Methane Challenge Background - Best Management Practices (BMP) Commitment Option
The Best Management Practices (BMP) Commitment is intended to spur near-term, widespread implementation of methane mitigation activities across the oil and natural gas value chain to address methane emissions from key emitting sources. By committing to address an emission source, a partner commits to implement a BMP on all such sources in their operations. Progress towards a commitment is generally indicated by the percent of sources to which the partner has implemented a BMP as part of the Methane Challenge. Commitments for a few sources are instead based on achieving a target rate (of equipment replacement or methane emission reductions).
This page presents information about the emission sources currently included in the BMP Commitment option:
- Pneumatic controllers
- Fixed roof, atmospheric pressure hydrocarbon liquid storage tanks
- Reciprocating compressors - rod packing vent
- Centrifugal compressors - venting
- Transmission pipeline blowdowns between compressor stations
- Mains – cast iron and unprotected steel
- Services – cast iron and unprotected steel
- Distribution pipeline blowdowns
- Excavation damages
More details can be found in the BMP Commitment Option Technical Document.
Pneumatic Controllers
Applicable Segments:Production, Gathering and Boosting, Transmission and Storage
About This Source: Natural gas pneumatic controllers are automated instruments actuated by pressurized natural gas used for maintaining a process condition such as liquid level, pressure, delta-pressure and temperature. Under the Methane Challenge, this source focuses on continuous high-bleed controllers (i.e., those with a natural gas bleed rate greater than 6 standard cubic feet (scf) per hour). Under Methane Challenge, this source does not cover operational situations in which pneumatic controllers with a bleed rate greater than 6 scf per hour are required based on functional needs, including but not limited to response time, safety and positive actuation.
Available Mitigation Options:
- Utilize natural gas-actuated pneumatic controllers with a continuous bleed rate less than or equal to 6 scf of gas per hour, or
- Utilize zero emitting controllers (e.g. instrument air, solar, electric, or mechanical controllers), or
- Remove natural gas pneumatics controllers from service with no replacement
What This Commitment Entails: A partner commits to implement one (or more) of the above available mitigation options on all pneumatic controllers included in its commitment, by its designated commitment achievement date.
Fixed Roof, Atmospheric Pressure Hydrocarbon Liquid Storage Tanks
Applicable Segments: Production, Gathering and Boosting
About This Source: Atmospheric pressure fixed roof storage tanks receive hydrocarbon produced liquids from onshore petroleum and natural gas production and gathering and boosting facilities.
Available Mitigation Options:
- Route gas to a capture system (e.g., a vapor recovery unit or VRU) for beneficial use to achieve at least a 95% reduction in methane emissions, or
- Route gas to a flare or control device to achieve at least a 95% reduction in methane emissions.
What This Commitment Entails: Partners commit to implement the specified mitigation options for all sources included in their commitment by their designated commitment achievement date.
Reciprocating Compressors - Rod Packing Vent
Applicable Segments: Gathering and Boosting, Processing, Transmission and Storage
About This Source: A reciprocating compressor is a piece of equipment that increases the pressure of a process natural gas by positive displacement, employing linear movement of a shaft driving a piston in a cylinder. Reciprocating compressor rod packing is a series of flexible rings in machined metal cups that fit around the reciprocating compressor piston rod to create a seal limiting the amount of compressed natural gas that escapes to the atmosphere. Rod packing emissions typically occur around the rings from slight movement of the rings in the cups as the rod moves, but can also occur through the “nose gasket” around the packing case, between the packing cups, and between the rings and shaft. As the rings wear, or if the fit between the rod packing rings and rod is too loose, more compressed natural gas can escape.
Available Mitigation Options:
- Replace the reciprocating compressor rod packing every 26,000 hours of operation, or
- Replace the reciprocating compressor rod packing prior to every 36 months, or
- Route rod packing vent to a capture system for beneficial use to achieve at least a 95% reduction in methane emissions, or
- Route rod packing vent to flare or control device to achieve at least a 95% reduction in methane emissions.
What This Commitment Entails: A partner commits to implement one (or more) of the above available mitigation options on all reciprocating compressor rod packing vents included in its commitment, by its designated commitment achievement date.
Centrifugal Compressors - Venting
Applicable Segments: Gathering and Boosting, Processing, Transmission and Storage
About This Source: Centrifugal compressors are any equipment that increases the pressure of a process natural gas by centrifugal action, employing rotating movement of the driven shaft. In wet seal centrifugal compressors, high-pressure oil is used as a barrier against escaping gas in centrifugal compressor shafts. Very little gas escapes through the oil barrier, but under high pressure, considerably more gas is absorbed by the oil. The seal oil is purged of the absorbed gas (using heaters, flash tanks, and degassing techniques) and recirculated; the centrifugal compressor wet seal degassing vent releases emissions when the high-pressure oil barriers for centrifugal compressors are depressurized to release absorbed natural gas. Under the Methane Challenge, this source is focused on centrifugal compressors with wet seals.
Available Mitigation Options:
- Route wet seal degassing to a capture system for beneficial use to achieve at least a 95% reduction in methane emissions, or
- Route wet seal degassing to flare or control device to achieve at least a 95% reduction in methane emissions, or
- Convert wet seals to dry seals or use centrifugal compressors with dry seals.
What This Commitment Entails: A partner commits to implement one (or more) of the above available mitigation options on all centrifugal compressors with wet seals included in its commitment, by its designated commitment achievement date.
Transmission Pipeline Blowdowns Between Compressor Stations
Applicable Segments: Transmission and Storage
About This Source: Blowdowns are the release of gas from a pipeline or section of pipeline that causes a reduction in system pressure or a complete depressurization.
Available Mitigation Options:
- Route gas to a compressor or capture system for beneficial use, or
- Route gas to a flare, or
- Route gas to a low-pressure system by taking advantage of existing piping connections between high- and low-pressure systems, temporarily resetting or bypassing pressure regulators to reduce system pressure prior to maintenance, or installing temporary connections between high and low-pressure systems, or
- Utilize hot tapping, a procedure that makes a new pipeline connection while the pipeline remains in service, flowing natural gas under pressure, to avoid the need to blow down gas.
What This Commitment Entails: Partners commit to maximize blowdown gas recovery and/or emission reductions through utilization of one or more of these mitigation options to reduce methane emissions from non-emergency blowdowns by at least 50% from total potential emissions each year (partners may choose to commit to a higher rate). A partner commits to achieve, and maintain, its specified annual emission reduction rate by its designated commitment achievement date.
Mains – Cast Iron and Unprotected Steel
Applicable Segments: Distribution
About This Source: Distribution mains are natural gas distribution pipelines that serve as a common source of supply for more than one service line. In the Methane Challenge, this source covers cast iron and unprotected steel mains (i.e., steel mains without cathodic protection).
Available Mitigation Options:
- Replace cast iron mains with plastic or cathodically protected steel and replace or cathodically protect unprotected steel mains, or
- Rehabilitate cast iron and unprotected steel pipes with plastic pipe inserts, also referred to as slip-lining or u-liners, or cured-in-place liners:
- Slip-lining is a technique that involves the insertion of a plastic pipe into an existing pipe. The new pipe is pushed or pulled into the host pipe. U-liners are high-density polyethylene (HDPE) plastic piping and are manufactured in a “U” shape with diameter sizing specific to the host pipe in need of repair. The liner is pulled through the host pipe and then reformed to a circular shape after insertion using steam. This process is carried out without the need to trench and results in a structurally sound HDPE plastic pipe fitted tightly within the pipe needing repair. PHMSA provides guidance related to inserting plastic pipe into a metal pipe.
- Cured-in place liners are pipe liners comprised of flexible tubing, jackets, elastomer skin, and adhesive systems. These liners are installed into an existing metallic natural gas pipe in need of rehabilitation. Cured-in place liners provide resistance to gas permeation and provide resistance against damage caused by ground movement, internal corrosion, leaking joints, pinholes, and chemical attacks.
What This Commitment Entails: Partners commit to replace or rehabilitate cast iron and unprotected steel mains at the following minimum annual rates (based on a partner’s total inventory of cast iron and unprotected steel mains) per the mitigation options listed above; partners may choose to commit to higher rates than those designated. A partner commits to achieve, and maintain, its specified annual replacement rate by its designated commitment achievement date.
| Tier | Inventory of Cast Iron and Unprotected Steel Mains |
% Minimum Annual Replacement/Repair |
|---|---|---|
| Tier 1 | <500 miles | 6.50% |
| Tier 2 | 500-1,000 miles | 5% |
| Tier 3 | 1,001 – 1,500 miles | 3% |
| Tier 4 | 1,501 miles – 3000 miles | 2% |
| Tier 5 | >3000 miles | 1.5% |
Services – Cast Iron and Unprotected Steel
Applicable Segments: Distribution
About This Source: A service line is a distribution line that transports gas from a common source of supply to (1) a customer meter or the connection to a customer's piping, whichever is farther downstream, or (2) the connection to a customer's piping if there is no customer meter. (A customer meter is the meter that measures the transfer of gas from an operator to a consumer.) Under the Methane Challenge, this source covers cast iron and unprotected steel services.
Available Mitigation Options:
- Replace unprotected steel and cast iron services with copper, plastic, or protected steel that meet the manufacturing requirements and qualifications provided in 49 CFR Part 192, Subpart B , or
- Rehabilitate cast iron and unprotected steel services with plastic pipe inserts or liners.
What This Commitment Entails: At a minimum, partners commit to replace or rehabilitate cast iron and unprotected steel services when the main is replaced or rehabilitated. Due to the linkage with mains, this source is not eligible for a stand-alone commitment.
Distribution Pipeline Blowdowns
Applicable Segments: Distribution
About This Source: Blowdowns are the release of gas from a pipeline or section of pipeline that causes a reduction in system pressure or a complete depressurization.
Available Mitigation Options:
- Route gas to a compressor or capture system for beneficial use, or
- Route gas to a flare, or
- Route gas to a low-pressure system by taking advantage of existing piping connections between high- and low-pressure systems, temporarily resetting or bypassing pressure regulators to reduce system pressure prior to maintenance, or installing temporary connections between high and low-pressure systems, or
- Utilize hot tapping, a procedure that makes a new pipeline connection while the pipeline remains in service, flowing natural gas under pressure, to avoid the need to blow down gas, or
- Use stopoff/stopple equipment and fittings to reduce the length of pipe and the associated volume of gas being blown down.
What This Commitment Entails: Partners commit to maximize blowdown gas recovery and/or emission reductions through utilization of one or more of these mitigation options to reduce methane emissions from non-emergency blowdowns of pipelines operating greater than 60 psi by at least 50% from total potential emissions each year (partners may choose to commit to a higher rate). A partner commits to achieve, and maintain, its specified annual emission reduction rate by its designated commitment achievement date.
Excavation Damages
Applicable Segments: Distribution
About This Source: Excavation damages may include damage to the external coating of a pipe, or dents, scrapes, cuts, or punctures directly into the pipeline itself. Excavation damage often occurs when required One-Call notifications are not made prior to beginning excavation, digging, or plowing activities, or when calls are made but pipe is still damaged. When the location of underground facilities is not properly determined, the excavator may inadvertently – and sometimes unknowingly – damage the pipeline and its protective coating. Under the Methane Challenge, this source covers both distribution mains and services.
Available Mitigation Options:
- Conduct incident analyses (e.g. by identifying whether excavation, locating, or One-Call practices were not sufficient) to inform process improvements and reduce excavation damages, or
- Undertake targeted programs to reduce excavation damages and/or shorten time to shut-in when damages do occur, including patrolling systems when construction activity is higher, excavator education programs (811, call before you dig), identifying and implementing steps to minimize repeat offenders, and stand-by efforts.
What This Commitment Entails: Partners commit to annually report all data elements by their designated commitment achievement date.