In 2014, two solar energy groups published a report finding that only about 3,750 U.S. schools — out of a total of roughly 130,000 — were generating electricity from solar panels. But that number is on the rise.

According to the fourth edition of the “Brighter Future” report, released last week by the clean energy nonprofit Generation180, the number of U.S. schools using solar power has more than doubled in the last seven years, reaching roughly 8,400 by the end of 2021. These so-called “solar schools” now account for nearly 1 in 10 public, independent, and charter K-12 schools and serve more than 6 million students nationwide.

Tish Tablan, director of Generation180’s Solar for All Schools program and lead author of the report, called the number “an incredible milestone.” As some schools build new rooftop and ground-based solar arrays, others are subscribing to community solar programs. In some cases, schools with solar panels are generating enough electricity to sell it back to their communities. Since 2015, American schools’ total solar energy capacity has nearly tripled to 1,644 megawatts — enough to meet the electricity use of all the households in a city the size of Boston, Denver, or Washington, D.C.

According to Tablan, much of this growth has been enabled by third-party financing models like power purchase agreements, or PPAs. With these agreements, developers pay to install and operate solar panels, while schools buy the electric output for a predetermined amount of time. Developers benefit because the agreements allow them to take advantage of federal tax credits and provide a stable source of income.

For schools, the agreements can slash thousands of dollars off their utility bills and remove up-front costs associated with solar installation — something that the Generation180 report says has been “critical” for solar expansion beyond the most affluent school districts. As of 2021, the report finds that 47 percent of the public schools with solar power are eligible for federal Title I Schoolwide Program funding, which indicates that at least 40 percent of their students come from low-income families. (As of 2019, 57 percent of all public schools nationwide are eligible for such funding.)

Read the full article about solar power in schools by Joseph Winters at Grist.