(a) Except as provided in subdivision (b) of this section:

1. (1) any stationary, coal-fired boiler or stationary, coal-fired combustion turbine serving at any time, since the later of November 15, 1990 or the startup of the unit's combustion chamber, a generator with nameplate capacity of more than 25 MWe producing electricity for sale;
2. (2) if a stationary boiler or stationary combustion turbine that is not subject under paragraph (1) of this section, begins to combust coal or coal-derived fuel or to serve a generator with nameplate capacity of more than 25 MWe producing electricity for sale, the unit shall become applicable as provided in paragraph (1) of this section on the first date on which it both combusts coal or coal-derived fuel and serves such generator.

(b) The units that meet the requirements set forth in subparagraph (1)(i) or paragraph (2) of this subdivision shall not be subject to this Part:

1. (i) Any unit that is an applicable unit under subdivision (a) of this section:

   1. (a) qualifying as a cogeneration unit during the 12-month period starting on the date the unit first produces electricity and continuing to qualify as a cogeneration unit; and
   2. (b) not serving at any time, since the later of November 15, 1990 or the startup of the unit's combustion chamber, a generator with nameplate capacity of more than 25 MWe supplying in any calendar year more than one-third of the unit's potential electric output capacity or 219,000 MWh, whichever is greater, to any utility power distribution system for sale.
2. (ii) If a unit qualifies as a cogeneration unit during the 12-month period starting on the date the unit first produces electricity and meets the requirements of subparagraph (i) of this paragraph for at least one calendar year, but subsequently no longer meets all such requirements, the unit shall become an applicable unit starting on the earlier of January 1 after the first calendar year during which the unit first no longer qualifies as a cogeneration unit or January 1 after the first calendar year during which the unit no longer meets the requirements of subparagraph (i)(b) of this paragraph.

3. (2) Any unit that is an applicable unit under paragraph (a)(1) or (2) of this section, and is a solid waste incineration unit combusting municipal waste, and is subject to the requirements of:

   1. (i) a State Plan approved by the administrator in accordance with subpart Cb of part 60 of 40 CFR (emissions guidelines and compliance times for certain large municipal waste combustors);
   2. (ii) subpart Eb of part 60 of 40 CFR (standards of performance for certain large municipal waste combustors);
   3. (iii) subpart AAAA of part 60 of 40 CFR (standards of performance for certain small municipal waste combustors);
   4. (iv) a State Plan approved by the administrator in accordance with subpart BBBB of part 60 of 40 CFR (emission guidelines and compliance times for certain small municipal waste combustion units);
   5. (v) subpart FFF, of part 62 of 40 CFR (Federal Plan requirements for certain large municipal waste combustors); or
   6. (vi) subpart JJJ of part 62 of 40 CFR (Federal Plan requirements for certain small municipal waste combustion units).

(1)