Ind. Admin. Code tit. 326, r. 6.8-2-26 – NIPSCo-Dean H. Mitchell Station

Authority: IC 13-14-8; IC 13-17-3-4; IC 13-17-3-11

Sec. 26. (a) NIPSCo-Dean H. Mitchell Station in Lake County, source identification number 00117, shall meet the following requirements and emission limits for boiler numbers 4, 5, 6, and 11:

(1) Operation under either subdivision (2)(B) or (2)(C) shall only be allowed provided that a nozzle is in the stack serving boiler numbers 4 and 5 such that the stack diameter is restricted to eight and three-tenths (8.3) feet.
(2) NIPSCo may operate under any one (1) of the following scenarios:
1. (A) Boiler numbers 4, 5, 6, and 11 may operate simultaneously under the following conditions:
  1. (i) One (1) of boiler number 4 or 5 may operate on coal if the other boiler is operated on natural gas or is not operating. Particulate emissions from the stack serving boiler numbers 4 and 5 shall be limited to:
    1. (AA) one-tenth (0.1) pound per million Btu; and
    2. (BB) one hundred twenty-eight and seventy-five hundredths (128.75) pounds per hour.
  2. (ii) Boiler numbers 6 and 11 may operate simultaneously on coal. Particulate emissions from the stack serving boiler numbers 6 and 11 shall be limited to:
    1. (AA) one-tenth (0.1) pound per million Btu; and
    2. (BB) two hundred thirty-six (236.0) pounds per hour.
2. (B) Boiler numbers 4, 5, 6, and 11 may operate simultaneously on coal subject to the following conditions:
  1. (i) Particulate emissions from the stack serving boiler numbers 4 and 5 shall be limited to:
    1. (AA) seventy-four thousandths (0.074) pound per million Btu; and
    2. (BB) one hundred eighty-five (185.0) pounds per hour.
  2. (ii) Particulate emissions from the stack serving boiler numbers 6 and 11 shall be limited to:
    1. (AA) seventy-four thousandths (0.074) pound per million Btu; and
    2. (BB) one hundred seventy-five (175.0) pounds per hour.
3. (C) One (1) set of either boiler numbers 4 and 5 or 6 and 11 may operate on coal, if the other set is not operating, subject to the following conditions:
  1. (i) Particulate emissions from the stack serving boiler numbers 4 and 5 shall be limited to:
    1. (AA) one-tenth (0.1) pound per million Btu; and
    2. (BB) two hundred fifty (250.0) pounds per hour.
  2. (ii) Particulate emissions from the stack serving boiler numbers 6 and 11 shall be limited to:
    1. (AA) one-tenth (0.1) pound per million Btu; and
    2. (BB) two hundred thirty-six (236) pounds per hour.
(3) NIPSCo shall maintain a daily log of the following for boiler numbers 4, 5, 6, and 11:
1. (A) Fuel type.
2. (B) Transition time of changes between or within operating scenarios.
The log shall be maintained for a minimum of five (5) years and shall be made available to the department and U.S. EPA upon request.
(4) Emission limits shall be maintained during transition periods within or between operating scenarios.

(b) On and after May 13, 1999, biennial stack testing shall be conducted in the stack serving boiler numbers 4 and 5 and in the stack serving boiler numbers 6 and 11 meeting the following conditions:

(1) Stack testing shall:
1. (A) begin within sixty (60) days; and
2. (B) be completed within ninety (90) days of the initial use of the operating scenario specified in subsection (a)(2)(B).
Particulate emissions from boiler numbers 4, 5, 6, and 11 shall be limited to seventh-four thousandths (0.074) pound per million Btu.
(2) After the initial stack test specified in subdivision (1), NIPSCo may use the operating scenario specified in subsection (a)(2)(B) if in the previous biennial stack test particulate emissions from boiler numbers 4, 5, 6, and 11 met the emission limitation of seventy-four thousandths (0.074) pound per million Btu.
(3) If the operating scenario specified in subsection (a)(2)(B) has not been used since the previous biennial stack test specified in this subdivision, then particulate emissions from boiler numbers 4, 5, 6, and 11 shall be limited to one-tenth (0.1) pound per million Btu.
(4) If:
1. (A) the operating scenario specified in subsection (a)(2)(B) has been utilized since the previous biennial stack test specified in this subdivision; and
2. (B) NIPSCo no longer has the ability to operate the boilers as specified in subsection (a)(2)(B);
then particulate emissions from boiler numbers 4, 5, 6, and 11 shall be limited to one-tenth (0.1) pound per million Btu.

All emissions testing shall be conducted in accordance with the procedures specified in 326 IAC 3-6. Records of stack test data shall be maintained for a minimum of five (5) years and shall be made available to the department and U.S. EPA upon request.

(c) Units 5 and 6 shall comply with a twenty percent (20%), six (6) minute average opacity limit after December 10, 1993.

(d) The number 9A gas turbine shall fire natural gas only.

(Air Pollution Control Division; 326 IAC 6.8-2- 26; filed Aug 10, 2005, 1:00 p.m.: 28 IR 3518; filed Jan 23, 2008, 1:44 p.m.: 20080220-IR-326040279FRA; readopted filed Oct 18, 2024, 2:09 p.m.: 20241113-IR-326230809RFA)