June 27, 2001

Two large power plants that will supply Californians with electricity will greatly boost emissions in Mexicali and Imperial County, a cross-border region already plagued by air quality problems.

The plants are being built outside Mexicali, Mexico, just 10 miles from the California city of Calexico.

When the plants begin operating in 2003, they will send more than 4,000 tons of pollutants a year into the skies above Mexicali and neighboring Imperial County, says a recent report by the Imperial County Air Pollution Control District.

"We're not opposed to power plants, but we are concerned about the emission levels and the impact it will have on the health of the citizens of the two areas and the impact it could have on the region's economic development," said Steve Birdsall, a district pollution control officer.

"We believe that could be significant," he said.

One plant is being built by Sempra Energy of San Diego and, the report notes, will be outfitted with the latest pollution control devices.

The other, being built by the global power generation firm InterGen, wouldn't meet California power plant requirements but is well within Mexican standards.

At projected levels, emissions from the two plants will boost total emissions in Mexicali by 12.6 percent. Emissions in the entire cross-border air basis will rise 7.7 percent.

The report was based on data from permit applications filed with the Mexican government.

Today, Imperial County's Board of Supervisors is scheduled to discuss the air quality problem for a second time with representatives of InterGen. Meanwhile, a coalition of concerned citizens, business leaders and community activists from both sides of the border has formed the Imperial Valley Clean Air Stakeholders Group and launched a campaign to address concerns about the plants.

Representatives of that group are sending letters to government officials in Baja California and California to complain that the emissions are too high. They plan to make the same point soon in meetings with representatives of the two companies.

Joel Epstein, an InterGen consultant, said the company's research indicates the emissions won't have a significant impact on either side of the border. Nevertheless, he said, InterGen will present the supervisors a voluntary initiative today that should address local concerns.

Epstein wouldn't reveal details of the initiative but said it "will both improve the emissions profile as well as improve the overall quality of the Imperial Valley region on both sides of the border."

The Imperial County report underscores the fact that environmental standards for power plants are much less stringent in Mexico:

 If built in the United States, the plants would be required to be fitted with equipment known as Best Available Control Technology and continuous emission monitors. Neither technology is mandatory in Mexico.

 Mexico doesn't impose any limits on carbon monoxide emissions, which are tightly regulated under the U.S. Clean Air Act. Carbon monoxide takes oxygen out of the bloodstream, making it a concern for people with heart disease.

 Mexico's standards for nitrogen oxides, which contribute to smog and damage the lungs, are significantly lower than U.S. limits.

 Mexico doesn't require data on particulate emissions, which can damage the lungs and contribute to asthma, emphysema, respiratory infection, heart attack and smaller lung growth in children.

Because of the two plants' total emission levels, the report says they will have "a far greater negative impact on U.S. and Mexican citizens living in the border region than if these plants were constructed a few miles to the north in the United States."

Both plants have building and environmental permits from the Mexican government and are ready to start construction about a mile apart in Colonia Progreso on Mexicali's western edge.

Together, the plants could provide enough electricity to power about 600,000 homes in California.

The 500-megawatt Sempra Energy plant, Termoeléctrica de Mexicali, will export all its electricity to U.S. consumers.

The InterGen plant, called La Rosita, will export about 30 percent of its output. The rest will serve customers in Baja California.

La Rosita was originally planned to generate 750 megawatts, but another 250 megawatts capacity reportedly was added after the Imperial County air quality study was done.

The study also didn't include data for two other power plants that could be built in the Mexicali area. One is a 257-megawatt natural-gas-fired plant; the other is a coal-fired plant with an unknown capacity.

Mexico is urging other energy companies to build plants in Baja California to export electricity to energy-strapped California. In La Jolla several weeks ago, Mexican Energy Secretary Ernesto Martens said the country won't set any limits on the number of plants it will allow.

The Sempra and InterGen plants will be fired by natural gas, a cleaner, more efficient fuel than fuel oil or coal. Nevertheless, natural gas does produce emissions.

Sempra Energy is fitting its plant with Best Available Control Technology and continuous emission monitors to cut the output.

InterGen is using neither of the technologies, which are required on all new plants in the United States. The only pollution control technology the company plans to install is low-nitrogen oxide burners. Its backup power source is a dual-fuel diesel engine, which usually runs dirtier than natural gas and produces more particulates.

As a result, air emissions of nitrogen oxides and carbon monoxide at InterGen's La Rosita plant will total 21,026 pounds a day, or 3,838 tons a year.

Sempra has pledged that emissions at its plant will be less than one-tenth as much -- 2,066 pounds a day, or 377 tons a year.

The plant, "as clean and efficient as any plant that can be constructed," according to Sempra spokesman Art Larson, is the only facility in Mexico fitted with the pollution controls. As such, he said, it will be the cleanest power plant in the country.

Pollution levels in Imperial County and Mexicali already are too high, said Jan Cortez, an official of the American Lung Association of San Diego and Imperial Counties. The association is one of the organizers of the Clean Air Stakeholders Group.

The cross-border region, with a population of 900,000, shares an air basin polluted by industrial manufacturing, dust and pesticide residue from agricultural activities, diesel bus and truck exhaust, cars without pollution controls and idling traffic at the border crossings.

Even without the new plants, Calexico's carbon monoxide levels exceed those established by the U.S. Clean Air Act. And Mexicali's carbon monoxide levels exceeded Mexico's standard on 77 days in 1998, the latest year for which data is available.

The Clean Air Stakeholders Group believes measures could be taken to offset the pollution to be generated by the new plants, Cortez said. Trucks and buses running on diesel fuel could be converted to natural gas, she said. Or they could be retrofitted with particulate-matter traps.

Such measures are being used in the San Diego region so a power plant can be built on Otay Mesa without exceeding U.S. air pollution limits.

"Offsets haven't even been discussed with InterGen and Sempra about the plants they're building," Cortez said.