LAS VEGAS -- Southern Nevada's main electric utility will pay $60.7 million to upgrade a Las Vegas-area power plant and settle a federal Clean Air Act complaint, officials said Wednesday.

The agreement announced by Nevada Power Co. and two federal agencies represented the second recent announcement that the Las Vegas-based utility will pay tens of millions of dollars to resolve air pollution violations.

Ten weeks ago, officials announced the company, a division of Reno-based Sierra Pacific Resources Inc., would pay $90 million to settle an air pollution case involving the Nevada Division of Environmental Protection and the federal Environmental Protection Agency.

The EPA said the new settlement, which also involved the federal Justice Department, was the first with an electric utility over alleged violations of New Source Review provisions of the Clean Air Act at a gas-fired power plant.

Nevada Power admitted no wrongdoing. But it agreed to pay a $300,000 fine and install about $60 million worth of pollution controls by next year at the gas-fired Clark Generating Station near Henderson, about 10 miles southeast of the Las Vegas Strip.

The upgrades are expected to cut emissions of nitrogen oxide air pollutants by about 86 percent, or some 2,300 tons a year, the EPA said.

"The substantial reductions in air pollutants from Clark station will improve the air quality in Nevada,'' Ronald J. Tenpas, acting assistant attorney general for the Justice Department's environmental and natural resources division, said in a statement.

The company also pledged to contribute $400,000 to fund a solar panel array at a planned Vegas PBS Educational Technology Campus.

Roberto Denis, senior vice president of energy supply for Sierra Pacific Resources, said in a statement that Nevada Power was in compliance with applicable laws, regulations and permits and was committed to meeting environmental standards.

Nevada Power spokesman Kevin Rademacher said the $700,000 for the fine and the investment in the solar panel array would be paid by company shareholders, not ratepayers.

The state Public Utilities Commission in April approved the $60 million in upgrades as part of a 2006 company resource plan.

Nevada state Consumer Advocate Eric Witkowski said he could not immediately say what effect the cost of the settlements could have on Nevada Power rates. Las Vegas-area residential customers saw rates increase about 11.6 percent on June 1 -- or about $23 a month for the typical home.

"We may not oppose the investment, but we may oppose any fines and penalties paid to the EPA,'' Witkowski said. "You want them to comply. But whether they are all reasonable costs, we'll have to take a look and see.''

The EPA said the settlement filed Wednesday in U.S. District Court in Nevada was subject to a 30-day public comment period.

It settled allegations that Nevada Power failed to obtain a permit and install emission controls when it upgraded turbine blades at the Clark power plant in 1992.

The company said Clark County officials determined that no permit was needed, but the EPA later overruled that decision.

"While Nevada Power still believes it complied fully with the law, it has chosen to reduce emissions and improve air quality, rather than litigate this dispute with EPA,'' it said in the statement.

The company also acknowledged no violations or liability in the April 3 announcement of the $90 million settlement. Officials called that deal, stemming from emissions violations in 2005, the largest enforcement action in state Division of Environmental Protection history.

It requires nearly $85 million in technology upgrades at the coal-fired Reid Gardner plant, about 40 miles northeast of Las Vegas, plus a $1 million fine, and $4 million in energy conservation projects.

Nevada Power provides electricity to about 800,000 residential and business customers in a 4,500 square mile area of southern Nevada.