EPA extends comment period for Navajo NOx control plan

The U.S. Environmental Protection Agency has extended the comment deadline and plans five local hearings on a regional haze NOx finding that impacts the coal-fired Navajo Generating Station (NGS).

On Feb. 5, EPA proposed a Best Available Retrofit Technology (BART) determination for NOX for Navajo, located on the Navajo Nation, and provided a three-month period for public comments, to close on May 6. The Navajo Nation, Gila River Indian Community, and other affected stakeholders requested a 90-day extension of the comment period to allow time for stakeholders to develop an alternative to EPA’s proposed BART determination that achieves greater reasonable progress. On March 19, EPA extended the close of the public comment period to Aug. 5. On June 10, EPA signed a notice of its intent to hold five public hearings in the state of Arizona.

On June 20, the Salt River Project (SRP), the operator and a co-owner of NGS, submitted a letter on behalf of six stakeholders, including the Navajo Nation and Gila River Indian Community, describing the development of a stakeholder alternative, and requesting another extension of the comment period so final details of that plan could be worked out. So, in a notice to be published in the July 9 Federal Register, EPA said it is extending the comment period by 60 days to Oct. 4.

EPA also intends to hold the five public hearings at locations on the Navajo Nation and the Hopi Tribe, as well as in Page, Phoenix, and Tucson, Ariz.

On Feb. 5, EPA had proposed a BART determination to require NGS to achieve a nearly 80% reduction of its current overall NOX emission rate. EPA also proposed an alternative to BART that would provide flexibility to NGS in the schedule for the installation of new post-combustion controls. EPA’s proposed alternative to BART credits NGS for its early and voluntary installation of new combustion controls to reduce NOX emissions beginning in 2009.

The three 750-MW units at NGS were constructed in the 1974-1976 period. It gets coal from the Kayenta mine in Arizona of Peabody Energy (NYSE: BTU), which is a mine that would shut without this business. NGS is co-owned by six entities including the Salt River Project (SRP), which also acts as the facility operator.

EPA is proposing to determine a plantwide emission limit of 0.055 lb/MMBtu as BART for NGS, based on a rolling average of 30 boiler operating days, achievable with the installation of selective catalytic reduction (SCR), the most costly NOx control technology. Under the Clean Air Act, compliance with emission limits determined as BART must be “as expeditious as practicable but in no event later than five years” after the effective date of the final BART determination. That date would be 2018, if the rule is finalized in 2013, or 2019 if, due to a need for extended public discussion or a supplemental proposal, the rule is finalized in 2014.

In the Feb. 5 proposal, EPA put out a BART alternative (Alternative 1) for NGS that would require the plant to meet a NOx limit of 0.055 lb/MMBtu on one unit per year in 2021, 2022, and 2023.

About Barry Cassell 20414 Articles
Barry Cassell is Chief Analyst for GenerationHub covering coal and emission controls issues, projects and policy. He has covered the coal and power generation industry for more than 24 years, beginning in November 2011 at GenerationHub and prior to that as editor of SNL Energy’s Coal Report. He was formerly with Coal Outlook for 15 years as the publication’s editor and contributing writer, and prior to that he was editor of Coal & Synfuels Technology and associate editor of The Energy Report. He has a bachelor’s degree from Central Michigan University.