One of the nice things about solar rebate programs — beyond the fact that they help reduce the cost of solar installation — is that they can provide a trove of interesting solar-related data.

See, in order to ensure that you receive state- or utility-sponsored solar rebate funds, your solar installer will need to file an application stating (among other things) the size and per-watt cost of your solar energy system. These numbers from across the state can then be aggregated to provide a snapshot of the solar energy market: who’s installing solar panels, where they’re being installed and at what cost.

In California, this data aggregation is carried out by Go Solar California, a joint endeavor of the California Public Utilities Commission and the California Energy Commission. The group maintains a useful database of statewide solar power statistics. We ran a quick query to see which California counties lead the state in terms of the number of residential solar energy systems.

As you can see, San Diego county is numero uno, with nearly 25 megawatts (MW) in installed residential solar power. Los Angeles county — at least the portion served by Southern California Edison (SCE) comes in second with about 15 MWs worth of solar home energy systems. Then we’ve got Santa Clara, Riverside, Orange and on down the line. Taken together, these counties represent 48,883 residential solar rebate applications that have either been accepted or are currently awaiting approval.

If you’re interested in learning more about things like solar energy system size and solar cost in California, be sure to check out Go Solar California’s database!