San Luis Obispo County APCD 213-1 8/10/93

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

A. APPLICABILITY

This Rule specifies the provisions by which emissio n increases, emission reductions, and profile checks for offsets shall be calculated. Em ission 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 woul d apply for new emissions units.

B. POTENTIAL TO EMIT

The potential to emit is an emission limit which sp ecifies the maximum quantity of each air pollutant which may be emitted by an emission u nit during a 12 calendar month rolling period. This limit shall be based on any p eriod of 12 consecutive calendar months and shall be expressed in the units of tons per yea r. The potential to emit shall be calculated based on the maximum design capacity or other operating conditions which reflect the maximum potential emissions, unless spe cific limiting conditions on the Authority to Construct and/or Permit to Operate res trict emissions to a lower level.

C. ACTUAL EMISSIONS

The actual emissions of air pollutants from an emis sion 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 th ree years immediately preceding the date of application to bank emission reduction cred its, or a more representative period, as determined by the Air Pollution Control Officer (AP CO), of three consecutive years during the five years immediately preceding the dat e of such application. Actual emissions shall be expressed in the units of tons p er year. In no case shall the actual emissions exceed the permitted emissions. If at an y time during the specified three year period that an emissions unit was operated in viola tion of any applicable federal, state or District law, rule, regulation, order, or permit co ndition, then the actual emissions shall be adjusted to reflect the level of emissions that wou ld have occurred if such violation did not occur. Permit conditions and permitted emissio ns shall only be applicable to emission units for which a Permit to Operate is req uired.

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 un it.

2. Emission increases from a modified or replacement e mission unit shall be calculated as, the emission unit's post-project pot ential to emit adjusted to reflect the application of the current control technology r equired under Rule 204.A minusSan Luis Obispo County APCD 213-2 8/10/93 the emission unit's pre-project potential to emit a djusted to reflect the application of the current control technology required under Ru le 204.A.

3. Emission increases from a relocated emission unit s hall be calculated as, the emission unit's potential to emit, at the new locat ion, adjusted to reflect the application of the current control technology requi red under Rule 204.A minus the emission unit's potential to emit, at the old locat ion, adjusted to reflect the application of the current control technology requi red under Rule 204.A.

4. Emissions increases from a modified emission unit w here the modification is made for the purpose of complying with regulatory r equirements shall be calculated as, the emission unit's post-project pot ential to emit minus the emission unit's pre-project potential to emit adjusted to re flect the application of the best control method to comply with the regulation curren tly 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 m odification of the emission unit for the purpose of reducing the emission of ai r pollutants and where there is no increase in throughput, the emission increase fo r any pollutants that are not controlled by the proposed controls shall be calcul ated as, the emission unit's post-project potential to emit minus the emission u nit's pre-project potential to

emit.

E. EMISSION REDUCTIONS CREDITS

1. Emission reductions which result from the applicati on of control equipment, a modified emission unit or the replacement of an emi ssion 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 em issions based on the same throughput level as the actual emissions.

2. Emission reductions which result from a reduction i n throughput for an emission unit shall be calculated as, the actual emissions m inus 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 cr edits 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 applicati on of control equipment, a modified emission unit or the replacem ent of an emission unit with a lower emitting emission unit shall be c alculated as the greater

of the values calculated as follows:San Luis Obispo County APCD 213-3 8/10/93 1) The emission reduction calculated pursuant to subse ction 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 i n throughput for an emission unit shall be calculated as the greater of the values calculated as

follows:

1) The emission reduction calculated pursuant to subse ction 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 t he proposed throughput level.

c. Emission reductions which result from the shutdown of an emissions unit shall be calculated as the greater of the two follo wing values:

1) The emission reduction calculated pursuant to subse ction 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 e mission 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 eligib le 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 c redits, which were used to obtain the Permit to Operate, to the c ommunity bank.

2) Second, to allow any remaining portion of the emiss ion reduction to be banked pursuant to Rule 211.San Luis Obispo County APCD 213-4 8/10/93

F. PROFILE CHECK FOR OFFSETS

1. The profile check for offsets applies to all applic ations that propose to use emission reduction credits or community bank credit s as offsets for emission

increases.

2. The procedure for determining if the credits are ac ceptable for use as offsets is as

follows:

a. For both the emission increase and the proposed off set, the percentage of yearly emissions shall be determined for each of th e four quarters which shall begin on January 1, April 1, July 1, and Octo ber 1.

b. For each quarter, the lower percentage value betwee n 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.