March 31, 2011
San Juan Generating Station Set to Outperform Proposed Federal Mercury Limits
Albuquerque:Thanks to a $320 million environmental upgrade completed two years ago, PNM's San Juan Generating Station is set to outperform recently proposed federal limits on mercury emissions, according to plant data and an initial review of the draft federal rule by PNM environmental experts.
Based on the mercury content of San Juan's coal, and ongoing data collection by the plant's state-of-the-art emissions monitors, each of the plant's four units is removing more than the EPA-proposed removal rate of 91 percent.
"A decision we made in 2005 to include mercury reductions as part of a larger environmental upgrade continues to pay dividends," said Maureen Gannon, director, Environmental Services. "Not only have we significantly reduced emissions since the upgrade, but the plant appears to be removing more mercury than what the U.S. Environmental Protection Agency would require."
The plant's overall emissions of mercury have been reduced dramatically since the environmental upgrade, decreasing from 496 pounds in 2006 to 66 pounds in 2010. As part of that upgrade, San Juan installed activated carbon injection to maximize mercury removal from the plant's emissions – a technology the EPA web site characterizes as "the most highly advanced technology" for mercury removal.
Gannon said the company is still analyzing provisions of the draft rule related to certain other emissions, including arsenic, chromium, nickel and acid gases, to determine whether its current operations meet proposed limits on those emissions.
Final Days of Public Comment Period on Separate EPA Proposal for San Juan
Meanwhile, the opportunity for public comment on a separate EPA proposal for San Juan, which could significantly affect the electric rates of customers served by the plant, is set to end April 4. As part of its effort to address regional haze, EPA has proposed requiring San Juan to install selective catalytic reduction on all four of the plant's units – a requirement that PNM estimates would cost at least $750 million and achieve no meaningful haze reduction compared to technology already installed.
The N.M. Environment Department has offered its own plan to comply with federal haze requirements, proposing that San Juan install selective non-catalytic reduction. That technology is significantly less expensive than what EPA has proposed. Gannon said that while PNM is still studying the state proposal, it is encouraged to see the potential economic impact on customers being considered as part of the regulatory process.
Public comments on the EPA proposal can be submitted online via a link from Regulations.gov.
The N.M. Environmental Improvement Board has scheduled public hearings on the state's proposal for June 1-3.