Some changes already are underway.
Arizona Public Service Co. in March increased its customer charge, a move it said was needed to fund fixed costs fully as more customers add solar. California utilities have lobbied for changes that included higher fees and a cap on the number of people who could use net metering.
The Golden State earlier this month enacted A.B, 327, a new law that imposes a rewrite of electricity rates. It protects net metering for the next few years (Greenwire, Oct. 8). But in 2015, the CPUC is ordered to retool net metering, creating a new program that will be "based on electrical system costs and benefits to nonparticipating rate payers."
The Center for American Progress examined solar installation data in California, Arizona and New Jersey, states that have issued subsidies or tax credits for rooftop solar adoption. Databases from those states provided the income information. The Center for American Progress then looked at census findings to pull median incomes by neighborhood.
The CAP analysis found that in Arizona, 80 percent of rooftop solar installations occurred in neighborhoods with annual incomes ranging from $40,000 to $90,000. In California, 67 percent of adoptions fell within that income band, and in New Jersey, it was 64 percent.
In New Jersey, households with incomes greater than $90,000 made up 32 percent of installations, while that group was 29 percent in California and 13 percent in Arizona.
In the Arizona, the report said, the highest number of installations occurred in ZIP codes with median incomes ranging from $40,000 to $50,000. In California and New Jersey, homeowners with median incomes ranging from $70,000 to $80,000 have installed the most photovoltaic systems.
The income data conflicted somewhat with the CPUC report out of California. That said that since 1999, customers with net energy metering "have an average median household income" of $91,210, compared to the state median income of $54,283 and median income in the investor-owned utility service territories of $67,821. The author of that report did not immediately respond to an email asking for clarification on the definition of average median household income.
Hernandez said that she didn't know what data the CPUC report had looked at, so she wasn't able to explain why her results differed. The CAP report looked at information that is part of the California Solar Initiative, or CSI, the solar rebate program offered to customers of three investor-owned utilities: PG&E, SCE and San Diego Gas & Electric.
There's been a shift over time in the income ranges that are adding solar, the CAP report said.
"While it is true that the wealthy are generally the first adopters of new technologies, our research suggests that solar technology has moved beyond the early adopter phenomenon and onto more widespread installation by the middle class," it said.
The most growth in adoptions from 2011 to 2012 came in median incomes ranging from $40,000 to $50,000 in both Arizona and California and $30,000 to $40,000 in New Jersey, it said.
The CAP analysis also found that in Arizona and New Jersey, solar installations are spread evenly across households incomes by ZIP code. In California, the distribution "is the most skewed toward the upper income brackets," it said.
The income issue aside, solar provides benefits to all rate payers, Hernandez said, including avoiding the costs of new power plants and fuel purchases in the future. In addition, she said, the power is clean, with no carbon emissions.
However, PG&E in its comments on the CPUC draft report on net metering said that there are added expenses with the growth in locally based renewable power, also known as distributed generation. Those include "incremental distribution upgrade and integration costs," PG&E wrote.