(a) General. The owner or operator of an existing potline or anode bake furnace in a State that does not choose to exclude emission averaging in the approved operating permit program may demonstrate compliance by emission averaging according to the procedures in this section.

(b) Potlines. The owner or operator may average emissions from potlines and demonstrate compliance with the limits in Tables 1 through 3 of this subpart using the procedures in paragraphs (b)(1) through (3) of this section.

(1) Semiannual average emissions of TF shall not exceed the applicable emission limit in Table 1 of this subpart. The emission rate shall be calculated based on the total primary and secondary emissions from all potlines comprising the averaging group over the period divided by the quantity of aluminum produced during the period, from all potlines comprising the averaging group. To determine compliance with the applicable emission limit in Table 1 of this subpart for TF emissions, the owner or operator shall determine the average emissions (in lb/ton) from each potline from at least three runs per potline semiannually for TF secondary emissions and at least three runs per potline primary control system each year using the procedures and methods in §§63.847 and 63.849. The owner or operator shall combine the results of secondary TF average emissions with the TF results for the primary control system and divide total emissions by total aluminum production.

(2) Semiannual average emissions of POM shall not exceed the applicable emission limit in Table 2 of this subpart. The emission rate shall be calculated based on the total primary and secondary emissions from all potlines comprising the averaging group over the period divided by the quantity of aluminum produced during the period, from all potlines comprising the averaging group. To determine compliance with the applicable emission limit in Table 2 of this subpart for POM emissions, the owner or operator shall determine the average emissions (in lb/ton) from each potline from at least three runs per potline semiannually for POM secondary emissions and at least three runs per potline primary control system each year for POM primary emissions using the procedures and methods in §§63.847 and 63.849. The owner or operator shall combine the results of secondary POM average emissions with the POM results for the primary control system and divide total emissions by total aluminum production.

(3) Semiannual average emissions of PM shall not exceed the applicable emission limit in Table 3 of this subpart. The emission rate shall be calculated based on the total primary and secondary emissions from all potlines comprising the potline group over the period divided by the quantity of aluminum produced during the period, from all potlines comprising the averaging group. To determine compliance with the applicable emission limit in Table 3 of this subpart for PM emissions, the owner or operator shall determine the average emissions (in lb/ton) from each potline from at least three runs per potline semiannually for PM secondary emissions and at least three runs per potline primary control system each year for PM primary emissions using the procedures and methods in §§63.847 and 63.849. The owner or operator shall combine the results of secondary PM average emissions with the PM results for the primary control system and divide total emissions by total aluminum production.

(c) Anode bake furnaces. The owner or operator may average TF emissions from anode bake furnaces and demonstrate compliance with the limits in Table 4 of this subpart using the procedures in paragraphs (c)(1) and (2) of this section. The owner or operator also may average POM emissions from anode bake furnaces and demonstrate compliance with the limits in Table 4 of this subpart using the procedures in paragraphs (c)(1) and (2) of this section. The owner or operator also may average PM emissions from anode bake furnaces and demonstrate compliance with the limits in Table 4 of this subpart using the procedures in paragraphs (c)(1) and (2) of this section.

(1) Annual emissions of TF, POM and/or PM from a given number of anode bake furnaces making up each averaging group shall not exceed the applicable emission limit in Table 4 of this subpart in any one year; and

(2) To determine compliance with the applicable emission limit in Table 4 of this subpart for anode bake furnaces, the owner or operator shall determine TF, POM and/or PM emissions from the control device for each anode bake furnace at least once each year using the procedures and methods in §§63.847 and 63.849.

(d) Implementation plan. The owner or operator shall develop and submit an implementation plan for emission averaging to the applicable regulatory authority for review and approval according to the following procedures and requirements:

(1) Deadlines. The owner or operator must submit the implementation plan no later than 6 months before the date that the facility intends to comply with the emission averaging limits.

(2) Contents. The owner or operator shall include the following information in the implementation plan or in the application for an operating permit for all emission sources to be included in an emissions average:

(i) The identification of all emission sources (potlines or anode bake furnaces) in the average;

(ii) The assigned TF, POM and/or PM emission limit for each averaging group of potlines and/or anode bake furnaces;

(iii) The specific control technologies or pollution prevention measures to be used for each emission source in the averaging group and the date of its installation or application. If the pollution prevention measures reduce or eliminate emissions from multiple sources, the owner or operator must identify each source;

(iv) The test plan for the measurement of TF, POM and/or PM emissions in accordance with the requirements in §63.847(b);

(v) The operating parameters to be monitored for each control system or device and a description of how the operating limits will be determined;

(vi) If the owner or operator requests to monitor an alternative operating parameter pursuant to §63.848(l):

(A) A description of the parameter(s) to be monitored and an explanation of the criteria used to select the parameter(s); and

(B) A description of the methods and procedures that will be used to demonstrate that the parameter indicates proper operation of the control device; the frequency and content of monitoring, reporting, and recordkeeping requirements; and a demonstration, to the satisfaction of the applicable regulatory authority, that the proposed monitoring frequency is sufficient to represent control device operating conditions; and

(vii) A demonstration that compliance with each of the applicable emission limit(s) will be achieved under representative operating conditions.

(3) Approval criteria. Upon receipt, the regulatory authority shall review and approve or disapprove the plan or permit application according to the following criteria:

(i) Whether the content of the plan includes all of the information specified in paragraph (d)(2) of this section; and

(ii) Whether the plan or permit application presents sufficient information to determine that compliance will be achieved and maintained.

(4) Prohibitions. The applicable regulatory authority shall not approve an implementation plan or permit application containing any of the following provisions:

(i) Any averaging between emissions of differing pollutants or between differing sources. Emission averaging shall not be allowed between TF, POM and/or PM, and emission averaging shall not be allowed between potlines and anode bake furnaces;

(ii) The inclusion of any emission source other than an existing potline or existing anode bake furnace or the inclusion of any potline or anode bake furnace not subject to the same operating permit; or

(iii) The inclusion of any potline or anode bake furnace while it is shut down, in the emission calculations.

(5) Term. Following review, the applicable regulatory authority shall approve the plan or permit application, request changes, or request additional information. Once the applicable regulatory authority receives any additional information requested, the applicable regulatory authority shall approve or disapprove the plan or permit application within 120 days.

(i) The applicable regulatory authority shall approve the plan for the term of the operating permit;

(ii) To revise the plan prior to the end of the permit term, the owner or operator shall submit a request to the applicable regulatory authority; and

(iii) The owner or operator may submit a request to the applicable regulatory authority to implement emission averaging after the applicable compliance date.

(6) Operation. While operating under an approved implementation plan, the owner or operator shall monitor the operating parameters of each control system, keep records, and submit periodic reports as required for each source subject to this subpart.

[62 FR 52407, Oct. 7, 1997, as amended at 80 FR 62416, Oct. 15, 2015]