Across the country, shopping malls, schools, factories and other large, non-residential buildings bask in the sun—a powerful, and too often wasted, source of electricity that can serve the neighborhoods that surround them.
Installing solar panels on these sprawling rooftops could provide one-fifth of the power needed by disadvantaged communities, bringing renewable energy to people who can least afford it, according to a study by Stanford University. Although such power-sharing arrangements do exist, the research found that marginalized neighborhoods generate almost 40 percent less electricity than wealthy ones. “We were amazed to see that there was still such a big difference,” said Moritz Wussow, a data and climate scientist and the study’s lead author.
This imbalance, often called the solar equity gap, is even more pronounced in the number of home installations. Placing solar arrays on top of large commercial buildings can bring renewable energy to tenants while also helping homeowners who can’t afford the technology’s high upfront costs. Previous research by Wussow’s collaborators found that affluent households are more likely to take advantage of tax credits and rebates designed to make solar power more affordable. With Solar for All, a federal program funded by the Inflation Reduction Act, ready to issue statements $7 billion to create fairer access to clean energy, the study shows that utilizing commercial rooftops can be an effective way to reach two-thirds of the nation’s disadvantaged communities and begin to close that gap.
“The renewable energy transition is one of the big pillars of where the government wants to spend money,” Wussow said. “Our research is supposed to contribute to reducing the equity gap, and to give an idea of how this can be achieved.”
With the help of DeepSolarUsing Stanford’s AI-powered database of satellite images, the study counted the number of photovoltaic panels on large rooftops, at least 1,000 square feet in size, across the US. To help its research more easily inform policy, it defined the prevalence of these settlements in census tracts as disadvantaged by the federal Justice 40 environmental justice initiative. These areas, which should be low income and have a second environmental burden, such as pollution, make up about a third of the census tracts. The researchers then calculated the cost of generating solar power on non-residential buildings in those areas and found that even in states like Alaska, where the sun disappears for almost two months each year, the cost per kilowatt would still be cheaper than the local utility rate. If businesses generate their own energy and share it, the results show that residents of the surrounding neighborhoods can save money and meet at least 20 percent of their annual power needs.
Despite prevailing equity gaps, community solar projects have been for in a decade. “I like to think of it as a model, a billing mechanism, where people, whether they own or rent, can participate in the solar transition,” said Matthew Popkin, a U.S. program manager at RMI, a non -profit dedicated to sustainability research. Most community solar systems rely on subscriptions, where homes connected to a local solar array pay for a share of the energy. Such programs help neighborhoods in cities of Denver on Washington DC, save money and ditch fossil fuels. “There is no one-size-fits-all approach, there is no model that will nail it for every single community, or an entire city,” Popkin said. “More creativity will probably help expand it further.”
Boston, a city with little open space but many rooftops, can expect community solar on commercial buildings to expand soon. The Boston Solar Community Cooperative, which was launched this March, will begin its mission to bring clean energy to underprivileged households with an 81-kilowatt solar system atop a grocery store in Dorchester, one of the city’s lowest-income neighborhoods. Gregory King, president of the cooperative, said the project is only possible because of solar tax credits provided by the Inflation Reduction Act. “The idea behind the model is really to create community empowerment,” he says. “And we need to create more and more, especially rooftop solar, in an urban environment like Boston.”
Recent changes in how utilities buy solar energy back from homes, a process called net metering let residential installations decline. But with Solar for All funding about to start pouring into states so soon July, experts like Popkin say these new resources could shape the next wave of community solar power. “The biggest unknown we have right now is what some of those exact funding structures are going to look like,” he said, but inclusive planning will be key. As communities across the US race to seize clean energy benefits, incentivizing businesses to go solar and share the bounty can give everyone a brighter future.
