§ 49.5512 Federal Implementation Plan Provisions for Four Corners Power Plant, Navajo Nation.

(a) Applicability. The provisions of this section shall apply to each owner or operator of the coal burning equipment designated as Units 1, 2, 3, 4, and 5 at the Four Corners Power Plant (the Plant) on the Navajo Nation Indian Reservation located in the Four Corners Interstate Air Quality Control Region (see 40 CFR 81.121).

(b) Compliance Dates. Compliance with the requirements of this section is required upon the effective date of this rule unless otherwise indicated by compliance dates contained in specific provisions.

(c) Definitions. For the purposes of this section:

(1) Affirmative defense means, in the context of an enforcement proceeding, a response or defense put forward by a defendant, regarding which the defendant has the burden of proof, and the merits of which are independently and objectively evaluated in a judicial or administrative proceeding.

(2) Air pollution control equipment includes baghouses, particulate or gaseous scrubbers, and any other apparatus utilized to control emissions of regulated air contaminants which would be emitted to the atmosphere.

(3) Business Day. Business day means a normal working day, excluding weekends and Federal Holidays.

(4) Daily average means the arithmetic average of the hourly values measured in a 24-hour period.

(5) Excess emissions means the emissions of air contaminants in excess of an applicable emissions limitation or requirement.

(6) Heat input means heat derived from combustion of fuel in a Unit and does not include the heat input from preheated combustion air, recirculated flue gases, or exhaust gases from other sources. Heat input shall be in accordance with 40 CFR part 75.

(7) Malfunction means any sudden and unavoidable failure of air pollution control equipment or process equipment or of a process to operate in a normal or usual manner. Failures that are caused entirely or in part by poor maintenance, careless operation, or any other preventable upset condition or preventable equipment breakdown shall not be considered malfunctions. This rule provides an affirmative defense to actions for penalties brought for excess emissions that arise during certain malfunction episodes. An affirmative defense is not available if during the period of excess emissions, there was an exceedance of the relevant ambient air quality standard that could be attributed to the emitting source.

(8) Owner or Operator means any person who owns, leases, operates, controls, or supervises the Plant or any of the coal burning equipment designated as Units 1, 2, 3, 4, or 5 at the Plant.

(9) Oxides of nitrogen (NO_X) means the sum of nitric oxide (NO) and nitrogen dioxide (NO₂) in the flue gas, expressed as nitrogen dioxide.

(10) Plant-wide basis means total stack emissions of any particular pollutant from all coal burning equipment at the Plant.

(11) Regional Administrator means the Regional Administrator of the Environmental Protection Agency (EPA) Region 9 or his/her authorized representative.

(12) Shutdown means the cessation of operation of any air pollution control equipment, process equipment, or process for any purpose. Specifically, for Units 1, 2, or 3, shutdown begins when the unit drops below 40 MW net load with the intent to remove the unit from service. For Units 4 or 5, shutdown begins when the unit drops below 300 MW net load with the intent to remove the unit from service.

(13) Startup means the setting into operation of any air pollution control equipment, process equipment, or process for any purpose. Specifically, for Units 1, 2, or 3, startup ends when the unit reaches 40 MW net load. For Units 4 or 5, startup ends when the unit reaches 400 MW net load.

(14) 24-hour period means the period of time between 12:01 a.m. and 12 midnight.

(d) Emissions Standards and Control Measures—(1) Sulfur Dioxide. No owner or operator shall discharge or cause the discharge of sulfur dioxide (SO₂) into the atmosphere in excess of:

(i) 12.0 percent of the potential combustion concentration assuming all of the sulfur in the coal is converted to SO₂. This percent emitted is determined by a daily calculation of the plantwide heatinput weighted annual average.

(ii) 17,900 pounds of total SO₂ emissions per hour averaged over any consecutive three (3) hour period, determined on a plant-wide basis.

(2) Particulate Matter. No owner or operator shall discharge or cause the discharge of particulate matter from any coal burning equipment into the atmosphere in excess of 0.050 pounds per million British thermal unit (lb/MMBtu) of heat input (higher heating value), as averaged from three sampling runs, each at 60 minutes in duration, each collecting a minimum sample of 30 dry standard cubic feet.

(3) Dust. Each owner or operator shall operate and maintain the existing dust suppression methods for controlling dust from the coal handling and storage facilities. Within ninety (90) days after promulgation of this section, the owner or operator shall submit to the Regional Administrator a description of the dust suppression methods for controlling dust from the coal handling and storage facilities, flyash handling and storage, and road sweeping activities. Within 548 days of promulgation of this section each owner or operator shall not emit dust with an opacity greater than 20 percent from any crusher, grinding mill, screening operation, belt conveyor, or truck loading or unloading operation.

(4) Opacity. No owner or operator shall discharge or cause the discharge of emissions from the stacks of Units 4 and 5 into the atmosphere exhibiting greater than 20% opacity, excluding uncombined water droplets, averaged over any six (6) minute period, except for one six (6) minute period per hour of not more than 27% opacity.

(5) Oxides of nitrogen. No owner or operator shall discharge or cause the discharge of NO_X into the atmosphere.

(i) From either Unit 1 or 2 in excess of 0.85 lb/MMBtu of heat input per unit, and from either Units 3, 4, or 5 in excess of 0.65 lb/MMBtu of heat input per unit averaged over any successive thirty (30) boiler operating day period;

(ii) In excess of 335,000 lb per 24-hour period when coal burning equipment is operating, on a plant-wide basis; for each hour when coal burning equipment is not operating, this limitation shall be reduced. If the unit which is not operating is Unit 1, 2, or 3, the limitation shall be reduced by 1,542 lb per hour for each unit which is not operating. If the unit which is not operating is Unit 4 or 5, the limitation shall be reduced by 4,667 lb per hour for each unit which is not operating.

(e) Testing and Monitoring. Upon completion of the installation of continuous emissions monitoring systems (CEMS) software as required in this section, compliance with the emissions limits set for SO2 and NO_X shall be determined by using data from a CEMS unless otherwise specified in paragraphs (e)(2) and (e)(4) of this section. Compliance with the emissions limit set for particulate matter shall be tested annually, or at such other time as requested by the Regional Administrator, based on data from testing conducted in accordance with 40 CFR part 60, appendix A, Methods 1 through 5, or any other method receiving prior approval from the Regional Administrator. Compliance with the emissions limits set for opacity shall be determined by using data from a Continuous Opacity Monitoring System (COMS) except during saturated stack conditions (uncombined water droplets). If the baghouse is operating within its normal operating parameters, the baghouse is not fully closed, and a high opacity reading occurs, it will be presumed that the occurrence was caused by saturated stack conditions and shall not be considered a violation.