The plants were expected to supply 550 megawatts of renewable energy, enough to power about 170,000 homes, Secretary of Interior Secretary Sally Jewell said in a release Wednesday. More than 700 jobs will be created through construction and operations, she said.
The Stateline Solar Farm Project is slated for a site in the Mojave Desert in San Bernardino County, Calif., near the Nevada line.
Across the border, the Silver State South Solar Project will be located near Primm, Nev. It will be adjacent to the smaller Silver State North facility, which is already providing power.
Both new public lands projects were proposed by the company First Solar and have commitments from Southern California Edison to purchase the plants' output for 20 years, the secretary said.
Throughout the review process, environmentalists voiced concerns that construction will negatively impact populations of desert tortoises in the Ivanpah Valley.
The plants would effectively isolate the tortoises' habitats, eventually shrinking the gene pool, said Dr. Michael J. Connor, California Director of the Western Watersheds Project. The desert tortoise was listed as threatened in 1994.
"Once you have populations that are isolated they are more prone to chance events like disease die-offs and the like," he said.
In November the group Defenders of Wildlife filed a notice of intent to sue the government under the Endangered Species Act to block the projects, California Program Director Kim Delfino said.
"We strongly support renewable energy projects and have supported solar plants," she said, pointing out the organization backed the Silver State North project. "These two we do not support."
The government said Wednesday it would work to protect the tortoises by expanding the Ivanpah Desert Wildlife Management Area by more than 20,000 acres.