NR 405.02(1)(c)(c) For any emissions unit that has not begun normal operations on the particular date, actual emissions shall equal the potential to emit of the unit on that date.

NR 405.02(2)(2) “Allowable emissions” means the emissions rate of a stationary source calculated using the maximum rated capacity of the source, unless the source is subject to federally enforceable limits which restrict the operating rate, or hours of operation, or both, and the most stringent of the following:

NR 405.02(2m)(2m) “Baseline actual emissions” means the rate of emissions, in tons per year, of a regulated NSR air contaminant, as determined in accordance with pars. (a) to (d).

NR 405.02(2m)(a)(a) For any existing electric utility steam generating unit, baseline actual emissions means the average rate, in tons per year, at which the unit actually emitted the air contaminant during any consecutive 24-month period selected by the owner or operator within the 5-year period immediately preceding when the owner or operator begins actual construction of the project. The department shall allow the use of a different time period upon a determination that it is more representative of normal source operation.

NR 405.02(2m)(a)2.2. The average rate shall be adjusted downward to exclude any emissions in excess of an emission limitation that was legally enforceable during the consecutive 24-month period.

NR 405.02(2m)(a)3.3. For a regulated NSR air contaminant, when a project involves multiple emissions units, only one consecutive 24-month period may be used to determine the baseline actual emissions for the emissions units being changed. A different consecutive 24-month period may be used for each regulated NSR air contaminant.

NR 405.02(2m)(a)4.4. The average rate may not be based on any consecutive 24-month period for which there is inadequate information for determining annual emissions, in tons per year, or for adjusting this amount if required by subd. 2.

NR 405.02(2m)(b)(b) For an existing emissions unit, other than an electric utility steam generating unit, baseline actual emissions means the average rate, in tons per year, at which the emissions unit actually emitted the air contaminant during any consecutive 24-month period selected by the owner or operator within the 10-year period immediately preceding either the date the owner or operator begins actual construction of the project, or, the date a complete permit application is received by the department for a permit required under ch. NR 406 or for a permit revision under ch. NR 407, whichever is earlier, except that the 10-year period may not include any period earlier than November 15, 1990.

NR 405.02(2m)(b)2.2. The average rate shall be adjusted downward to exclude any emissions in excess of an emission limitation that was legally enforceable during the consecutive 24-month period.

NR 405.02(2m)(b)3.3. The average rate shall be adjusted downward to exclude any emissions that would have exceeded an emission limitation with which the major stationary source must currently comply, had the major stationary source been required to comply with the limitation during the consecutive 24-month period. However, if an emission limitation is part of a maximum achievable control technology standard that the administrator proposed or promulgated under 40 CFR part 63, the baseline actual emissions need only be adjusted if the state has taken credit for the emissions reductions in an attainment demonstration or maintenance plan consistent with the requirements of s. NR 408.06 (9).

NR 405.02(2m)(b)4.4. For a regulated NSR air contaminant, when a project involves multiple emissions units, only one consecutive 24-month period may be used to determine the baseline actual emissions for the emissions units being changed. A different consecutive 24-month period may be used for each regulated NSR air contaminant.

NR 405.02(2m)(b)5.5. The average rate may not be based on any consecutive 24-month period for which there is inadequate information for determining annual emissions, in tons per year, or for adjusting this amount if required by subds. 2. and 3.

NR 405.02(2m)(c)(c) For a new emissions unit, the baseline actual emissions for purposes of determining the emissions increase that will result from the initial construction and operation of the unit shall equal zero; and thereafter, for all other purposes, shall equal the unit’s potential to emit.

NR 405.02(2m)(d)(d) For a PAL for a stationary source, the baseline actual emissions shall be calculated for existing electric utility steam generating units in accordance with the procedures contained in par. (a), for other existing emissions units in accordance with the procedures contained in par. (b), and for a new emissions unit, in accordance with the procedures contained in par. (c).

NR 405.02(3)(3) “Baseline area” means any intrastate area, and every part thereof, designated as attainment or unclassifiable under section 107 (d) (1) (A) (ii) or (iii) of the Act (42 USC 7407 (d) (1) (A) (ii) or (iii)) in which the major source or major modification establishing the minor source baseline date would construct or would have an air quality impact for the pollutant for which the baseline date is established equal to or greater than 1 µg/m3 (annual average) for SO2, NO2, or PM10, or equal to or greater than 0.3mg/m3 (annual average) for PM2.5. Area redesignations under section 107 (d) (1) (A) (ii) or (iii) of the Act (42 USC 7407 (d) (1) (A) (ii) or (iii)) cannot intersect or be smaller than the area of impact of any major stationary source or major modification which either establishes a minor source baseline date or is subject to this chapter.

NR 405.02(4)(a)(a) “Baseline concentration” means that ambient concentration level which exists in the baseline area at the time of the applicable minor source baseline date. A baseline concentration is determined for each air contaminant for which a minor source baseline date is established and shall include:

NR 405.02(4)(a)2.2. The allowable emissions of major stationary sources which commenced construction before the major source baseline date, but were not in operation by the applicable minor source baseline date.

NR 405.02(6)(6) “Begin actual construction” means, in general, initiation of physical on-site construction activities on an emissions unit which are of a permanent nature. Such activities include, but are not limited to, installation of building supports and foundations, laying of underground pipework and construction of permanent storage structures. With respect to a change in method of operation, this term refers to those on-site activities, other than preparatory activities, which mark the initiation of the change.