PERMIT HANDBOOK

2.4.1 MicroTurbines (25-500 KW) by M.K. Carol Lee

August 6, 2008 Process Description This chapter is limited to microturbines firing natural gas. Microturbines are small combustion turbines that produce between 25 kW and 500 kW of power. A thorough explanation of general turbine technology is available from Chapter 3.1 (Stationary Gas Turbines) of AP-42 (Fifth Edition, Volume I). In addition, explanation of microturbine technology is available from the California Energy Commissions California Distributed Energy Resource Guide. Any turbine with a maximum output rating greater than 50 hp is subject to permitting requirements per Regulation 2-1-114.2.1. However, if the turbine is used solely for instructional purposes at research, teaching, or educational facilities, they may be exempt for Regulation 2-1-114.2.2. Completeness Determination The following District forms should be completed and fees provided for the microturbines. Use the Completeness Determination Checklist to verify completeness. Use the Data Form Guidance to ensure that the forms are completed correctly. Use the Fee Calculation Guidance to ensure that the fees are calculated accurately.1. Form 101-B (one for facility). 2. Form C (one per source). 3. If combustion products exhaust into add-on

abatement device, Form A (one per device).

4. If Health Risk Screening is triggered, Form HRSA (one per source).

5. Fees, calculated per Regulation 3 (Schedule B).

Emission CalculationsThe ideal hydrocarbon products of combustion in which a fossil fuel is burned are water vapor and carbon dioxide. All other products are considered pollutants, consisting mainly of NOx (Nitrogen Oxides), CO (Carbon Monoxide), POC (Precursor Organic Compounds in the form of unburned hydrocarbons), SOx (Sulfur Dioxide), and PM10 (Particulate Matter). Emission factors of criteria pollutants from turbines are usually based on California Air Resources Board (CARB) certified data for Distributed Generation for nitrogen oxides (NOx), carbon monoxide (CO), and precursor organic carbons (POC). Based on maximum Pacific Gas & Electric Natural Gas Specification for Sulfur of 1 grain per 100 standard cubic feet, PM10 (as (NH4)2SO4) and SO2 emission factors are calculated. The NPOC emission factor is based on Table 3.1-2a of AP-42.

Compound Emission

Factor Unit Reference NOx *** lb/MW-hr Distributed Generation Certification (ARB Executive Order DG-###) CO *** lb/MW-hr Distributed Generation Certification (ARB Executive Order DG-###) POC *** lb/MW-hr Distributed Generation Certification (ARB Executive Order DG-###) PM10 5.78E-03 lb/MMBtu Based on Max PG&E Natural Gas Specification for Sulfur of 1 gr/100 scf SO2 2.80E-03 lb/MMBtu Based on Max PG&E Natural Gas Specification for Sulfur of 1 gr/100 scf NPOC 8.90E-03 lb/MMBtu AP-42 Table 3.1-2a (April, 2000) Note: *** = Based on Distributed Generation Certification data PM10 = (1 gr/100 scf)(lb/7000 gr)(1/1020 BTU/scf)(1x10E6BTU/MMBTU)(132 lb (NH4)2SO4/32 lb S) PM10 = 0.00578 lb/MMBTU SO2 = (1 gr/100 scf)(lb/7000 gr)(1/1020 BTU/scf)(1x10E6BTU/MMBTU)(64 lb (NH4)2SO4/32 lb S) SO2 = 0.00280

4.1 MICROTURBINES 1

http://www.epa.gov/ttn/chief/ap42/ch03/final/c03s01.pdfhttp://www.epa.gov/ttn/chief/ap42/ch03/final/c03s01.pdfhttp://www.epa.gov/ttn/chief/ap42/index.htmlhttp://www.energy.ca.gov/distgen/equipment/microturbines/microturbines.htmlhttp://www.baaqmd.gov/dst/regulations/rg0201.pdfhttp://www.baaqmd.gov/dst/regulations/rg0201.pdfhttp://www.baaqmd.gov/pmt/handbook/rev02/PH_00_06_04.pdfhttp://www.baaqmd.gov/pmt/handbook/rev02/PH_00_06_02.pdfhttp://www.baaqmd.gov/pmt/handbook/rev02/PH_00_06_03.pdfhttp://www.baaqmd.gov/pmt/forms/p101b.dochttp://www.baaqmd.gov/pmt/forms/c_fuel_combustion_source.dochttp://www.baaqmd.gov/pmt/forms/a_abatement_device.dochttp://www.baaqmd.gov/pmt/forms/hrsa.dochttp://www.baaqmd.gov/pmt/forms/hrsa.dochttp://www.baaqmd.gov/dst/regulations/rg0300.pdfhttp://www.baaqmd.gov/pmt/handbook/rev02/PH_00_05_02_04_01_emitcalc.xlshttp://www.epa.gov/ttn/chief/ap42/ch03/final/c03s01.pdfhttp://www.epa.gov/ttn/chief/ap42/index.html

PERMIT HANDBOOK

Toxic Air Contaminant emissions from microturbines may be calculated using AP-42 Emission Factors from Table 3.1 for Uncontrolled Emission Factors for Stationary Natural Gas Turbines, unless there is actual source test data available.

Compound Emission

Factor Unit

Acute Trigger Level (lb/hr)

Chronic Trigger Level (lb/yr)

1,3-Butadiene 4.30E-07 Lb/MMBtu None 1.10E+00 Acetaldehyde 4.00E-05 Lb/MMBtu None 6.40E+01 Acrolein 6.40E-06 Lb/MMBtu 4.2E-04 2.30E+00 Benzene 1.20E-05 Lb/MMBtu 2.9E+00 6.40E+00 Ethylbenzene 3.20E-05 Lb/MMBtu None 7.70E+04 Formaldehyde 7.1E-04 Lb/MMBtu 2.1E-01 3.00E+01 Naphthalene 1.30E-06 Lb/MMBtu None None PAH 2.20E-06 Lb/MMBtu None 1.10E-02 Propylene Oxide 2.90E-05 Lb/MMBtu 6.8E+00 4.90E+01 Toluene 1.30E-04 Lb/MMBtu 8.2E+01 1.20E+04 Xylene 6.40E-05 Lb/MMBtu 4.9E+01 2.70E+04 Applicable Requirements District Rules and Regulations A microturbine is not subject to the requirements of Regulation 9-9, per Regulation 9-9-110, because it will typically have a power output less than 0.3 MW. A microturbine will be subject to and is expected to comply with the SO2 ground level concentration and general emission limitations of Regulation 9-1, because it will be fired on natural gas with a maximum sulfur content of 1 grain per 100 scf, which is the maximum PG&E natural gas specification for sulfur. New Source Performance Standards (NSPS)All stationary gas turbines with a heat input at peak load equal to or greater than 10.7 gigajoules (10 million Btu) per hour, based on the lower heating value of the fuel fired is subject to the Subpart GG of Part 60. However, a microturbine will typically not have that high a heat input to subject it to NSPS requirements. The permit engineer should review the microturbine application to confirm that the proposed microturbine is exempt from the NSPS. Best Available Control Technology (BACT)In general, a microturbine which has a CARB Distributed Generation certification (i.e., Executive Order DG-###) will not trigger a BACT review because criteria pollutant emissions will be less than 10 pounds per operating day. The permit engineer should review the microturbine application to ensure that the proposed microturbine does not trigger BACT review. If BACT is triggered, the permit engineer should conduct a BACT determination to ensure that the source meets BACT requirements. California Environmental Quality Act (CEQA)Permit applications which are reviewed following the specific procedures, fixed standards and objective measurements set forth in this chapter (2.4.1) are classified as ministerial and will accordingly be exempt from CEQA review per Regulation 2-1-311. In addition to the above-mentioned source-specific applicable requirements, other requirements may also be applicable depending on the facility, its application emissions, and its source location:

Offsets Prevention of Significant Deterioration

School Notification Risk Screening Analysis

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http://www.epa.gov/ttn/chief/ap42/ch03/final/c03s01.pdfhttp://www.baaqmd.gov/dst/regulations/rg0909.pdfhttp://www.baaqmd.gov/dst/regulations/rg0901.pdfhttp://ecfr.gpoaccess.gov/cgi/t/text/text-idx?c=ecfr&sid=c77854e103e55709c4339ba9a478456f&tpl=/ecfrbrowse/Title40/40cfr60_main_02.tplhttp://ecfr.gpoaccess.gov/cgi/t/text/text-idx?c=ecfr&sid=c4c1327512e4991d0343c5b691a000b1&rgn=div6&view=text&node=40:6.0.1.1.1.48&idno=40http://www.baaqmd.gov/dst/regulations/rg0201.pdf

PERMIT HANDBOOK

Permit Conditions As long as the microturbine has a CARB Distributed Generation certification (i.e., Executive Order DG-###), there are no permit conditions required. Because emission calculations for each microturbine are based upon 24 hour per day, 365 day per year operation, the permit will not require permit conditions to limit fuel use or specify recordkeeping.

4.1 MICROTURBINES 3

2.4.1 MicroTurbines (25-500 KW) Completeness Determination Emission Calculations Applicable Requirements District Rules and Regulations Permit Conditions