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Federal new source review regulations require that new major-emitting industrial facilities and major modifications of existing facilities that significantly increase emissions must obtain a permit before construction. These projects must include the best pollution-control technology available. The goal of new source review is to protect existing clean air, particularly in pristine scenic, historic, and natural areas.

The regulated new source review pollutants include the National Ambient Air Quality Standards (NAAQS) pollutants (also called criteria pollutants), greenhouse gases, sulfuric acid mist, hydrogen sulfide, and more. See the air pollutant pages for more information.

Baseline actual emissions

Baseline actual emissions are the adjusted average annual emissions that occurred during any consecutive 24-month period during the past 10 years (five years for an electric-utility steam generating unit).

Emissions must be:

  • Adjusted downward to reflect any equipment removal and any enforceable emission limitations effected after the selected 24 months
  • Adjusted upward to reflect new emission units that began operating after the selected 24 months.

Control efficiency: If you installed pollution-control equipment after the baseline period and are exceeding the required control efficiency, you still must use the permit or rule efficiency rate. However, if you choose to use the two most recent years for your baseline, you use the efficiency where it actually operated. You can’t raise the baseline to reflect a required efficiency that was lower than that actually achieved.

You are legally obliged to adjust the baseline down to reflect the operation of the controls. If your air permit does not include a specific control efficiency, the percentage should be practical, based on what the device should achieve based on whatever data is available.

Voluntary controls: Do not adjust the baseline up to account for using voluntary controls during the baseline period. If a source has been operating voluntary controls for the entire 10 years, the baseline reflects the operation of those controls. If a source that installed voluntary controls in 2018 chose 2015 and 2016 for the baseline, then the baseline does not include the voluntary controls. If they are now required controls, the 2015-2016 baseline would be adjusted down to reflect their operation.

New equipment: The baseline actual emissions for a new unit that has not begun normal operation (still in the shakedown period) is zero. The baseline once it begins operation, but has operated less than 24 months, is the potential to emit or allowable emissions.

For emissions units constructed prior to or during the baseline period but did not operate during it, the baseline actual emissions are the average actual emissions during the baseline period, or zero.

Actual-to-projected-actual applicability test

If your project involves changing an existing emissions unit, determine the emissions increase by comparing baseline actual emissions to projected actual emissions during the five or 10 years following the change. Projected actual emissions should be based on pre-existing information that was prepared for business-related purposes, not just for purposes of the applicability test. Examples would be a stockholder prospectus, a letter to a parent company, applications for business loans, internal capital equipment requisition requests, other internal planning documents, etc. The projections cannot be prepared just for the purpose of the permit application. If a company can't provide non-permit related documentation of future activities, then they must use the past-actual-to-future-potential method of calculation.

This test does not apply to construction of new emissions units. In that case, determine the emissions increase by comparing baseline actual emissions to future potential emissions.

Projected actual emissions may exclude any increases that the emissions unit could accommodate before the change, and that are unrelated to the change (for example, demand growth).

Startup/shutdown/malfunction emissions. Startup/shutdown/malfunction emissions are included in baseline and projected emissions if those emissions were not non-compliant. In some cases, these emissions are allowed by the applicable requirement, so they count towards baseline and projected actual emissions. If they aren’t permissible, they don’t count on either side of the equation. The goal is to get an “apples to apples” comparison.

Applicability analysis and permit limits. Permit limits that companies took on a modification to avoid new source review can't be modified or removed using the actual-to-projected-actual test. The test for relaxing a limit would be done using the rule that applied at the time of the project. The actual-to-projected-actual test could be used if the unit were modified — constituting a new project.

Control devices not in rule. Facilities that add control devices that are not listed in the Minnesota Control Equipment Rule (Minn. R. 7011.0070) won't get credit for their operation when calculating actual emissions for new source review. Credit can only be taken for controls that are already required by a permit or subject to the control equipment rule.

Permit not needed? After doing an actual-to-actual test, some facilities determine that no permit is needed. In that case, the full potential to emit (PTE) is allowed (absent any permit restrictions), even if projected actuals are significantly less. If PTE = 300 and projected actuals = 165, allowable is 300 for all other purposes other than deciding if a specific modification triggers a new source review. A new source review maybe should have been triggered if the unit emits more than 165, but maybe not. Contact the MPCA to review.

Confidential business information. Business operators must estimate business activity for up to 10 years to determine projected actual emissions, and this information is public data and cannot be classified confidential. The alternative is using the traditional potential-to-actual test for new source review applicability.

Recordkeeping and reporting. Recordkeeping should consist of actual emissions for the units where projected future actual emissions were used in the calculations, and potential emissions for the units where potential emissions were used as the estimate. Reporting is required when the combination of actual emissions plus potential emissions exceed the significant increase level.

Plantwide applicability limit

A plantwide applicability limit (PAL) is an emissions limit based on all of a facility's actual emissions of a specific pollutant, including insignificant or conditionally insignificant activities. If facility emissions are kept below a plantwide actual emissions cap (that is, an actual PAL), the facility can avoid the major new source review permitting process or going through a netting review when changing the facility. Changes under the PAL are not exempt from state permitting requirements.

Under the PAL, emissions must be monitored at all emissions units and recordkeeping, monitoring, and reporting is required. Learn more:

State oversight. When renewing a PAL, the state can choose to reduce the limit based on criteria in federal rules. The state must explain its reasons for the adjustment.

Ambient air impacts analysis. The PAL doesn't directly require an ambient air impacts analysis, but no PAL can cause or contribute to the violation of an ambient standard (including increment and air quality-related values).

Synthetic minor limits. Under a PAL, states can remove previous synthetic minor limits, but there is no requirement to remove them. The preamble says “your reviewing authority should make sure that you are meeting all other regulatory requirements and that the removal of the limits does not adversely impact the NAAQS or PSD increments.” Some previous limits may need to remain in order to make the PAL enforceable (for example, requirements to operate controls at specific efficiencies).