.
C. Methods of electrical energy production through renewable sources other than photovoltaic systems shall be considered when calculating the total requirement for any specific project.