EPA Greenhouse Gas Reporting – Subpart W Fugitive methane emissions John Erickson, PE American...

EPA Greenhouse Gas Reporting – Subpart W

Fugitive methane emissions

John Erickson, PEAmerican Public Gas Association

EPA Greenhouse Gas Reporting – Subpart W

Fugitive methane emissions

John Erickson, PEAmerican Public Gas Association

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Purpose of this Webinar

• Summarize the fugitive emission estimating requirements of the rule

• Demonstrate how to use the APGA EXCEL spreadsheet calculator to determine if you are required to report under Subpart W

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Why Fugitive Methane?

• EPA believes that methane, the primary component of natural gas, is a greenhouse gas ~ 21 times more effective than carbon dioxide

• EPA wants an inventory of all greenhouse gas emissions

• No reductions are mandated at this time

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Reporting

• First reports are due March 30, 2012 for estimated emissions for calendar year 2011

• Reporting is on-line via the EPA’s E-GGRT system

• Utilities with estimated fugitive emissions plus combustion emissions over 25 thousand metric tons CO2 equivalent must report

• Estimates must be based on EPA’s emission factors, not actual emissions

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What to Report

• # of leaking meters, regulators, and associated equipment at above grade transmission-distribution transfer stations, including equipment leaks from connectors, block valves, control valves, pressure relief valves, orifice meters, regulators, and open ended lines.

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What to Report

• Estimated emissions from:– Below grade transmission-distribution transfer

stations.– Above grade metering-regulating station. – Below grade metering-regulating stations.– Mains– Services

• Complete list found at 98.236(a)(16) of the rule

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What to Report

• Also report under subpart W of this part the emissions of CO2, CH4, and N2O from stationary fuel combustion sources following the methods in §98.233(z).

• (z)(3) External fuel combustion sources with a rated heat capacity equal to or less than 5 mmBtu/hr do not need to report combustion emissions or include these emissions for threshold determination in §98.231(a).

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98.233(z) Methods

• CO2 = scf *0.001028 mmbtu/scf * 53.02 kgCO2/mmbtu * 0.001mt/kg

• CH4 = scf * mmbtu/scf * 0.001 kg CH4/mmbtu * 0.001 mt/kg * 21 mt CO2e/mtCH4

• N2O = scf * mmbtu/scf * 0.0001 kgN2O/mmbtu * 0.001 mt/kg * 310 mtCO2e/mt N2O

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Annual Leak Surveys Required

• At least once each year, check “TD transfer station” components for leaks

• “Transmission-distribution (TD) transfer station means a meter-regulating station where a local distribution company takes part or all of the natural gas from a transmission pipeline and puts it into a distribution pipeline.”

• This is the only actual measurement required for fugitive methane from distribution systems

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Important Definitions

• “Natural gas distribution means the distribution pipelines and metering and regulating equipment at metering- regulating city gate stations, and excluding customer meters, that physically deliver natural gas to end users and that are operated by a Local Distribution Company (LDC) within a single state.”

• “Metering-regulating station means a station that meters the flowrate, regulates the pressure, or both, of natural gas in a natural gas distribution facility. This does not include customer meters, customer regulators, or farm taps.”

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What is a leak?

• Measurement means determining, yes or no, if the equipment is leaking, not the volume of gas leaking

• 98.234 (a)(2) Method 21. Use the equipment leak detection methods in 40 CFR part 60, appendix A-7, Method 21. If using Method 21 monitoring, if an instrument reading of 10,000 ppm or greater is measured, a leak is detected.

• Method 21 includes HFI, CGI, etc.

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Example: Springfield, MO

• 5 TD Gate stations (owns meter runs at 1)• 31 BG M&R Stations 100-300 psig inlet• 81 BG M&R stations < 100 psig inlet• Mains:

– 418.69 miles protected steel– 838.57 miles plastic

• Services:– 13,951 protected steel– 62681 plastic

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Leaker Emission Factors

• Above Grade Transmission/distribution transfer stations– Connector = 1.72 cf/hr/count– Block Valve = 0.566 cf/hr/count– Control Valve = 9.48 cf/hr/count– Pressure Relief Valve = 0.274 cf/hr/count– Orifice Meter = 0.215 cf/hr/count– Regulator = 0.784 cf/hr/count– Open-ended Line = 26.533 cf/hr/count

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Leaker Emission Factors

• “If one leak detection survey is conducted, assume the component was leaking for the entire calendar year.

• If multiple leak detection surveys are conducted, assume that the component found to be leaking has been leaking since the previous survey or the beginning of the calendar year.

• For the last leak detection survey in the calendar year, assume that all leaking components continue to leak until the end of the calendar year.”

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Leaker vs Population Factor

• Leaker emission factor applies only to equipment found to be leaking

• Population emission factors apply to the total count of the type of equipment regardless of whether or not it is actually leaking

the voice and choice of public gasthe voice and choice of public gasPopulation Emission Factors -

• Distribution Mains– Unprotected Steel = 12.77 cf/hr/mile– Protected Steel = 0.36 cf/hr/mile– Plastic = 1.15 cf/hr/mile– Cast Iron = 27.67 cf/hr/mile

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• Distribution Service lines– Unprotected Steel = 0.19 cf/hr/service– Protected Steel = 0.02 cf/hr/service– Plastic = 0.001 cf/hr/service– Copper = 0.03 cf/hr/service

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Population Emission Factors

• Below Grade Metering-Regulating station– Inlet Pressure > 300 psig = 1.32 cf/hr/station– Inlet Pressure 100-300 psig = 0.20 cf/hr/station– Inlet Pressure < 100psig = 0.10 cf/hr/station

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Population Emission Factors

• For above grade meter-regulator stations, the population emission factor is the average calculated hourly emission rate per meter/regulator run at TD Transfer stations

• EF = Sum (Es,i/8760/Count) (Eq. W-32)• Es,i = Annual volumetric GHG emissions at standard

condition from all equipment leak sources at all above grade TD transfer stations, and

• Count = Total number of meter/regulator runs at all above grade TD transfer stations.

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Go to Spreadsheet

Questions?Questions?

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