Administrative Rules of Montana › Department 17 - ENVIRONMENTAL QUALITY › Chapter 17.8 - AIR QUALITY › Subchapter 17.8.9 - Permit Requirements for Major Stationary Sources or Major Modifications Locating Within Nonattainment Areas › Rule 17.8.906 - BASELINE FOR DETERMINING CREDIT FOR EMISSIONS AND AIR QUALITY OFFSETS

Current through Register Vol. 13, July 5, 2024
(1) Pursuant to section 7503 of the FCAA,
				emission offsets in nonattainment areas are required to be in the form of, and
				against, actual emissions. Actual emissions preceding the filing of the
				application to construct or modify a source are the baseline for determining
				credit for emission and air quality offsets, as determined in compliance with
				this subchapter.
(2) Where the
				emission limitation under the Montana State Implementation Plan allows greater
				emissions than the actual emissions of the source, emission offset credit will
				be allowed only for control below the actual emissions.
(3) For an existing fuel combustion source,
				credit shall be based on the actual emissions for the type of fuel being burned
				at the time the application to construct is filed. If the existing source
				commits to switch to a cleaner fuel at some future date, emissions offsets
				credit based on the actual emissions for the fuels involved is not acceptable,
				unless the Montana air quality permit is conditioned to require the use of a
				specified alternative control measure which would achieve the same degree of
				emissions reduction should the source switch back to a dirtier fuel at some
				later date. The department shall ensure that adequate long-term supplies of the
				new fuel are available before granting emissions offset credit for fuel
				switches.
(4) Emission reductions
				achieved by shutting down an existing source or curtailing production or
				operating hours below baseline levels may be generally credited if such
				reductions are permanent, quantifiable, and federally enforceable, and if the
				area has an EPA-approved attainment plan. In addition, the shutdown or
				curtailment is creditable only if it occurred on or after the date specified
				for this purpose in the Montana State Implementation Plan, and if such date is
				on or after the date of the most recent emissions inventory used in the plan's
				demonstration of attainment. Where the plan does not specify a cutoff date for
				shutdown credits, the date of the most recent emissions inventory or attainment
				demonstration, as the case may be, shall apply. However, in no event may credit
				be given for shutdowns which occurred prior to August 7, 1977. For purposes of
				this (4), the department may choose to consider a prior shutdown or curtailment
				to have occurred after the date of its most recent emissions inventory, if the
				inventory explicitly includes as current "existing" emissions the emissions
				from such previously shutdown or curtailed sources. Such reductions may be
				credited in the absence of an approved attainment demonstration only if the
				shutdown or curtailment occurred on or after the date the new source's air
				quality application is filed, or if the applicant can establish that the
				proposed new source is a replacement for the shutdown or curtailed source, and
				the cutoff date provisions described earlier in this (4) are
				observed.
(5) No emissions credit
				shall be allowed for replacing one hydrocarbon compound with another of lesser
				reactivity, except for those compounds listed in Table 1 of EPA's "Recommended
				Policy on Control of Volatile Organic Compounds" (42 FR 35314, July 8,
				1977).
(6) All emission reductions
				claimed as offset credit shall be federally enforceable.
(7) Emission offsets may only be obtained
				from the same source or other sources in the same nonattainment area, except
				that the department may allow the owner or operator of a proposed source to
				obtain such emission reductions in another nonattainment area if:
(a) the other nonattainment area has an equal
				or higher nonattainment classification for the same pollutant than the area in
				which the proposed source will locate; and
(b) emissions from the other nonattainment
				area contribute to a violation of a national ambient air quality standard in
				the nonattainment area in which the proposed source will locate.