A report recently published in the journal Nature Sustainability outlines large racial and ethnic disparities in installations of rooftop solar.

Researchers with Tufts University and the University of California, Berkeley found that census tracts that are over 50 percent black or Hispanic have “significantly less” rooftop solar installations than census tracts with no majority or that are majority white — pointing to the equity implications of an unevenly developing solar industry. 

“As renewable energy becomes more and more prominent, there’s a lot of hope that energy injustices that have been suffered in the past…will be overcome,” said Deborah Sunter, an assistant professor of mechanical engineering at Tufts and the lead author of the study. “When it comes to rooftop solar, there are a lot of economic benefits…and so unlike the fossil fuel industry, where energy injustice was attributed to exposure to negative consequences like pollution, with rooftop PV the injustice is more that certain communities are missing out on these economic benefits.”

Another of the study's authors, Daniel Kammen, a professor of energy at UC Berkeley and a former science envoy for the U.S. State Department, said the results should help "build a better and more inclusive energy transition,” with the recognition that "lack of access or a lack of outreach to all segments of society can dramatically weaken the social benefit" of solar.

Solar installations trail in communities of color

The study relied on data from Google’s Project Sunroof, which shows the potential for rooftop PV on 60 million buildings throughout the United States and accounts for 58 percent of the national potential for energy generation from rooftop solar. 

According to the results, in census tracts with the same median household income, communities with over 50 percent black residents have 69 percent less rooftop solar installed than tracts with no racial or ethnic majority. Majority Hispanic census tracts had 30 percent less installed. Majority Asian census tracts had on average 2 percent less solar installed than non-majority tracts.

Majority white communities, by contrast, had 21 percent more rooftop solar installed than tracts with no racial or ethnic majority.

Relationship Between Household Income and Rooftop PV Installation by Race and Ethnicity

Source: Nature Sustainability 

The results are equally stark when accounting for home ownership. In census tracts with the same levels of home ownership, majority black census tracts had 61 percent less solar installed than tracts with no racial or ethnic majority, and majority Hispanic census tracts had 45 percent less. White majority census tracts had 37 percent more installed than no majority tracts.

Looking for "seed" customers

The authors also noted that PV installations often result in a feedback loop: When a few residents in a community get solar, known as “seed” customers, it compels others to join. Communities without those first-mover customers show delayed solar adoption. 

Majority black communities show disproportionately low “seeding,” according to the study. Among the census groups that the study looked at, 47 percent of majority black census tracts had no solar installations at all. That's well above the 24 percent of majority Hispanic census tracts without any solar installations — the census group with the next highest percentage of the population without solar PV. 

But the authors note that when seeding does occur in communities of color, deployment “significantly increases” compared to other racial or ethnic groups.

Percentages of Each Census Tract With and Without Existing Rooftop Photovoltaic Installations

Source: Nature Sustainability 

In addition to hypothesizing that seeding may play a role in lower levels of deployment in communities of color, researchers suggested that the whiteness of the solar industry’s workforce could be hurting deployment in those communities.

The Solar Foundation’s 2017 U.S. Solar Industry Diversity Study found that the solar industry was 74 percent white. White people also held between 78 percent and 90 percent of management and senior executive positions at solar companies. And only 27 percent of employer respondents to the foundation’s survey said they formally track employee diversity. 

Making the solar industry more inclusive

Melanie Santiago-Mosier, Vote Solar’s program director of access and equity, said the Nature report adds to the data showing the solar industry that it needs to improve.

“A significant step toward serving all communities across the country is making sure that our industry internally is very inclusive,” said Santiago-Mosier.

But she also said the industry, along with partners, is working to remedy its abysmal representation numbers. She pointed to initiatives like the Solar Equity Initiative launched last year by the NAACP, with partner support from groups like Vote Solar and the Solar Energy Industries Association (SEIA). That program aims to connect communities of color and low-income communities with solar infrastructure and provide solar job training.

Last year, the Historically Black Colleges and Universities Community Development Action Coalition and SEIA also signed an agreement to work together on recruiting more students into the industry from historically black colleges and universities. In 2016, SEIA also published a “best practices” guide to boost diversity and inclusion in hiring and recruitment.  

Santiago-Mosier also said it’s essential for the industry to build partnerships on the ground with community organizations in underserved communities.

That’s especially important because communities of color have been and continue to be disproportionately impacted by pollution from fossil fuels. Grassroots organizations in these communities have long fought against the unequal environmental impacts they’ve faced. Because “this is an industry that was founded on the desire to do better,” Santiago-Mosier said solar must to do its part to mitigate those impacts. 

“The promise of solar energy is one of lower and stabilized utility bills, investments in local economies and healthier communities,” said Santiago-Mosier. “The industry should…embrace the opportunity to use this information, use the data that’s out there to say: Where should we be going? Where should we be deploying solar and how should we be growing? […] The opportunity is there for the solar industry to really take a look at how it is serving its customers.”

Both Santiago-Mosier and Sunter said that aside from the study’s clear justice implications, the industry should also recognize the opportunity presented in communities of color where solar penetration is low. Increasing adoption in all areas of demand is the only way to grow markets to their full potential. 

“Ultimately, if [the industry] wants to maximize adoption, they’re going to have to understand and address what these challenges and issues are that are resulting in minority communities basically being left out of this growth,” said Sunter. “If there isn’t intervention, it’s likely this disparity could continue to grow.”