Homeowners in San Diego County have a new tool when considering the costs and benefits of installing rooftop solar panels.
The local nonprofit Center for Sustainable Energy launched a web page this week that allows residents to see how much they could save on their electrical bills based on a number of factors.
The web-based “Solar Savings Calculator” is intended to inform consumers who are considering whether to contract with a particular installation company, said Christina Machak, senior research analyst for the center.
“The value proposition for solar depends on lowering a homeowner’s monthly electricity bills,” she said. “The calculator gives a household-specific look at what homeowners can shave off their monthly utility bills in actual energy and dollar savings.”
The calculator uses location data to determine how much sunlight a particular home gets exposed to, as well as energy consumption patterns for residential customers of San Diego Gas & Electric. Users can download a detailed history of their electricity use from the utility and then upload it the center’s website.
The tool also uses updated information on the state’s net-energy-metering program, which determines how customers are compensated for the solar power they generate. In general, if ratepayers produce more electricity than they consume in a given year, they are paid a wholesale market price, which is less than the retail price, for that excess energy.
The rules were overhauled last year and could be adjusted again in the future. Once a customer installs solar panels, they are grandfathered to the current net metering rules for the next two decades.
However, SDG&E may get approval from state regulators to adjust other factors that can impact ratepayers with solar panels, such as when customer are billed for off-peak and on-peak hours. To address this, the calculator includes a tool to allow prospective consumers to better understand what their savings could look like under best and worst case scenarios.
“In general, for new customers with solar PV who primarily use electricity in the evening and early morning when the sun is not shining, shifting the on-peak period would result in less savings,” Machak said.
The calculator is customized for SDG&E customers. But given enough demand, it could be adjusted for use in other utility areas, she said.
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