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Title V Permit Writer's Tips - Potential to Emit Limits

Many sources request limits on their potential emissions (i.e., potential to emit) to avoid being classified as a major source, or to avoid being subject to certain requirements. Such PTE limits must be practically enforceable in accordance with EPA's guidance entitled, "Guidance on Limiting Potential to Emit in New Source Permitting" (June 13, 1989) (Attachment 2).

Terminology Alert...

  • PTE limits are limits which are assumed by a source to avoid otherwise applicable requirements.
  • All other permit limits, including those which may limit a source's potential emissions, are not PTE limits for purposes of this section of the guidance

 A.  PTE Limits Are Applicable Requirements

If a source is subject to a PTE limit which was established before the Title V permit is issued, that limit is an applicable requirement and must be incorporated into the Title V permit (e.g., a PTE limit taken years ago in a minor NSR permit to avoid applicability of major NSR review). PTE limits also can be established newly in Title V permits (e.g., a PTE limit on HAPs to avoid applicability of a MACT standard).

In accordance with EPA policy , permit conditions establishing effective PTE limits must impose practically enforceable production or operational limit (e.g., hours of operation, raw materials used) in addition to practically enforceable emissions limits.

Example #14 

In this example, the source had taken, in a currently effective minor NSR permit, a PTE limit on sulfur dioxide (SO2) in order to remain below the major source threshold for PSD (in this case, 250 TPY). Sulfur dioxide is the only pollutant for which the source's PTE would have been greater than 250 TPY without this limit. The source's Title V permit contains the following emission and operational limitations:

Emission Units 001, 002, 003, 004 and 005 - No. 6 fuel oil fired boilers:

1. Emission Limitation

A. The emissions of sulfur dioxide for all five (5) boilers shall not exceed 250 tons in any consecutive twelve (12) month period. [45CSR13, permit # 12345, January 21, 1993, condition #1].

2. Operational Limitation

A. Total combined No. 6 fuel oil usage for all five (5) boilers shall not exceed 5,926,273 gallons in any rolling twelve (12) month period. [45CSR13, permit #12345, January 21, 1993, condition #2].

B. The source shall burn only No. 6 fuel oil in each of the five (5) boilers. [45CSR13, permit #12345, January 21, 1993, condition #3].

In the Statement of Basis, the permit writer includes a calculation demonstrating that, based on the operational limit on gallons of No. 6 fuel oil burned, the maximum SO2 emissions are 220 TPY -- below the major
source limit of 250 TPY. The boilers are the only source of SO2 emissions at the facility.

The permit also requires monthly recordkeeping of the SO2 emissions, the 12-month rolling total SO2 emissions, fuel type/usage, and the 12-month rolling total of fuel burned.

B.  Documenting the Origin of PTE Limits 

Why did the source take this PTE limit?

The Statement of Basis should include an explanation of WHEN/WHY/HOW the PTE limit was originally established for the source.

 Example #15

The Statement of Basis explains the following information for a PTE limit:

Title V permit condition #10 contains a PTE limit on NOx emissions of 240 tons in any consecutive 12-month period. This limit was established in minor NSR permit #12345, issued June 3, 1991, for the purpose of avoiding major source status under the PSD program. NOx is the only pollutant for which the PTE (without this limit) would be greater than the major source threshold.

Permit condition # 15 establishes an associated operational limit on fuel usage (12- month rolling total) to ensure that the emissions limit will be met. [Include calculation to demonstrate that maximum emissions based on the fuel usage limit is equal 240 TPY].

Permit conditions #20, 21 and 22 contain the associated monitoring, recordkeeping, and reporting requirements to assure that the limit is practically enforceable.

[Additional description of monitoring, recordkeeping and reporting requirements].

C.  Permit Application Checklist

On EPA's Permit Application Checklist form (Attachment 3), Item #7 asks if PTE limits apply to the source. Please check "yes" to this question only if the source is subject to "true" PTE limits -- that is, limits that are designed to avoid major source status or the applicability of any requirements. Many types of emission limits (e.g., SIP limits, such as RACT) effectively serve to limit a source's potential emissions, but are not designed to escape major source status or applicable requirements. EPA Region III uses the information on this checklist to decide whether to target the permit for review.

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