County Debuts New Solar Mapping Program

Supervisor Don Knabe, Chairman of the Board of Supervisors, announced a new Internet-based technology today that will allow businesses and homeowners to determine if their properties are good candidates for solar power.

The new website, available at went live today. It is the largest solar map in terms of geographic area in the world, covering 3,000 square miles. The program uses roof size, pitch and shading from nearby trees, buildings and mountains to provide a building’s solar potential and the potential value of installing solar panels.

By typing in an address, a person will learn the property’s roof size, area suitable for solar panels, electricity produced, electricity savings, carbon reduction, nearby solar installations and case studies, available rebates from utility companies, and information about installers.

The level of detail provided means that residents and solar installers do not need to go up on every roof to see if it can support solar, saving time and money. Solar installers will be able to give more detailed estimates based on specific situations, but the solar portal provides generally accurate guidelines of what can be expected. The ultimate goal is to make the website a one-stop solar shop for residents and businesses.

The solar website, developed at a cost of $93,500, was generated from high-resolution imagery and elevation information acquired in 2006 which included roof-top and ground elevation every five feet. It calculates and ranks incoming solar radiation every 25 square feet, using roof pitch, orientation, and shading from surrounding structures and trees to provide the best estimate possible.

The project will be of great benefit to the County itself, as it includes high resolution – three-dimensional modeling of 800 County buildings. These detailed analyses will be used to evaluate and implement cost-effective installations, including solar power and solar water heaters. The County is a major electricity user, with facilities spread over a wide geography, operating in more than 3,000 buildings that comprise more than 60 million square feet.

The County is also developing a program that would assist homeowners and businesses in financing solar panels. On April 14 the Board of Supervisors approved Supervisor Ridley-Thomas’ motion to create by July a program that would allow property owners to finance energy-efficiency upgrades by borrowing money from the County and paying it back through their property tax bills.