This windswept desert community is full of clean energy supporters including Suzanne Rebich, an airline pilot who recently topped her house with 36 solar panels. About 200 homes generate their own solar energy and a quarter of the local electricity supply comes from hydroelectric power.

All the same, many here are dead set against a planned solar plant atop the Mormon Mesa, which overlooks this valley 50 miles northeast of Las Vegas. Slated to be the biggest solar plant in the U.S., the Battle Born Solar Project by California-based Arevia Power would carpet 14 square miles—the equivalent of 7,000 football fields—with more than a million solar panels 10 to 20 feet tall. It would be capable of producing 850 megawatts of electricity, or roughly one-tenth of Nevada's current capacity.

"It will destroy this land forever," Ms. Rebich, 33, said after riding her bicycle on the 600-foot high mesa.