LAS VEGAS - One of California's three major electricity providers will ask the Nevada State Environmental Commission on Monday for a temporary variance that would allow its Laughlin power plant to produce smoke with more pollutants than allowed by Nevada law.
The variance being sought by Southern California Edison only would permit an easing of standards regarding the visual density of the smoke plumes produced by its Mohave Generating Station, one of the nation's biggest air polluters.
''Granting this variance would not affect public health or environmental safety,'' said Allen Biaggi, administrator of the Nevada Environmental Protection Division. ''It only affects pollutants that can be seen. It only has a possible aesthetic impact.''
SoCal Edison - a privately owned utility that has been hemorrhaging money because of California's soaring electricity prices - is seeking the variance in case the administrator of the state's power grid declares an energy emergency, a move that can only be taken should power-supply levels dip low enough to cause rolling blackouts.
The Mohave Generating Station, about 100 miles southeast of Las Vegas, then would be ordered to increase power production in its two 790-megawatt boilers, which usually run 50 to 60 megawatts below capacity.
That in turn could cause Mohave's smokestacks to produce plumes with more than 30 percent opacity, the limit under Nevada law.
Smoke with 100 percent opacity completely obscures the air. Zero percent opacity refers to completely transparent air.
Nader Mansour, manager of environmental regulation for SoCal Edison in Rosemead, Calif., said a 1 percent to 5 percent increase in the plant's opacity level would not be noticeable to someone looking at the plumes.
''The commission has to measure the public health issue of not having power throughout the West with the opacity criteria,'' Biaggi said. ''They must find a balance between those two ideas: ensuring public safety and aesthetics.''
The commission granted the company its first variance earlier this year, between June 22 and Oct. 20. During those four months, the Laughlin plant exceeded 30 percent opacity by 1 percent during a single six-minute period.
The Environmental Protection Agency estimates that the Mohave Generating Station releases more than 40,000 tons of sulfur dioxide per year and is one of the largest sources of the pollutant in the West.
The EPA has found that when wind blows strongly enough in the direction of the Grand Canyon, about 100 miles northeast of the plant, the pollutants contribute to haze in the canyon.