SAN FRANCISCO — Federal officials approved a plan on Friday that sets aside 445 square miles of public land for the development of large-scale solar power plants, cementing a new government approach to renewable energy development in the West after years of delays and false starts.
At a news conference in Las Vegas, Interior Secretary Ken Salazar called the new plan a ‘‘roadmap . . . that will lead to faster, smarter utility-scale solar development on public lands.’’
The plan replaces the department’s previous first-come, first-served system of approving solar projects, which let developers choose where they wanted to build utility-scale solar sites and allowed for land speculation.
The department no longer will decide projects within the zones on a case-by-case basis as it had since 2005, when solar developers began filing applications.
Instead, the department will direct development to land it has identified as having fewer wildlife and natural-resource obstacles.
The government is establishing 17 new ‘‘solar energy zones’’ on 285,000 acres in six states: California, Nevada, Arizona, Utah, Colorado, and New Mexico. More than half of the land — 153,627 acres — is in Southern California.
The department also established 19 million acres — nearly 30,000 square miles — of “variance zones’’ that will allow developers to propose solar projects in those areas. Environmental and other review of projects proposed in variance zones would be handled on a case-by-case basis.
The Obama administration has authorized 10,000 megawatts of solar, wind, and geothermal projects that, when built, would provide enough energy to power more than 3.5 million homes, Salazar said.
Secretary of Energy Steven Chu said the effort will help the United States stay competitive.
‘‘There is a global race to develop renewable energy technologies — and this effort will help us win this race by expanding solar energy production while reducing permitting costs,’’ Chu said in a statement.
The new solar energy zones were chosen because they are near existing power lines, allowing for quick delivery to energy-hungry cities. Also, the chosen sites have fewer of the environmental concerns — such as endangered desert tortoise habitat — that have plagued other projects.
Environmental groups like the Nature Conservancy that had been critical of the federal government’s previous approach to solar development in the desert applauded the new plan.
‘‘We can develop the clean, renewable energy that is essential to our future while protecting our iconic desert landscapes by directing development to areas that are more degraded,’’ said Michael Powelson, the conservancy’s North American director of energy programs.
Some solar developers that already are building projects were complimentary of the new approach, saying it will help diversify the country’s energy portfolio more quickly.
Still, some cautioned that the new plan could still get mired in the same pattern of delay and inefficiency that hampered previous efforts, and they urged the government to continue pushing solar projects forward.
‘‘The Bureau of Land Management must ensure pending projects do not get bogged down in more bureaucratic processes,’’ said Rhone Resch, president of the Solar Energy Industries Association.
Salazar said the country was importing 60 percent of its oil four years ago, and that number has to 45 percent today.
‘‘We can see the energy independence of the United States within our grasp,’’ he said.