Falling installation costs have facilitated American schools’ switch to solar, allowing them to invest in education. Since 2014, the number of K-12 schools employing solar has nearly doubled to 5,489 schools, according to a new report.

The report, by The Solar Foundation, Generation 180, and the Solar Energy Industries Association (SEIA), says the dramatic growth in solar school adoption is being driven by rapidly declining installation costs. The average price of a solar school installation has dropped 67 percent in the last 10 years, falling 19 percent in 2016 alone.

Nearly 4 million students in the U.S. attend schools with solar power, with a combined capacity of 910 megawatts (MW), an increase of 86 percent over 2014. The amount of electricity these schools produce annually, at 1.4 million megawatt-hours, is enough to power over 190,000 homes.

The report, Brighter Future: A Study on Solar in U.S. Schools, 2nd Edition, is the most comprehensive study to date on solar at K-12 schools nationwide. As a follow-up to the first study released in 2014, this report captures the accelerating trends of solar adoption in U.S. schools.

California leads the nation in the number of solar schools by state, with 1,946 solar schools and a 489 MW capacity, followed by New Jersey, Arizona, Massachusetts, and New York. Nevada has the highest adoption rate, with 23 percent of schools using solar energy statewide. Arizona has the most solar school capacity on a per capita basis, at 86 watts per student.

“Solar can help school districts save millions on electricity bills, freeing up funds for additional teachers, improved facilities, and enhanced academic and extracurricular programs,” said Andrea Luecke, president and executive director of The Solar Foundation. “In addition to cost savings, solar energy installations can serve as hands-on STEM (science, technology, engineering and math) laboratories for students to learn about clean energy from the sun.”

At the same time that costs are going down, schools have more financing options that minimize up-front investment. In recent years, most schools have financed their solar installations through power purchase agreements (PPAs), in which a third-party finances, builds, owns and maintains the system. This allows schools and districts to purchase solar with very little initial cost. Within the last three years, nearly 90 percent of the schools for which data is available used a PPA to install solar.

“There’s a reason solar is spreading so quickly across America’s school districts, and it’s pretty simple — when schools go solar, the entire community benefits,” said Abigail Ross Hopper, SEIA’s president and CEO. “By switching to solar energy, schools immediately see their electric bills go down, leaving more money for learning. Plus, what teacher wouldn’t want a life lesson in science and conservation right there on school grounds? It’s a win all the way around.”

The Brighter Future report includes several in-depth case studies that demonstrate how schools across the United States have gone through the process of installing solar. These systems are going up on school rooftops, parking lot structures and offsite. The report identifies numerous cases where schools expect to save millions of dollars in electricity bills over the next two to three decades, helping them balance the budget and pay for educational expenses. Some of the solar projects were initiated by students themselves, while others got started at the administrative level or were part of a school’s capital improvement campaign.