Water crises pose the no. 1 risk for the planet over the next 10 years, according to the World Economic Forum’s Global Risks Report 2016.

This may be a boon for rooftop solar power, which uses significantly less water compared to other types of electricity.

California, for example, still experiencing severe drought despite El Niño, uses 4.64 gallons of water per kilowatt-hour of electricity, according to the National Renewable Energy Laboratory. Photovoltaic (PV) solar uses 0.03 gallons per kilowatt-hour.

On the other end of the water-use spectrum: NREL says concentrated solar power, which uses mirrors to concentrate solar energy to power steam turbines, and coal facilities with carbon capture and sequestration capabilities are the biggest water hogs.

Because of its water savings, PV solar is increasingly being considered by municipalities as a drought strategy, says renewable energy company SunEdison.

Earlier this month SunEdison signed a solar power purchase agreement with Stockton East Water District in Northern California. SunEdison plans to install 2.2 megawatts on the water district’s property. By going solar, the district expects to save more than $9.5 million on energy costs over the next 20 years and 20 million gallons of water annually.

“Solar is a great way to save water,” says Sam Youneszadeh, SunEdison’s regional general manager of its Western US solar business. “By going solar, we’re able to reduce water use by 99 percent.”

Youneszadeh says SunEdison has installed solar at more than 1,000 locations in the US, saving more than 20 billion gallons of water in the process.

With SunEdison’s solar power purchase agreement, the water district doesn’t pay any up-front cost. SunEdison installs, owns and operates each system while the district buys the solar electricity at lower rates than offered by the local utility.

The solar systems are expected to generate enough energy to offset about 50 percent of the electricity used at the facility. The system also avoids the emission of more than 50 million pounds of carbon dioxide over 20 years.

SunEdison plans to complete the solar system this year.

The US has slightly more than 20,000 megawatts of solar generating capacity and nearly half of that is located in California, according to the US Energy Information Administration.

While solar power still makes up less than 2 percent of the total US electric generating capacity — utility-scale systems make up about 1.1 percent while distributed solar, on rooftops of homes and businesses, provide another 0.8 percent — the US Energy Information Administration expects solar to grow over the next couple years.

According to EIA forecasts, utility-scale solar capacity will increase by about 80 percent (10 GW) between the end of 2015 and the end of 2017, with 4.1 GW of new capacity being built in California.

“Our municipal customers typically weigh the benefits of going solar both financially and environmentally, which includes looking at water savings,” Youneszadeh says. As water scarcity grows on a global scale, solar will likely become an even more attractive option.