As the price of solar power falls, it is moving into the mainstream, increasingly being taken up by moderate and lower income Americans.

A new report by Lawrence Berkeley National Laboratory looks at income trends among 1.4 million residential rooftop solar adopters, representing the most extensive analysis of this topic to-date. Unlike previous studies, researchers used address-specific income estimates, rather than from the Census tract of the solar homeowner, providing more precise results.

In all, about 15 percent of solar adopters nationwide fall into the lowest income category, less than $50,000 of household income per year, while another third fall into the next income range, between $50,000 and $100,000.

As shown in the figure, solar adopters (dark blue bars) are underrepresented in the lowest income bracket, which includes over 40 percent of US households. But in the next bracket, the portion of solar adopters is almost exactly proportional to the total portion of households (gray bar), as well as the portion of owner-occupied households (gold bar).

In other words, the incomes of solar-adopters skews high relative to the broader population, though less so when compared to just owner-occupied households, and also less so when compared to other households in the same local area (such as the county or census tract).

TREND OVER TIME

Solar adoption has been gradually migrating toward lower income ranges over time, reflecting the spread of U.S. solar markets. For example, households with annual incomes of less than $100,000 grew from 39 percent of solar adopters in 2010 to 48 percent in 2018, while those with incomes of more than $200,000 dropped from 26 percent to 16 percent. Similar trends are evident within most individual states and counties as well.

Overall, 18 percent of 2018 solar adopters have incomes below the national median for all households, while 30 percent are below the national median for owner-occupied households, and 38 percent are below the median income for owner-occupied households in the same Census tract.

BY LOCATION

Solar adoption varies by state and local markets. In Louisiana, almost 80 percent of solar adopters have annual incomes of less than $100,000. The portion in Wisconsin and Vermont is over 60 percent.

Relative to local income levels, more than half of solar adopters in Connecticut, Louisiana, and New Jersey, plus 42 counties, have incomes below the local median for owner-occupied households. In most states, between a quarter and a half of solar adopters have incomes below the state median.

To see an interactive tool with income data by state and county, click on the image.

Some local variations are driven by policies and programs that specifically encourage adoption by low-income households. State and local governments may offer extra incentives or financing for income-qualified buyers, for example.

Lastly, solar adopters tend to have higher home values and credit scores, relative to the broader population. Among all 2018 solar adopters, only 27 percent have home values below their respective county median, while 35 percent have credit scores below the median. As with the income trends, however, these numbers have been rising over time as adoption rates increase among households with below-median home values and credit scores.

The report, published in slide-deck form along with an accompanying set of interactive data visualizations, is available at solardemographics.lbl.gov.

The authors will also host a webinar highlighting key findings from this study on March 10 at 2ET / 11PT. Register for the webinar here.

Funding for this research was provided by the U.S. Department of Energy Solar Energy Technologies Office.