Region 9, Air Permits OfficeOverview of EPA ProposedRulemaking forNavajo Generating StationPlan to Reduce Emissions of Oxides ofNitrogen to Improve Visibility at FederallyProtected National Parks Affected by NGS1Region 9, Air Permits Office2Region 9, Air Permits OfficeOverview• On February 5, EPA published our proposedBART determination and an alternative to BARTfor NGS• We proposed two things:– an emission limit for oxides of nitrogen (NOx)achievable with installation of selective catalyticreduction (SCR) in 5 years (BART) and– a framework to give NGS credit for early NOxreductions and provide NGS with more flexibility onthe timing of compliance (alternative to BART)3Region 9, Air Permits OfficeHistory of NGS• NGS is located on Navajo Nation and burns coal thatis mined on reservation lands of the Navajo Nationand Hopi Tribe• U.S. Bureau of Reclamation owns 24.3% of NGS forthe benefit of the Central Arizona Project• NGS plays important roles in Arizona:– Employment– Source of revenue to Navajo Nation and Hopi Tribe– Source of electricity– Electricity is also used to pump CAP water and fulfillterms of several water settlement agreements withtribes located in Arizona4Region 9, Air Permits OfficeWhy Are We Evaluating NGS?5• Congress required EPA to improve visibility atNational Parks and Wilderness Areas (Class I areas)– Regional Haze Program• Large, old sources of air pollution that affect visibilityin Class I areas must be evaluated to determine ifnew air pollution controls should be required (BestAvailable Retrofit Technology – BART)• NGS affects visibility at 11 Class I areas, includingGrand Canyon and Canyonlands and is subject to theBART requirement of the Regional Haze ProgramRegion 9, Air Permits Office• Air pollutants (for example, gases like NOxthatform particulate matter) cause regional haze• By reducing emissions of air pollutants that causehaze, we can improve visibility• The same pollutants that impair visibility are aconcern for human health, therefore reducinghaze also improves air quality• EPA or State Agencies evaluate whether newcontrols should be required for all facilities thatare subject to BART requirementHow do we improve visibility?6Region 9, Air Permits Office• BART is determined based on a 5-factor analysis– Factor 1 – How much would controls cost the facility?– Factor 2 – Are there energy, economic, or otherenvironmental impacts of the control?– Factor 3 – What are the existing controls at the facility?– Factor 4 – What is the remaining useful life of thefacility?– Factor 5 – How will visibility improve by addingcontrols?How is BART determined?7Region 9, Air Permits OfficeBrief Overview of 5-Factor Analysis8Region 9, Air Permits Office• Based on our 5-factor analysis, EPA determinedthat installation of SCR + LNB/SOFA at NGS toreduce NOxemissions:– is cost-effective– would not create a competitive disadvantage for NGS– would result in a perceptible improvement in visibility atthe Class I areas affected by NGSWhy Did We Propose New Controls?9Region 9, Air Permits Office• Given the importance of NGS to tribes located in Arizonaand its location on tribal land, it is appropriate to provideadditional flexibility to the owners• Compliance timeframes for alternatives to BART under theRegional Haze Rule that apply on state land do not applyon tribal land• Under the Tribal Authority Rule, EPA has discretion todetermine if and when a FIP is necessary and appropriate,including the timeline for complying with thoserequirementsWhy is EPA Proposing an Alternative?10Region 9, Air Permits Office• The Regional Haze Rule (RHR) requires either BART oranalternative measure that will achieve greater reasonableprogress than BART (more emission reductions)• EPA is proposing to give NGS credit for early and voluntary NOxreductions in order to extend the compliance date to 2023 formeeting BART limits• This alternative achievesgreater reasonable progress thanBART• EPA included a framework for stakeholders to consider datesbeyond 2023 by implementing additional emission reductionsthat would ensure greater reasonable progress than BARTFramework for Considering Alternatives11Region 9, Air Permits Office12• EPA will hold public hearings at least 30 days prior to the closeof the comment period• In your comments, please provide supplemental informationand documentation to support your comment• EPA has received several requests to extend the publiccomment period by an additional 90 days, which we will grant• EPA anticipates stakeholders willsuggest other alternatives toBART that ensure additional emission reductions in exchangefor more time to comply with the BART limits• EPA may put forth a supplemental proposal if suggestedalternatives achieve greater reasonable progress than BARTWhat Happens Next?Region 9, Air Permits Office13• EPA will review and consider all comments beforemaking a final decision• We will respond to all comments in writing andincorporate any changes to the proposal as a resultof comments in our final decision• Documents will also be posted online and in ourdocket for this rulemakingWhat Happens After the Comment Period?Region 9, Air Permits Office14For Further InformationNameRolePhoneEmailColleenMcKaughanAssociate Director,Air Division520.498.0118McKaughan.Colleen@epa.govAnn LyonsOffice of RegionalCounsel415.972.3883Lyons.Ann@epa.govAnita LeeStaff Lead, AirDivision415.972.3958Lee.Anita@epa.gov