Earth Notes: A Sunny Future for Desert Power—But What About the Tortoises?

Dec 12, 2012

Sunshine is endemic to the desert Southwest. So is a venerable reptile, the Agassiz’s desert tortoise.

Agassiz Desert Tortoise
Credit Gerald and Buff Corsi © California Academy of Sciences

Now human energy needs are bringing the two into conflict, as some of the animals live in the path of a huge solar “farm” being built in the California desert.

When finished, the 2.2-billion-dollar Ivanpah Solar Electric Generating System will be the world’s largest concentrating solar thermal plant. With 170,000 mirror heliostats and three tall “power towers” spread over 3,500 acres of public land, it will provide electricity to more than 140,000 homes.

The tortoise, a threatened species, is adapted to the continent’s hottest, driest desert. They may occasionally seek the shade and greenery beneath solar panels, according to biologists in northern Arizona. But they prefer less disturbed desert tracts, where they browse on desert greenery and construct deep burrows to protect themselves from temperature extremes.

The project developer, BrightSource Energy, has erected fifty miles of fence to keep tortoises out, reduced the project’s footprint, and given up 10 percent of its potential power output. The company has also funded efforts to relocate tortoises and raise young hatchlings in a nursery, which may help tortoise populations elsewhere.

The Ivanpah project is now almost 70 percent complete. The bigger question may be what will happen with dozens of other renewable projects planned across many more acres of the sunny Southwest. Can large-scale clean industry coexist with native animals and plants? Many eyes are on the desert tortoise, seeing if it will provide an answer to that question.

Earth Notes is produced by KNAU and the Master of Arts in Sustainable Communities Program at Northern Arizona University.