Unless specifically defined in the Texas Clean Air Act (TCAA) or in the rules of the commission, the terms used by the commission have the meanings commonly ascribed to them in the field of air pollution control. In addition to the terms that are defined by the TCAA, and in §101.1 of this title (relating to Definitions), the following words and terms, when used in Subchapter B, Divisions 5 and 6 of this chapter (relating to Nonattainment Review Permits and Prevention of Significant Deterioration Review); and Subchapter C, Division 1 of this chapter (relating to Plant-Wide Applicability Limits), have the following meanings, unless the context clearly indicates otherwise.     
       (1) Actual emissions--Actual emissions as of a particular date are equal to the average rate, in tons per year, at which the unit actually emitted the pollutant during the 24-month period that precedes the particular date and that is representative of normal source operation, except that this definition shall not apply for calculating whether a significant emissions increase has occurred, or for establishing a plant-wide applicability limit. Instead, paragraph (3) of this section relating to baseline actual emissions shall apply for this purpose. The executive director shall allow the use of a different time period upon a determination that it is more representative of normal source operation. Actual emissions shall be calculated using the unit's actual operating hours, production rates, and types of materials processed, stored, or combusted during the selected time period. The executive director may presume that the source-specific allowable emissions for the unit are equivalent to the actual emissions, e.g., when the allowable limit is reflective of actual emissions. 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.      
       (2) Allowable emissions--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 that restrict the operating rate, or hours of operation, or both), and the most stringent of the following:                (A) the applicable standards specified in 40 Code of Federal Regulations Part 60 or 61;                 (B) the applicable state implementation plan emissions limitation including those with a future compliance date; or                 (C) the emissions rate specified as a federally enforceable permit condition including those with a future compliance date.        
       (3) Baseline actual emissions--The rate of emissions, in tons per year, of a federally regulated new source review pollutant.                (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 pollutant during any consecutive 24-month period selected by the owner or operator within the five-year period immediately preceding when the owner or operator begins actual construction of the project. The executive director shall allow the use of a different time period upon a determination that it is more representative of normal source operation.                 (B) For an existing facility (other than an electric utility steam generating unit), baseline actual emissions means the average rate, in tons per year, at which the facility actually emitted the pollutant during any consecutive 24-month period selected by the owner or operator within the ten-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 for a permit. The 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 with the exception of those required under 40 Code of Federal Regulations Part 63, had such major stationary source been required to comply with such limitations during the consecutive 24-month period.                 (C) For a new facility, the baseline actual emissions for purposes of determining the emissions increase that will result from the initial construction and operation of such unit shall equal zero; and for all other purposes during the first two years following initial operation, shall equal the unit's potential to emit.                 (D) The actual average rate shall be adjusted downward to exclude any non-compliant emissions that occurred during the consecutive 24-month period. For each regulated new source review pollutant, when a project involves multiple facilities, only one consecutive 24-month period must be used to determine the baseline actual emissions for the facilities being changed. A different consecutive 24-month period can be used for each regulated new source review pollutant. The average rate shall not be based on any consecutive 24-month period for which there is inadequate information for determining annual emissions, in tons per year, and for adjusting this amount. Baseline emissions cannot occur prior to November 15, 1990.                 (E) The actual average emissions rate shall include fugitive emissions to the extent quantifiable. Until March 1, 2016, emissions previously demonstrated as resulting from planned maintenance, startup, or shutdown activities; historically unauthorized; and subject to reporting under Chapter 101 of this title (relating to General Air Quality Rules) shall be included to the extent that they have been authorized, or are being authorized.        
       (4) Basic design parameters--For a process unit at a steam electric generating facility, the owner or operator may select as its basic design parameters either maximum hourly heat input and maximum hourly fuel consumption rate or maximum hourly electric output rate and maximum steam flow rate. When establishing fuel consumption specifications in terms of weight or volume, the minimum fuel quality based on British thermal units content shall be used for determining the basic design parameters for a coal-fired electric utility steam generating unit. The basic design parameters for any process unit that is not at a steam electric generating facility are maximum rate of fuel or heat input, maximum rate of material input, or maximum rate of product output. Combustion process units will typically use maximum rate of fuel input. For sources having multiple end products and raw materials, the owner or operator shall consider the primary product or primary raw material when selecting a basic design parameter. The owner or operator may propose an alternative basic design parameter for the source's process units to the executive director if the owner or operator believes the basic design parameter as defined in this paragraph is not appropriate for a specific industry or type of process unit. If the executive director approves of the use of an alternative basic design parameter, that basic design parameter shall be identified and compliance required in a condition in a permit that is legally enforceable.                (A) The owner or operator shall use credible information, such as results of historic maximum capability tests, design information from the manufacturer, or engineering calculations, in establishing the magnitude of the basic design parameter.                 (B) If design information is not available for a process unit, the owner or operator shall determine the process unit's basic design parameter(s) using the maximum value achieved by the process unit in the five-year period immediately preceding the planned activity.                 (C) Efficiency of a process unit is not a basic design parameter.        
       (5) Begin actual construction--In general, initiation of physical on-site construction activities on an emissions unit that 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 that mark the initiation of the change.      
       (6) Building, structure, facility, or installation--All of the pollutant-emitting activities that belong to the same industrial grouping, are located in one or more contiguous or adjacent properties, and are under the control of the same person (or persons under common control). Pollutant-emitting activities are considered to be part of the same industrial grouping if they belong to the same "major group" (i.e., that have the same two-digit code) as described in the Standard Industrial Classification Manual, 1972, as amended by the 1977 supplement.      
       (7) Carbon dioxide equivalent (CO               2              e) emissions--shall represent an amount of greenhouse gases (GHGs) emitted, and shall be computed by multiplying the mass amount of emissions in tons per year (tpy) for the GHGs, as defined in §101.1 of this title (relating to Definitions), by the gas's associated global warming potential as published in 40 Code of Federal Regulations Part 98, Subpart A, Table A-1 - Global Warming Potentials, and summing the resultant values.      
       (8) Clean coal technology--Any technology, including technologies applied at the precombustion, combustion, or post-combustion stage, at a new or existing facility that will achieve significant reductions in air emissions of sulfur dioxide or oxides of nitrogen associated with the utilization of coal in the generation of electricity, or process steam that was not in widespread use as of November 15, 1990.      
       (9) Clean coal technology demonstration project--A project using funds appropriated under the heading "Department of Energy-Clean Coal Technology," up to a total amount of $2.5 billion for commercial demonstration of clean coal technology, or similar projects funded through appropriations for the United States Environmental Protection Agency. The federal contribution for a qualifying project shall be at least 20% of the total cost of the demonstration project.      
       (10) Commence--As applied to construction of a major stationary source or major modification, means that the owner or operator has all necessary preconstruction approvals or permits and either has:                (A) begun, or caused to begin, a continuous program of actual on-site construction of the source, to be completed within a reasonable time; or                 (B) entered into binding agreements or contractual obligations, which cannot be canceled or modified without substantial loss to the owner or operator, to undertake a program of actual construction of the source to be completed within a reasonable time.        
       (11) Construction--Any physical change or change in the method of operation (including fabrication, erection, installation, demolition, or modification of an emissions unit) that would result in a change in actual emissions.      
       (12) Contemporaneous period--For major sources the period between:                (A) the date that the increase from the particular change occurs; and                 (B) 60 months prior to the date that construction on the particular change commences.        
       (13)               De minimis              threshold test (netting)--A method of determining if a proposed emission increase will trigger nonattainment or prevention of significant deterioration review. The summation of the proposed project emission increase in tons per year with all other creditable source emission increases and decreases during the contemporaneous period is compared to the significant level for that pollutant. If the significant level is exceeded, then prevention of significant deterioration and/or nonattainment review is required.      
       (14) Electric utility steam generating unit--Any steam electric generating unit that is constructed for the purpose of supplying more than one-third of its potential electric output capacity and more than 25 megawatts electrical output to any utility power distribution system for sale. Any steam supplied to a steam distribution system for the purpose of providing steam to a steam-electric generator that would produce electrical energy for sale is included in determining the electrical energy output capacity of the affected facility.      
       (15) Federally regulated new source review pollutant--As defined in subparagraphs (A) - (E) of this paragraph:                (A) any pollutant for which a national ambient air quality standard has been promulgated and any constituents or precursors for such pollutants identified by the United States Environmental Protection Agency;                 (B) except for greenhouse gases, any pollutant that is subject to any standard promulgated under Federal Clean Air Act (FCAA), §111;                 (C) any Class I or II substance subject to a standard promulgated under or established by FCAA, Title VI;                 (D) any pollutant that otherwise is subject to regulation under the FCAA; except that any or all hazardous air pollutants either listed in FCAA, §112 or added to the list under FCAA, §112(b)(2), which have not been delisted under FCAA, §112(b)(3), are not regulated new source review pollutants unless the listed hazardous air pollutant is also regulated as a constituent or precursor of a general pollutant listed under FCAA, §108; or                 (E) greenhouse gases that meet or exceed the thresholds established in §116.164 of this title (relating to Prevention of Significant Deterioration Applicability for Greenhouse Gases Sources).        
       (16) Greenhouse gases (GHGs)--as defined in §101.1 of this title (relating to Definitions).      
       (17) Lowest achievable emission rate--For any emitting facility, that rate of emissions of a contaminant that does not exceed the amount allowable under applicable new source performance standards promulgated by the United States Environmental Protection Agency under 42 United States Code, §7411, and that reflects the following:               Cont'd...