LAUGHLIN, Nev. — A large coal-fired power plant at the center of a dispute a few years ago will close at the end of the year rather than violate a court-ordered deadline to install an estimated $1.1 billion in pollution-control measures.

Southern California Edison said Thursday the Mohave Generating Station near Laughlin would close. The plant has provided the utility with 7 percent of its electricity, but the company said its 13 million customers would not be immediately affected because of other power sources.

Under a 1999 consent decree won by environmental groups, the aging Mohave plant was required to upgrade its pollution controls or close by Jan. 1, 2006.

The groups had argued the 1,580-megawatt plant, about 100 miles south of Las Vegas, had repeatedly violated the Clean Air Act, emitting high amounts of sulfur dioxide, nitrogen oxide and fine particles and contributing to haze at the Grand Canyon.

The utility, majority owner and operator of the coal plant, had hoped to keep it open as natural gas prices have continued to rise.

In a filing Thursday with the California Public Utilities Commission, Edison said it planned to continue negotiations aimed at keeping the plant open but expected to close it for at least a few months. The plant is the only customer of the Black Mesa mine near Kayenta, Ariz., which provides about 160 jobs to members of the Navajo Nation. The mine, run by Peabody Energy Corp., will likely be forced to close.

"It was the environmental groups that helped bring this about — for altruistic reasons of course — but the result is that a lot of breadwinners are going to be out of work," said George Hardeen, a spokesman for the Navajo Nation.

"We will lose about 160 jobs, and these are some of the best jobs on the Navajo Nation, paying upwards of $70,000. It will undoubtedly impact an already weak Navajo Nation economy."

Environmentalists said they sympathized with the tribes, but argued Edison had plenty of time to fix the plant's pollution problems. They suggested Edison invest in renewable energy sources on tribal land.

"It's a smart investment for California ratepayers to take income from a dirty power plant and reinvest it in clean energy, in a way that benefits the people who have been exploited all of these years by the greater metropolitan centers of the West," said Roger Clark, director of the Grand Canyon Trust's air and energy program.