NR 428.04(2)(i)2. 2. The emissions unit burns the secondary fuel only during any of the following periods:

NR 428.04(2)(i)2.a. a. Supply interruption or curtailment of primary fuel. The secondary fuel usage under this paragraph may not exceed 500 hours within a 12 consecutive month time period unless the owner or operator obtains a fuel variance under s. NR 436.06.

NR 428.04(2)(i)2.b. b. Periodic testing, maintenance, or operator training of the secondary fuel when the periodic testing, maintenance, or operator training does not exceed a combined total of 48 hours during any calendar year.

NR 428.04(2)(i)3. 3. The secondary fuel constitutes less than 1 percent on an energy equivalent basis of the emissions unit’s fuel consumption within the most recent 12 consecutive month time period.

NR 428.04(3) (3) Monitoring requirements.

NR 428.04(3)(a) (a) General requirements.

NR 428.04(3)(a)1. 1. The owner or operator of each NOx emissions unit subject to the requirements of sub. (2) shall comply with the monitoring requirements of subch. III.

NR 428.04(3)(a)2. 2. The emissions measurements recorded and reported in accordance with subch. III shall be used to determine compliance by the unit with the applicable NOx emissions performance standard under sub. (2).

NR 428.04(3)(b) (b) Specific requirements. The owner or operator of each NOx emissions unit subject to the requirements of sub. (2) shall determine the unit’s average NOx emission rate using methods and procedures specified in 40 CFR part 60, Appendix B, incorporated by reference in s. NR 484.04 (21), or other emissions monitoring methods approved by the department.

NR 428.04(4) (4) Recordkeeping and reporting requirements.

NR 428.04(4)(a) (a) Except as provided in subd. 1., the owner or operator of each NOx emissions unit subject to the requirements of this section shall keep on site at the source each of the following documents for a period of 5 years from the date the document is created.

NR 428.04(4)(a)1. 1. All emissions monitoring information, in accordance with subch. III; except that, to the extent that subch. III provides for a 3-year period for record retention, the 3-year period shall apply.

NR 428.04(4)(a)2. 2. Copies of all reports, compliance certifications and other submissions and all records made or required under the NOx emissions performance program.

NR 428.04(4)(b) (b) The owner or operator of the NOx emissions source shall submit the compliance reports and certifications required under the NOx emissions performance program in conjunction with those required under the construction permit requirements of ch. NR 406 and the operation permit requirements of s. NR 407.09.

NR 428.04(4)(c) (c) The owner or operator claiming exemption from the requirements under sub. (2) pursuant to sub. (2) (i) shall keep a record of all of the following:

NR 428.04(4)(c)1. 1. Each occurrence when a secondary fuel was burned in accordance with the provisions under sub. (2) (i).

NR 428.04(4)(c)2. 2. The reason for each occurrence when a secondary fuel was burned in accordance with the provisions under sub. (2) (i).

NR 428.04(4)(c)3. 3. The monthly and yearly total hours for each occurrence when a secondary fuel was burned in accordance with the provisions under sub. (2) (i).

NR 428.04(4)(c)4. 4. Other relevant information as required by the department.

NR 428.04 History History: Cr. Register, January, 2001, No. 541, eff. 2-1-01; CR 02-076: cr. (2) (g) 3. Register November 2002 No. 563, eff. 12-1-02; CR 03-049: am. (2) (g) 1., cr. (2) (g) 4. Register December 2003 No. 576, eff. 1-1-04; CR 07-016: am. (2) (h) 1. and 2. Register July 2007 No. 619, eff. 8-1-07; CR 08-103: am. (1) and (3) (b) Register August 2009 No. 644, eff. 9-1-09; CR 23-017: am. (2) (g) 1. d., cr. (2) (i), (4) (c) Register March 2024 No. 819, eff. 4-1-24.

NR 428.05 NR 428.05 Requirements and performance standards for existing sources.

NR 428.05(1) (1) Applicability. The requirements of this section apply to emissions units described in this section that are located in the county of Kenosha, Manitowoc, Milwaukee, Ozaukee, Racine, Sheboygan, Washington or Waukesha and that were initially constructed on or before February 1, 2001.

NR 428.05(2) (2) NOx emissions optimization.

NR 428.05(2)(a) (a) The requirements of this subsection do not apply to emissions units which are subject to the emission limits of sub. (3).

NR 428.05(2)(b) (b) Except as provided under par. (a), (c), or (f) the following categories of NOx emissions units listed under this subsection shall complete a combustion optimization to minimize NOx emissions in accordance with s. NR 439.096 by December 31, 2002:

NR 428.05(2)(b)1. 1. Solid fuel-fired boilers with a maximum design heat input of 75 million Btu per hour or greater and operated during the 2000 ozone season or a later ozone season with a capacity factor of at least 20%.

NR 428.05(2)(b)2. 2. Natural gas-fired boilers with a maximum design heat input of 75 million Btu per hour or greater and operated during the 2000 ozone season or a later ozone season with a capacity factor of at least 20%.

NR 428.05(2)(b)3. 3. Distillate or residual fuel oil-fired boilers with a maximum design heat input of 75 million Btu per hour or greater and operated during the 2000 ozone season or a later ozone season with a capacity factor of at least 20%.

NR 428.05(2)(b)4. 4. Cement kilns, lime kilns and calciners with a maximum design heat input of 75 million Btu per hour or greater and operated during the 2000 ozone season or a later ozone season with a capacity factor of at least 20%.