Mercury rules target area power plants

By Chuck Slothower cslothower@daily-times.com

Posted: 12/20/2011 01:00:00 AM MST

FARMINGTON — New federal mercury rules are expected to have little effect on the Four Corners Power Plant despite the plant's status as New Mexico's top mercury emitter.

That's because plant operator Arizona Public Service Co. already plans to shut down three of the plant's five units, a move that would reduce mercury emissions by 61 percent.

"Moving forward, we'll be in good shape to meet that standard," APS spokesman Damon Gross said. The looming mercury standard played a part in APS' decision to propose closing the three older units, he said.

The EPA was expected to release the mercury rules Monday, but had not done so by press time.

The planned closure is part of APS' proposal, announced in November 2010, to buy shares of the plant's two newest units from Southern California Edison.

APS has agreed to pay $294 million for the California utility's 48 percent share of units 4 and 5, which would give the Phoenix-based utility majority ownership of units 4 and 5. APS currently owns only 15 percent of those units.

The purchase still is awaiting approval from state and federal regulators.

"We have been preparing to comply with a new mercury standard for several years," said Alan Bunnell, another APS spokesman.

Shutting down the plant's three older units would cut electricity generation by 560 megawatts, but also would sharply reduce emissions of several pollutants. In addition to reducing mercury emissions, nitrogen oxide emissions would fall by 36 percent, particulates by 43 percent, carbon dioxide by 30 percent and sulfur dioxide by 24 percent, APS says.

"For mercury, the units already have bag houses, and we will be using activated carbon injection," Bunnell said.

Four Corners Power Plant, which went online in 1963, is part of a generation of large, aging, coal-fired power plants targeted by the EPA's mercury rules.

The plant emitted 465 pounds of airborne mercury in 2010, by far the most in New Mexico. San Juan Generating Station, the other coal-fired power plant in Northwest New Mexico, emitted only 10 pounds, according to the EPA.

Four Corners is the larger of the two plants, producing 2,040 megawatts of electricity to about 300,000 households in New Mexico, Arizona, California and Texas.

San Juan Generating Station likely will be able to meet the new mercury standard without any further upgrades, said Don Brown, spokesman for operator Public Service Co. of New Mexico. An upgrade completed in 2009 gave the plant the ability to remove 99 percent of its mercury emissions.

"We believe the plant's in very good shape to meet that rule," Brown said.

While there are worries nationally that the mercury rules will lead to layoffs, none are planned at Four Corners, Gross said. Any needed job cuts will be achieved through routine employee retirements and attrition.

"Assuming our plan is approved as proposed, there will be no layoffs," Gross said.

Units 4 and 5 may have the advantage of being easier to retrofit, said Mike Eisenfeld, New Mexico energy coordinator for San Juan Citizens Alliance, a Durango, Colo.-based environmental group.

But Eisenfeld questioned the wisdom of continuing to invest in a decades-old coal-fired plant.

"It's going to be tough for them to continue to rely on these facilities," he said. "They're getting into the retrofit mode with everything. The price of coal is going up, up, up, and the price of renewable is coming down."

Eisenfeld added, "Continuing to rely on a 50-year-old coal plant is not very visionary, in my opinion."