SAN JOAQUIN VALLEY UNIFIED AIR POLLUTION CONTROL DISTRICT 

Appendix B: Emissions Reduction Analysis September 20, 2007 

Final Staff Report with Appendices for 

 Revised Proposed Amendments to Rule 4703

APPENDIX B 

Emissions Reduction Analysis for Revised 

Proposed Amendments to Rule 4703 (Stationary Gas Turbines) 

September 20, 2007 
SAN JOAQUIN VALLEY UNIFIED AIR POLLUTION CONTROL DISTRICT 

Appendix B: Emissions Reduction Analysis September 20, 2007 

 Final Staff Report with Appendices for 

 Revised Proposed Amendments to Rule 4703 

B-2

NOx EMISSIONS REDUCTION ANALYSIS 

Rule 4703 (Stationary Gas Turbines) 

I. SUMMARY 

District staff has estimated the NOx emissions reduction from stationary gas turbines 

that would comply with the proposed Tier 3 NOx emission limits of Rule 4703. About 74 

turbines (71 are less than ten (10) MW and 3 are 25 MW) would be subject to the 

proposed NOx limits. Some of the turbines are already in compliance with the proposed 

NOx limits and some are exempt from the NOx limits. Approximately 65 turbines would 

need to be retrofit, replaced or reduce their operating hours to comply with the proposed 

NOx limits. This appendix identifies the estimated NOx emissions reduction and outlines 

the methodology used to calculate the NOx emissions reduction for the proposed 

amendments to Rule 4703. 

The 2007 Ozone Plan indicated that for Stationary Gas Turbines (S-COM-5) the 2012 

baseline NOx emissions are about 5.1 tons per day and that a reduction of about 0.68 

tons of NOx per day is anticipated upon final implementation. The analysis indicates 

that the NOx emissions reduction from turbines due to the proposed amendments is 

approximately 786 tons per year (2.2 tons/day), which represents about 43 percent 

reduction. 

 

II. BACKGROUND 

The latest amendments to the NOx emission limits of Rule 4703 were in April 2002. 

For gas fueled units rated no more than 10 MW, the amendments of April 2002 

specified NOx emissions limits of 25 ppmvd to 50 ppmvd, at 15% O2. The 

amendments of April 2002 specified NOx emissions limits of 3 ppmvd to 25 ppmvd, at 

15% O2, for gas fueled units rated greater than 10 MW. 

This analysis estimates the NOx emissions reduction from gas fueled stationary gas 

turbines that would comply with the proposed NOx emission limits in Section 5.1.3 of 

Rule 4703. The proposed NOx limits are listed in the following table. 
SAN JOAQUIN VALLEY UNIFIED AIR POLLUTION CONTROL DISTRICT 

Appendix B: Emissions Reduction Analysis September 20, 2007 

 Final Staff Report with Appendices for 

 Revised Proposed Amendments to Rule 4703 

B-3

Table 1 Proposed NOx Compliance Limits 

NOx Compliance Limit, 

Turbine Classification Rating ppmvd at 15% O2

Gas Fuel Liquid Fuel 

a) Less than 3 MW. 9 25 

b) 3 MW to 10 MW pipeline gas turbine. 

8 during steady 

state and 

12 during nonsteady state 

25 

c) 3 MW to 10 MW and permit condition for less than 

877 hrs/yr operation. 9 25 

d) 3 MW to 10 MW and permit condition for 877 hrs/yr 

operation or greater. 5 25 

e) Greater than 10 MW, Simple cycle, and permit 

condition for no greater than 200 hrs/yr operation, 

except as provided in Section 5.1.3.3. 

25 42 

f) Greater than 10 MW, Simple cycle, and permit 

condition for greater than 200 hrs/yr operation but 

no greater than 877 hrs/yr operation. 

5 25 

District staff feels that the proposed Tier 3 NOx limits can be met through the use of 

SCR technology, combustion design technology or replacement units and that the 

cost of such technologies is reasonable. The proposed limits for the units no greater 

than 10 MW are not as stringent as the limits for larger units as the smaller units are 

usually not as efficient as the larger units. 

III. TURBINES AFFECTED BY PROPOSED NOX LIMITS 

In order to determine the NOx emissions reduction from the proposed amendments of 

this project, District staff identified the number of units that would be affected and 

pertinent operating characteristics of such units. The District’s Permits database was 

used to identify the units currently under permit. Based on the information in the 

database, District staff identified 74 turbines that could be subject to the proposed Tier 

3 NOx emission limits. Of the 74 turbines identified, two of the turbines are either 

exempt or dormant. Of the 72 active gas turbines that could be affected by the 

proposed Tier 3 NOx emission limits, seven (7) turbines are already in compliance 

with the proposed Tier 3 NOx emission limits, therefore, 65 turbines would need to 

take action to comply with the proposed emission limits. 
SAN JOAQUIN VALLEY UNIFIED AIR POLLUTION CONTROL DISTRICT 

Appendix B: Emissions Reduction Analysis September 20, 2007 

 Final Staff Report with Appendices for 

 Revised Proposed Amendments to Rule 4703 

B-4

IV. EMISSIONS REDUCTION ANALYSIS 

The expected NOx emissions reduction depends on the number of units in operation, 

the size of the units in operation, the annual operating hours of the units, the 

operating load of the units, and the level of emission control of the units. The permit 

database was also used to gather other information for the units such as unit 

manufacturer and model, heat input rating, NOx emission limit, control system and 

annual operating hours. The NOx emissions reduction analysis was performed as 

follows: 

A. Emissions Reduction Methodology 

The estimated current annual NOx emissions and the estimated potential annual NOx 

emissions were calculated using the following equation: 

NOx = LF x MMBtu/hr x HR x EF / 2,000 lb/ton 

Where: 

NOx = Current annual NOx emissions or Potential annual NOx 

emissions in tons/year 

LF = turbine load factor 

MMBtu/HR = heat input rating 

HR = annual hours of operation 

EF = NOx emission factor in pounds per MMBtu 

Where: 

EF = NOx emission factor in ppmv x 0.00366 

ppmv = NOx emissions in parts per million corrected to 15% oxygen 

0.00366 = Conversion factor used: 0.00366 lb/MMBtu per ppmv NOx 

The estimated annual NOx emissions reduction was calculated using the following 

equation: 

NOx Emissions Reduction = Current annual NOx emissions - Potential annual NOx 

 emissions. 

B. Sample Calculation 

Current NOx = LF x MMBtu/hr x HR x EF / 2,000 lb/ton 

= 0.75 x 40.9 x 7884 x (35 x 0.00366) / 2000 

 = 0.0424 tons/day 

Potential NOx = LF x MMBtu/hr x HR x EF / 2,000 lb/ton 

= 0.75 x 40.9 x 7884 x (9 x 0.00366) / 2000 

 = 0.0109 tons/day 
SAN JOAQUIN VALLEY UNIFIED AIR POLLUTION CONTROL DISTRICT 

Appendix B: Emissions Reduction Analysis September 20, 2007 

 Final Staff Report with Appendices for 

 Revised Proposed Amendments to Rule 4703 

B-5

Emissions Reduction = 365 x (Current NOx emissions - Potential NOx emissions) 

= 365 x (0.0424 tons/day - 0.0109 tons/day) 

 = 11.51 tons/year 

C. Assumptions for NOx Emissions Reduction Analysis 

The assumptions used in the NOx emissions reduction analysis are listed below. 

Unless otherwise noted, the listed assumptions apply to all turbines considered in the 

analysis. 

1. It was assumed that units would comply with the proposed limits and not be 

replaced with a different power source. 

2. It was assumed that units are operated at 75% of rated power. 

3. It was assumed, except for units referred to in Item 4 below, that turbines with an 

annual hours limit on their permit were available for the full amount of those hours 

and that other turbines were operated 90% of the year due to maintenance, etc. 

4. It was assumed that there would not be any emissions reduction from the three 

units greater than 10 MW, Simple cycle, and permit condition for no greater than 

877 hrs/yr operation as they would comply with the proposed amendments by 

modifying their permits to specify “no greater than 200 hrs/yr operation”. 
SAN JOAQUIN VALLEY UNIFIED AIR POLLUTION CONTROL DISTRICT 

Appendix B: Emissions Reduction Analysis September 20, 2007 

 Final Staff Report with Appendices for 

 Revised Proposed Amendments to Rule 4703 

B-6

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