Section 203.301  Lowest Achievable Emission Rate

a)         For any source, lowest achievable emission rate (LAER) will be the more stringent rate of emissions based on the following:

1)         The most stringent emission limitation which is contained in the implementation plan of any state for such class or category of stationary source, unless it is demonstrated that such limitation is not achievable; or

2)         The most stringent emission limitation which is achieved in practice by such a class or category of stationary source.  This limitation, when applied to a modification, means the lowest achievable emissions rate for the new or modified emissions units within the stationary source.  In no event shall the application of this term permit a proposed new or modified stationary source to emit any pollutant in excess of the amount allowable under an applicable new source performance standard adopted by United States Environmental Protection Agency (USEPA) pursuant to Section 111 of the Clean Air Act and made applicable in Illinois pursuant to Section 9.1 of the Act.

b)         The owner or operator of a new major stationary source shall demonstrate that the control equipment and process measures applied to the source will produce LAER.

c)         Except as provided in subsection (e) or (f) below, the owner or operator of a major modification shall demonstrate that the control equipment and process measures applied to the major modification will produce LAER.  This requirement applies to each emissions unit at which a net increase in emissions of the pollutant has occurred or would occur as a result of a physical change or change in the method of operation.

d)         The owner or operator shall provide a detailed showing that the proposed emission limitations constitute LAER.  Such demonstration shall include:

1)         A description of the manner in which the proposed emission limitation was selected, including a detailed listing of information resources,

2)         Alternative emission limitations, and

3)         Such other reasonable information as the Agency may request as necessary to determine whether the proposed emission limitation is LAER.

e)         If the owner or operator of a major stationary source (other than a source which emits or has the potential to emit 100 tons per year or more of volatile organic material or nitrogen oxides) located in an area classified as serious or severe nonattainment for ozone does not elect to provide internal offsets for a change at the source in accordance with Section 203.207(e) of this Part, such change shall be considered a major modification for purposes of this Part, but in applying this Section in the case of any such modification, the Best Available Control Technology (BACT), as defined in section 169 of the Clean Air Act, shall be substituted for the Lowest Achievable Emission Rate (LAER).  BACT shall be determined in accordance with policies and procedures published by USEPA.

f)         In the case of any major stationary source of volatile organic material or nitrogen oxides located in an area classified as serious or severe nonattainment for ozone which emits or has the potential to emit 100 tons per year or more of volatile organic material or nitrogen oxides, respectively, whenever any change at that source results in any increase (other than a de minimis increase) in emissions of volatile organic material or nitrogen oxides, respectively, from any discrete operation, unit, or other pollutant emitting activity at the source, such increase shall be considered a major modification for purposes of this Part, except that if the owner or operator elects to offset the increase by a greater reduction in emissions of volatile organic material or nitrogen oxides, respectively, from other operations, units or activities within the source at an internal offset ratio of at least 1.3 to 1, the requirements of this Section concerning LAER shall not apply.

(Source:  Amended at 22 Ill. Reg. 5674, effective March 10, 1998)