Mayors’ Council on Pipeline Safety 2015 Conference

May 14, 2015

Lesley FleischmanClean Air Task Force

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Benefits of reducing methane leaksfrom the distribution sector

• Safety– Fixing leaky pipelines can help stop gas leaks before

they create an explosive safety hazard. • Waste – Gas distribution companies leak over $400

million dollars worth of gas in the U.S. in 2013.• Climate– Pound for pound, methane is more than 80 times

worse than carbon dioxide in the coming two decades when warming may begin to change key natural systems.

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Source: EPA, US Greenhouse Gas Inventory

17%

42%

13%

28%

U.S. Methane Emissions by Sector, 2013Total = 423 Bcf

Natural Gas Distribution

Oil and Natural Gas Production

Natural Gas Processing

Natural Gas Transmission and Storage

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45%

43%9%0.3%

3%

Distribution Sector Methane Emissions, 2013Total: 73 bcf

Underground Leaks

Aboveground Meter and Regulator Stations

Customer Meters

Routine Maintenance

Upsets

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Emissions Factors in the EPA’s InventoryPipeline

Type Material Emission Factor Unit

Mains

Cast Iron 238.7

mcf/mile-yearUnprotected Steel 110.19Protected Steel 3.07Plastic 9.91

Services

Unprotected Steel 1.7

mcf/service-yearProtected Steel 0.18Plastic 0.01Copper 0.25

• Based on a study from 1996• “Average” emissions factors

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2 recent studies (with different methodologies)

• McKain et al. Methane Emissions from Natural Gas Infrastructure and Use in the Urban Region of Boston, Massachusetts– Top-Down: Atmospheric measurements and modeling

of Boston area.– Finds methane emissions 2-3x larger than predicted by

existing inventory methodologies and industry reports.• Lamb et al. Direct Measurements Show Decreasing

Methane Emissions from Natural Gas Local Distribution Systems in the United States– Bottom-Up: Measurement of leaks from 13 urban

distribution systems.– Emissions estimate is 36% to 70% less than the 2011

EPA inventory.– Evidence of super-emitters.

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Super-emitters

• Strong evidence suggests that the vast majority of emissions come from a small number of sources

• These large, unusual sources are referred to as “super-emitters”

• These may underrepresented in the component-by-component analysis that makes up the inventory.

• Finding and fixing these super-emitting sources is critical, and comprehensive leak detection and repair (LDAR) programs are essential.

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Infrared (IR) Camera Technology• Methane absorbs infrared

radiation at certain wavelengths on the electromagnetic spectrum.

• IR Cameras can be calibrated to “see” those wavelengths.

• Infrared cameras are now being deployed throughout the oil and gas industry.

• Allow inspectors to detect leaks in real time—rapidly inspecting all components at a facility.

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Leak Detection and Repair (LDAR) Programs (for aboveground leaks)

• LDAR programs require regular surveying of facilities using infrared cameras or other instruments.

• The cost of inspecting facilities is low and, once leaks are found, the cost of repairing the leaks is largely (often entirely) paid for by the value of gas conserved by fixing the leaks.

• Our 2014 report Quantifying Cost-effectiveness of Systematic Leak Detection and Repair Programs Using Infrared Cameras analyzed the costs of LDAR programs at well pads and compressor stations

• LDAR at large aboveground distribution facilities should be similarly cost effective.

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LDAR at Aboveground M&R stations

• In our recent report, Waste Not, we called for quarterly surveys at large aboveground city-gate stations (meters and regulators).

• We estimate this will reduce emissions by 60%.• Saving over 18 bcf per year.

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Underground Leaks:Classification

• Safety classification– Class 1: repaired immediately due to safety concerns.– Class 2: may create a future hazard, scheduled repair.– Class 3: no present or future hazard, monitored.

• Climate/Waste perspective– All leaks important from a climate/waste perspective.– Safety classification is not correlated with emissions magnitude.– Class 2 or class 3 leaks can have high emissions rates, but they may be

further away from infrastructure and population so not an imminent security risk.

– Class 2 and Class 3 can go on longer, so total emissions from these leaks can be high.

– Class 1 leaks are repaired immediately, leak for a shorter length of time, so total methane emitted may be lower.

www.catf.uslfleischman@catf.us

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