Greg Barron-Gafford’s research team began growing crops beneath 9-foot solar arrays at the University of Arizona’s Biosphere 2 in 2017.

PHOENIX — The population is rising, water is scarcer and demand for energy is growing.

Land developers in central Arizona have multiple issues to think about when planning for the future. But two Arizona State University researchers think there’s a solution to solving all these problems.

It’s called “agrivoltaics,” a type of dual use of agricultural land where farmers grow crops under rows of solar panels.

Farmers in Japan and Italy have already caught on to the innovative idea, and Martin Pasqualetti, a professor at the ASU School of Geographical Sciences and Urban Planning, believes it’s an efficient method to preserving farmland as metropolitan Phoenix continues to sprawl out into rural areas.

He and Debaleena Majumdar, an ASU doctoral student, released a research paper last fall that made the pitch for adopting agrivoltaics in Arizona.

They say Arizona’s current model of continuing to build on the edges of Phoenix is not sustainable or healthy, as farmland in Pinal County could continue to give way to developers.

The researchers believe making a dual use of existing farmland will be beneficial to both growers and consumers. They’ve reviewed other studies that found growing crops under solar panels resulted in savings for water use.

A 2013 study published in the European Journal of Agronomy found that lettuce heads and cucumbers grown under solar panels resulted in a 14 to 29 percent reduction in evapotranspiration.

The solar panels could also become an additional revenue source for farmers, if utility companies compensate farmers for each unit of energy generated on their land. Pasqualetti and Majumdar found by analyzing existing farms in Pinal County that many could earn back the value of their land within two to four years of utilizing an agrivoltaic system.

“The additional income a farmer would make by installing an agrivoltaic system would be in most cases more than the sale price of the agriculture land itself,” the research paper stated.

Other studies on agrivoltaic systems in foreign countries concluded the model resulted in better ecological performance, a boost in crop production and better use of light and space.

University of Arizona researchers have been experimenting with agrivoltaic models in recent years at Biosphere 2, a research facility located in southern Pinal County. The researchers have been studying whether growing plants underneath solar panels will keep the panels from overheating, since the plants absorb carbon and emit water to cool the environment.

And if the utility industry decides to continue producing more solar energy, then the companies will need more land in Arizona to build panels.

Pasqualetti said if the ballot measure Proposition 127 were to pass in November, then there would be a greater demand for space to generate more renewable energy. The initiative would require utility companies to sell increasing amounts of renewable energy.

The ASU researchers said agrivoltaic systems allude to a bigger question about urban planning — what type of cities do people want in the future?

In their minds, solar panels could protect rural farmland from being gobbled up, thus moving Arizona’s growing population closer to the metropolitan areas.