SAN LUIS OBISPO COUNTY AIR POLLUTION CONTROL DISTRICT

RULE 213 - CALCULATIONS
(Adopted 11/5/91; Revised 8/10/93)

A. APPLICABILITY

This Rule specifies the provisions by which emission increases, emission reductions, and profile checks for offsets shall be calculated. Emission increases and emission reductions shall be calculated separately. Both the emission increase and emission decrease sections shall apply for many cases where an emissions unit is being replaced, modified, or relocated. Only the emission increase section would apply for new emissions units.

B. POTENTIAL TO EMIT

The potential to emit is an emission limit which specifies the maximum quantity of each air pollutant which may be emitted by an emission unit during a 12 calendar month rolling period. This limit shall be based on any period of 12 consecutive calendar months and shall be expressed in the units of tons per year. The potential to emit shall be calculated based on the maximum design capacity or other operating conditions which reflect the maximum potential emissions, unless specific limiting conditions on the Authority to Construct and/or Permit to Operate restrict emissions to a lower level.

C. ACTUAL EMISSIONS

The actual emissions of air pollutants from an emission unit shall be calculated based on the actual operating history of the emission unit. The actual operating history of the emission unit shall be averaged over a period of three years immediately preceding the date of application to bank emission reduction credits, or a more representative period, as determined by the Air Pollution Control Officer (APCO), of three consecutive years during the five years immediately preceding the date of such application. Actual emissions shall be expressed in the units of tons per year. In no case shall the actual emissions exceed the permitted emissions. If at any time during the specified three year period that an emissions unit was operated in violation of any applicable federal, state or District law, rule, regulation, order, or permit condition, then the actual emissions shall be adjusted to reflect the level of emissions that would have occurred if such violation did not occur. Permit conditions and permitted emissions shall only be applicable to emission units for which a Permit to Operate is required.

D. EMISSION INCREASES

  1. Emission increases from the addition of an emission unit shall be calculated by using the potential to emit for the new emission unit.
  2. Emission increases from a modified or replacement emission unit shall be calculated as, the emission unit's post-project potential to emit adjusted to reflect the application of the current control technology required under Rule 204.A minus the emission unit's pre-project potential to emit adjusted to reflect the application of the current control technology required under Rule 204.A.
  3. Emission increases from a relocated emission unit shall be calculated as, the emission unit's potential to emit, at the new location, adjusted to reflect the application of the current control technology required under Rule 204.A minus the emission unit's potential to emit, at the old location, adjusted to reflect the application of the current control technology required under Rule 204.A.
  4. Emissions increases from a modified emission unit where the modification is made for the purpose of complying with regulatory requirements shall be calculated as, the emission unit's post-project potential to emit minus the emission unit's pre-project potential to emit adjusted to reflect the application of the best control method to comply with the regulation currently available, as determined by the APCO.
  5. For a modified emission unit where the modification consists of the voluntary application of control equipment or the voluntary modification of the emission unit for the purpose of reducing the emission of air pollutants and where there is no increase in throughput, the emission increase for any pollutants that are not controlled by the proposed controls shall be calculated as, the emission unit's post-project potential to emit minus the emission unit's pre-project potential to emit.

E. EMISSION REDUCTIONS CREDITS

  1. Emission reductions which result from the application of control equipment, a modified emission unit or the replacement of an emission unit with a lower emitting emission unit shall be calculated as, the emission unit's pre-project actual emissions minus the emission unit's post-project emissions based on the same throughput level as the actual emissions.
  2. Emission reductions which result from a reduction in throughput for an emission unit shall be calculated as, the actual emissions minus the new potential to emit at the proposed throughput level.
  3. Emission reductions which result from the shutdown of an emission unit shall be calculated as the actual emissions.
  4. If emission reduction credits, or community bank credits were provided as offsets after November 5, 1991 for the purpose of obtaining a Permit to Operate, emission reductions shall be calculated as follows:

    a. Emission reductions which result from the application of control equipment, a modified emission unit or the replacement of an emission unit with a lower emitting emission unit shall be calculated as the greater of the values calculated as follows:

    1. The emission reduction calculated pursuant to subsection E.1.
    2. The lesser of the two following values:

      i. The total amount of all emission reduction credits and community bank credits provided as offsets since November 5, 1991.

      ii. The emission units's pre-project potential to emit minus the emission units's post-project potential to emit.

    b. Emission reductions which result from a reduction in throughput for an emission unit shall be calculated as the greater of the values calculated as follows:
    1. The emission reduction calculated pursuant to subsection E.2.
    2. The lesser of the two following values:

      i. The total amount of all emission reduction credits and community bank credits, provided as offsets since November 5, 1991.

      ii. The emission units's pre-project potential to emit minus the emission unit's post-project potential to emit at the proposed throughput level.

    c. Emission reductions which result from the shutdown of an emissions unit shall be calculated as the greater of the two following values:
    1. The emission reduction calculated pursuant to subsection E.3.
    2. The total amount of all emission reduction credits and community bank credits provided as offsets since November 5, 1991.
    d. For the purpose of determining the portion of any emission reduction calculated pursuant to subsections E.4.a, E.4.b, or E.4.c, which shall be returned to the community bank, or shall be eligible for banking pursuant to Rule 211, the following procedure shall be used. The emission reduction shall be applied:
    1. First, to return any community emission reduction credits, which were used to obtain the Permit to Operate, to the community bank.
    2. Second, to allow any remaining portion of the emission reduction to be banked pursuant to Rule 211.

F. PROFILE CHECK FOR OFFSETS

  1. The profile check for offsets applies to all applications that propose to use emission reduction credits or community bank credits as offsets for emission increases.
  2. The procedure for determining if the credits are acceptable for use as offsets is as follows:

    a. For both the emission increase and the proposed offset, the percentage of yearly emissions shall be determined for each of the four quarters which shall begin on January 1, April 1, July 1, and October 1.

    b. For each quarter, the lower percentage value between the emission increase and the proposed offset shall be summed.

    c. For the credits to be acceptable for offsets, this sum shall be equal to at least 80 percent.