LAS VEGAS — Federal officials have approved a solar plant on an Indian reservation outside Las Vegas, marking the nation’s first commercial-grade solar energy project on tribal land and new territory for the Obama administration’s renewable energy agenda.

U.S. Interior Secretary Ken Salazar said today he signed off on a plan with the Moapa Band of Paiute Indians that will launch a 350-megawatt solar plant capable of powering 100,000 homes.

“We do not want Indian country to be left behind as we move forward with the new energy front in the United States,” Salazar said in a conference call with reporters.

The project, proposed by K Road Moapa Solar LLC, is planned on 2,000 acres of the tribe’s reservation. It will connect to and help power the Moapa Travel Plaza, a truck stop near the entrance of Valley of Fire State Park, which provides much of the small tribe’s income.

Officials plan to break ground this fall, and estimate the project will create 400 jobs at the peak of construction. They estimate between 15 and 20 of those jobs would be permanent.

The tribal initiative is part of a broader Interior Department effort to bring solar, wind and geothermal projects to public lands. It also marks the 31st utility-scale project approved on public lands since Obama took office in 2009.

Officials said the Interior Department is also working to revamp federal surface leasing regulations in an effort to streamline energy project development on tribal lands.

“Indian country has a wealth of resources,” said Donald “Del” Laverdure, the acting assistant secretary of Indian affairs. He said the initiative ensures “tribal governments can also participate in the American dream.”