Most of the water used in Arizona is for agriculture, but another common usage is for cooling natural gas, coal, and nuclear power plants. Obviously, operating rooftop solar power does not require such water use.

“He said that if Arizonans increased their use of rooftop solar power to 20 percent of the energy supply from the 1 percent it represents today, the state could save 15 billion gallons of water a year. That’s enough water to serve 90,000 homes, or the population of Chandler,” reported Arizona Central. The article was referencing former Arizona Department of Water Resources Director Herbert Guenther, who was hired by the Alliance for Solar Choice. Currently, the solar power installed in Arizona is saving about 750 million gallons of water a year. (Of course, adding that much solar would also reduce climate change emissions and air pollution.)

Arizona gets about two-thirds of its electricity from nuclear and coal, with natural gas providing about 25%. Hydropower supplies most of the rest, and there is a little solar power. The Arizona Renewable Portfolio Standard requires the state to produce 15% of its electricity from renewables. The Hoover and Glen Canyon dams produce most of the hydropower.

So, could Arizona get enough solar power capacity to generate 20% of its electricity and save 15 billion gallons of water each year? A report from Environment Arizona says it could get to 25%, “Solar PV capacity in Arizona increased at a rate of 142 percent per year from 2010 to 2013. If solar PV installations continue to increase at just one-seventh of that rate (20 percent) annually between 2013 and 2025, Arizona would have enough solar energy to generate 25 percent of its electricity.”

According to SEIA, Arizona has about 2,143 MW of solar power installed currently, which ranks it no.2 in the US only behind California. Politics seems to have been one of the main barriers to expanding solar more aggressively in Arizona, not any technological barriers. Environment Arizona has written that Arizona could have enough solar power to generate well over 300 times as much electricity as it consumes.

Mai Linh (Cleantechnica)