Skip to content

It’s Not Fracking to be Concerned with, It’s a Fugitive Hiding Along the Supply Chain that is A Clear-and- Present Danger!

April 22, 2015

Gas Leak CartoonIn his January 2015 State of the Union address, President Obama emphasized two goals: the critical need to limit greenhouse gas pollution, and support for domestic natural gas and oil production, as well as renewable energy sources. His administration is seeking a 40 percent to 45 percent reduction in methane leaks and emissions of other volatile organic compounds from oil and gas wells and supporting infrastructure.

In support of these goals, the Environmental Protection Agency’s (EPA) announced they intend to regulate methane emissions from the oil and gas sector directly, rather than relying on voluntary programs or regulating associated pollutants. The proposal would be first-ever direct regulation on methane.

This presentation will look at methane emissions – fugitive, venting and flaring –from the oil and natural gas system; its impact, sources, and remediation in the context of the regulatory landscape and economic incentives.

Many view natural gas as a transitional fuel, allowing continued dependence on fossil fuels yet reducing greenhouse gas (GHG) emissions compared to oil or coal over coming decades.

Development of “unconventional” gas employing horizontal drilling and hydraulic fracturing, aka fracing” technologies dispersed in shale is part of this vision, as the potential resource may be large, and in many regions conventional reserves using well-known vertical drilling techniques are becoming depleted.

The Department of Energy predicts that by 2035 total domestic production will grow by 20%, with unconventional gas providing 75% of the total. The greatest growth is predicted for shale gas, increasing from 16% of total production in 2009 to an expected 45% in 2035.

Although natural gas is promoted as a bridge fuel over the coming few decades, in part because of its presumed benefit for global warming compared to other fossil fuels, very little is known about the GHG footprint of natural gas emissions from the oil and gas industry.

While methane is valuable as a fuel, it is also a greenhouse gas at least 21 times, possibly as much as 32 times, more potent than carbon dioxide over a 100-year period, with even greater relative impacts over shorter periods. In late 2010, the U.S. Environmental Protection Agency issued a report concluding that fugitive emissions from the natural gas system from wellhead to burner may be far greater than previously thought.

1 lb. CH4  equals 21to 32  lbs. CO2

1 lb. CH4 equals 21 to 32 lbs. CO2

These fugitive emissions of methane are of particular concern. Methane is the major component of natural gas and a powerful greenhouse gas. As such, small leakages are important. Recent modeling indicates methane has an even greater global warming potential than previously believed, when the indirect effects of methane on atmospheric aerosols are considered.

Emissions are either fugitive, vented or flare related:
• Fugitive emissions are those that “leak” unintentionally from equipment such pumps, valves, flanges, or other equipment – air emissions from locations other than stacks, vents, chimneys, or other fixed locations designed for releasing emissions.
• Vented emissions are releases due to equipment design or operational procedures, such as from pneumatic device bleeds, blowdowns, incomplete combustion, or equipment venting.
• Flaring is a combustion process used in petroleum refineries, chemical plants, and natural gas processing plants as well as at oil or gas production sites having oil wells, gas wells, offshore oil and gas rigs and landfills. Natural gas emissions are due to incomplete combustion.

Despite all the talk about climate change, anthropogenic greenhouse gas emissions and methane’s potent gas global warming effect, it is surprising to discover, that as of today, the U.S. Environmental Protection agency exempts the Oil and Gas industry from direct controls of natural gas emission.

The global methane budget is poorly constrained, with multiple sources and sinks all having large uncertainties suggests fossil fuels may be a far larger source of atmospheric methane than generally considered.

The Natural Gas System
The natural gas system or value chain is a highly integrated system where gas is produced, processed, and delivered to consumers.

Gas industry flow chart

The complexity and extent of the system in the U.S. makes the problem of accurately identifying point sources of emissions and reducing those emissions more difficult. Additionally, each sector has different factors affecting where, when and how much are the CH4 emissions.

The cost of finding and repairing major emitter is one of the primary reasons; the EPA exempted the industry from controlling emissions under the Clean Air Act.

Field Production: In this initial stage of field production, wells are used to withdraw raw gas from underground formations. The oil and gas industry is an aggregate of 21 major production companies with another 6,000 or so, production companies of all sizes.  There are about 2.7 million wells in the United States; of which 900,000 are active and about 1.8 million are abandoned. Of the 900,000 wells, 400,000 produce oil and approximately 500,000 natural gas dispersed within 33 states.

Gathering is the system of pipes that collects gas from the wells for downstream processing.  While some of the needed processing can be accomplished at or near the wellhead, field processing, the complete processing of natural gas takes place at a processing plant, usually located in a natural gas producing region. The extracted natural gas is transported to these processing plants through a network of gathering pipelines, which are small-diameter, low pressure pipes. There exists about 200,000 miles of gathering pipe, typically 8-5/8” or less transporting natural gas at 500 psi. This is in conjunction with over 10,000 gathering stations, and 100,000 gathering compressors.

Processing. Natural gas used by consumers, is much different from the natural gas brought from underground up to the wellhead. Although the processing of natural gas is in many respects less complicated than the processing and refining of petroleum, it is equally as necessary before its use by end users. The natural gas used by consumers is composed almost entirely of methane. However, natural gas found at the wellhead, although still composed primarily of methane, is by no means as pure. Natural gas processing at any one of 580 processing plants in the U.S. consists of separating all of the various impurities, other hydrocarbons and fluids from the natural gas, to produce what is known as ‘pipeline grade natural gas that meets specified tariffs. Pipeline quality natural gas is 95-98 percent methane.

Transmission and Storage. Transmission, involves the delivery of natural gas from the wellhead and processing plant to city gate stations or industrial end users. Transmission occurs through a vast network of high-pressure pipelines. Natural gas storage falls within this sector. Natural gas is typically stored in depleted underground reservoirs, aquifers, and salt caverns.

The transmission sector includes about 320,000 miles of large diameter interstate and intrastate pipelines, between 24 and 48 inches in diameter. The pipes transport pressurized natural gas at 1,000 psi from any one of 1,800 compressor stations. The transportation system also includes about 400 underground storage facilities consisting of depleted underground reservoirs, aquifers, and salt caverns.

Within this network, there are more than 11,000 delivery points, 5,000 receipt points, and 1,400 interconnection points that provide for the transfer of natural gas throughout the United States. Twenty-nine hubs or market centers provide additional interconnections.

Distribution focuses on the delivery of natural gas from the major pipelines to the end users (e.g., residential, commercial and industrial). Distribution pipelines take the high-pressure gas from the transmission system at “city gate” stations, reduce the pressure and distribute the gas through primarily underground mains and service lines to individual end users.

There was over 2 million miles of distribution mains in 2011. The distribution sector is operated by 1,200 companies that serve 66 million residential, 5.3 million commercial, and 191,000 industrial customers as well as 1,700 natural gas-fired electricity power plants, throughout the United States.

The natural gas is periodically compressed to ensure pipeline flow, although local compressor stations are typically smaller than those used for interstate transportation. Because of the smaller volumes of natural gas to be moved, as well as the small-diameter pipe that is used, the pressure required to move natural gas through the distribution network is much lower than that found in the transmission pipelines.

While natural gas traveling through interstate pipelines may be compressed to as much as 1,500 pounds per square inch (psi), natural gas traveling through the distribution network requires as little as 3 psi of pressurization and is as low as ¼ psi at the customer’s meter.

Overall, it is no wonder that such a massive distributed system of as pipes, valves, pumps, compressors, connectors, and flanges is prone to leaks.
There are several tangible and intangible drivers forcing the reduction methane emissions. From a social perspective, there is climate change and public awareness that possibly the scientists were right and the warming effect of anthropogenic greenhouse gas emissions of CO2 and CH4 are having a negative impact on the world’s environment, right before our eyes.

Reducing methane emissions, as we will see, is a powerful way to take action on climate change; and putting the wasted methane to use can support local economies with a source of clean energy that generates revenue, spurs investment, improves safety, and leads to cleaner air. That is why in his Climate Action Plan of 2014, President Obama directed the Administration to develop a comprehensive, interagency strategy to cut methane emissions.

Categorizing the US Greenhouse Gas Inventory by type of Gas.
The critical question is: Given the current extent of U.S. natural gas production—and the fact that production is projected to expand by more than 50 percent in the coming decades—what is the baseline natural gas fugitive emissions and are we doing everything we can to ensure that emissions are as low as is technologically and economically feasible?

U.S. Greenhouse Gas Inventory 2011

U.S. Greenhouse Gas Inventory 2011

This pie chart, U.S. Greenhouse Gas Inventory, illustrates the relative contribution of direct greenhouse gases to total U.S. emissions in 2011, that is the US greenhouse gas inventory. The primary greenhouse gases in the US inventory are CO2 and CH4 contributing approximately 82% percent and 10% to total greenhouse gas emissions, respectively. U.S. EPA Draft Inventory of U.S. Greenhouse Gas Emissions and Sinks: 1990 to 2011.

Defining Atmospheric Methane by Industry
This pie chart, U.S. Methane Emissions by Source, provides a summary of the major contributors of CH4 emissions. The primary sources of atmospheric methane was natural gas systems, enteric fermentation associated with domestic livestock digestion of feedstock (occurring in the intestines), and decomposition of wastes in landfills, see pie chart on the right.

U.S. Methane Emissions by Source

U.S. Methane Emissions by Source

Natural gas systems are the largest anthropogenic source of CH4 emissions in the United States, accounting for approximately one-quarter of total CH4 emissions in 2011.

Enteric fermentation, the second largest anthropogenic source of CH4 emissions in the United States in 2011, enteric fermentation contributed about 23 percent to the total CH4 emissions, an increase of 3.5 percent since 1990. This increase in emissions from 1990 to 2011 in enteric generally follows the increasing trends in cattle populations.

Landfills, the third largest anthropogenic source of CH4 emissions in the United States, accounted for 17.5 percent of total CH4 emissions in 2011.

In 2011, CH4 emissions from coal mining were 23 percent of total CH4 emissions. This amount represents an overall decline of 24.8 percent from 1990 results from the mining of less gassy coal from underground mines and the increased use of CH4 collected from degasification systems.

Manure management methane emissions were about 9% of the total CH4 emissions. Manure management refers to the capture, storage, treatment, and utilization of animal manures.

Petroleum systems and wastewater management methane emission contributed about 5 and 3 percent, respectively, to the inventory of CH4 emissions.

Methane emissions from wastewater management are produced when municipal and industrial wastewater and their residual solid by-product (sludge) are handled under or subject to anaerobic conditions.

Other sources of methane – rice cultivation, abandoned underground coal mines, iron and steel production, field burning of agricultural resides and silicon carbide production  – also play a role to atmospheric methane emissions.

Natural gas system’s contribution of methane to US’s total greenhouse inventory is estimated to be about 2.4 percent; that is, total CH4 emissions of 10% multiplied by 24%, its contribution to the methane component of the greenhouse gas inventory.

EPA Reporting Rules for the O&G Industry
On December 30, 2010, the EPA is promulgated a regulation to require monitoring and reporting of greenhouse gas emissions from petroleum and natural gas systems. The GHG reporting rules are contained in Title 40 CFR part 98 – Mandatory Greenhouse Gas Reporting.

The action does not require control of methane emissions.

GHG reporting is for actual emissions, unlike air permits, which are for Potential To Emit (PTE) emissions. The rule requires a facility that has actual emissions of 25,000 metric tons or more of CO2e per year to submit an annual report of GHG in electronic format to the EPA.
Methane Emissions: Natural Gas System
Identifying the sectors within the natural gas system contributing to methane emissions;

Natual Gas Supply Chain Fugitive Leakage Diagram

Methane leak rates specified in the paper, “Methane Leaks from North American Natural Gas Systems.” Credit: Stanford University/Science

This figure from the U.S. Environmental Protection Agency shows the leakage estimates by major industry segments along the supply chain – from preproduction activities of drilling and hydraulic fracturing, followed by production, processing, transmission, distribution and end use at homes, buildings, factories and modes of transportation,

The EPA estimates the leakage rate, the amount of gas lost per unit of production, throughout the natural gas systems at about 1.5%. Of the 1.5% losses, drilling and fracturing contributed 13% to the total emissions – production another 27% – processing 13%, with remaining 47% coming from the transportation and distribution sectors.

Field Production activities account for 31 percent of CH4 emissions from natural gas systems. Emissions at natural gas well pads come from leaks, pumps, unloading liquids from wells, pneumatic devices, compressors, condensate tanks and dehydrators. Leaks can also come from leaks, pneumatic devices and compressors at gathering stations, which increase the pressure of the gas in the gathering pipeline.

Methane emissions at Oil well pads methane are lower than gas wells and again come from, leaks, pneumatic devices, and storage tanks.

However, flaring of associated gas at oil well pads is an additional source of CH4 emissions and account for the majority of the non-combustion CO2 emissions.

Processing plants account for 15 percent of CH4 emissions from natural gas systems. Fugitive CH4 emissions from compressor venting, including leaky compressor seals, are the primary emission source from this stage. The majority of non-combustion CO2 emissions come from acid gas removal units, which are designed to remove CO2 from natural gas.

CH4 emissions from the transmission and storage sector account for approximately 44 percent of emissions from natural gas systems, while CO2 emissions from transmission and storage account for less than 1 percent of the non-combustion CO2 emissions from natural gas systems. Compressor station facilities, which contain large reciprocating and turbine compressors, are used to move the gas throughout the United States transmission system. Fugitive CH4 emissions from these compressor stations and from metering and regulating stations account for the majority of the emissions from this stage.  Pneumatic devices and engine un-combusted exhaust are also sources of CH4 emissions from transmission facilities.

Natural gas is also injected and stored in underground formations, or liquefied and stored in above ground tanks, during periods of low demand (e.g., summer), and withdrawn, processed, and distributed during periods of high demand (e.g., winter).  Compressors and dehydrators are the primary contributors to emissions from these storage facilities.

Distribution system emissions, which account for approximately 20 percent of CH4 emissions from natural gas systems and less than 1 percent of non-combustion CO2 emissions, result mainly from fugitive emissions from city gate stations and pipelines, where the gas is measured and decompressed before it is put into final sales lines to the consumers.

An increased use of plastic piping, which has lower emissions than other pipe materials, has reduced emissions from this stage. Distribution system CH4 emissions in 2011 were 16 percent lower than 1990 levels.

While not shown, customer meter-sets were found to contribute approximately 5 percent, to annual emissions from equipment leaks. Emission form outdoor residential customer meter sets account for 96 percent of the annual fugitive emissions from customer meters, whereas commercial and industrial meter sets account of only 4 percent.

Point Source of Emissions
The Gas Research Institute (GRI) and the U.S. Environmental sponsored a program to quantify methane emissions form the gas industry, starting at the wellhead and ending immediately downstream of the customer’s meter. The major contributors to emissions from equipment leaks are components associated with compressors, which have unique design and operating characteristics and are subject to vibrational wear. Components represent mechanical joints, seals, and rotating surfaces, with in time tend to wear and develop leaks.  The largest emission point source is the compressor blowdown open-ended lines BD OEL, which allows the compressor to be depressurized for maintenance or when idle.

This bar chart aggregates emissions by component from data presented in the preceding table. By doing this, it is easier to identify the major point sources of emissions.   It is rather obvious that compressor blowdown operations far exceed all other component emissions.

Average Facility Emissions in Transmission Sector

Average Facility Emissions in Transmission Sector

 

CH4 Fugitive Emission Reduction Opportunities
A groundbreaking analysis commissioned Environmental Defense Fund and conducted by ICF International (ICF) shows that the U.S. oil and gas industry can significantly and cost-effectively reduce emissions of methane – using currently available technologies and operating practices.

The report concluded:
• There are real cost-effective solutions available today that can put natural gas on a safer path for communities and for the climate.
• Methane emissions from U.S. oil and gas are projected to increase 4.5% by 2018 as emissions from industry growth – particularly in oil production – outpace reductions from regulations already on the books.
• Industry could cut methane emissions by 40% below projected 2018 levels at an average annual cost of less than one cent on average per thousand cubic feet of produced natural gas by adopting available emissions-control technologies and operating practices. This would require a capital investment of $2.2 billion, which Oil & Gas Journal data shows to be less than 1% of annual industry capital expenditure.
• If the full economic value of recovered natural gas is taken into account, the 40% reduction is achievable while saving the U.S. economy and consumers over $100M per year.
• The most cost-effective methane reduction opportunities would create over $164M net savings for operators.
• Almost 90% of projected 2018 emissions will come from oil production and existing natural gas infrastructure.
• A number of solutions, particularly in the upstream of the oil and gas value chain, will have environmental co-benefits at no extra cost, by reducing emissions that can harm human health, like volatile organic compounds and hazardous air pollutants.

Methane Mitigation Technologies
Several technologies are currently available that can economically reduce fugitive and vented methane emissions. The nine most promising technologies include:
• Implementing Leak Detection and Repair Programs
• Rerouting “Blowdown” Open-Ended Lines
• Replacing Wet Seals with Dry Seals in Centrifugal Compressors
• Installing Vapor Recovery Units on Storage Tank
• Installing Plunger Lift Systems in Gas Wells
• Wet Seal Degassing Recovery System for Centrifugal Compressors
• Converting High‐Bleed Pneumatic Devices to Low‐Bleed
• Reciprocating Compressor Rod Packing Replacement.
• Convert Natural Gas‐Driven Chemical Pumps (Kimray Pumps)

EPA STAR Program
EPA’s Natural Gas STAR Program has been most successful program so far in mitigation emissions in the oil and gas natural gas system. STAR is a flexible, voluntary partnership that encourages oil and natural gas companies—both domestically and abroad—to adopt cost-effective technologies and practices that improve operational efficiency and reduce emissions of methane while benefiting the environment, industry and the government.

Currently, Gas STAR includes 109 domestic oil and gas partner companies from all sectors, representing about 50% of the U.S. natural gas industry and 18 international Partners.

Between 1993 when the program begin through 2012, the Natural Gas STAR Program reported over 1 trillion cubic feet of methane emissions reductions since the program began in 1993 by implementing approximately 150 cost-effective technologies and practices.

This Figure shows Domestic Natural Gas STAR Methane Emissions Reductions from its start in 1993 to 2012. Each year since 1993, Natural Gas STAR partners have reported on the emission reduction activities undertaken to create a permanent record of their voluntary activities.

Natural Gas STAR Program Emission Reductions, Annual and Cumulative

Natural Gas STAR Program Emission Reductions, Annual and Cumulative

In 2012, Natural Gas STAR and Natural Gas STAR U.S. partners reported over 66 billion cubic feet (Bcf) in methane emission reductions by implementing nearly 50 technologies.

These methane emissions reductions had cross-cutting benefits on domestic energy supply, industrial efficiency, revenue generation, and greenhouse gas emissions reductions.

Alone, the 2012 emission reductions are equivalent to:
• The additional revenue of more than $264 million in natural gas sales (assumes an average natural gas price of $4.00 per thousand cubic feet).
• The avoidance of 26.7 million tonnes CO2 equivalent.
• The carbon sequestered annually by 5.7 million acres of pine or fir forests.

Adding to the success reported under the domestic Program, progress was also made in reducing global methane emissions through Natural Gas STAR International. International partners reported 7.6 Bcf in methane emissions reductions for a total of 98 Bcf since the inception of Natural Gas STAR International Program in 2006.

This figure shows the 2012 methane emission reductions breakdown by each sector – Production, which includes Gathering and Processing, and Transmission, and Distribution.

2012 Natural Gas Emission Reductions by Sector

2012 Natural Gas Emission Reductions by Sector

As in past years, the oil and gas production sector reported the largest reductions, accounting for 82 percent or 54 Bcf of the total reductions. The Transmission sector followed at 15% for 10 Bcf of the total methane emissions reductions.

Methane emissions reductions in 2012 occurred though the implementation of nearly 50 technologies and practices

Examples of technologies and practices used to reduce methane emissions included:
• Perform reduced emissions completions
• Use Directed Inspection and Maintenance (DI&M)
• Install flash tank separators on glycol dehydrators
• Use pipeline pumpdown techniques to lower pressure
• Implement a third-party damage prevention programs

These proven technologies and practices reduce methane emissions that would normally escape to the air from wells, storage tanks, and other equipment. These reductions result in significant environmental benefit by reducing methane, a potent greenhouse gas (GHGs), as well as reducing volatile organic compound (VOC) emissions, a precursor to ground-level ozone pollution.

Summary
In summary, EPA could reduce the sector’s methane pollution in half in a just few years by issuing nationwide methane standards that require common sense, low-cost pollution controls for the sector’s top emitting sources:

The methane abatement potentials are conservative estimates based on government inventories. They don’t account for the research indicating that actual emissions could be twice the inventory estimates, or higher. The problem and the upsides of controlling it—are likely much greater.

Regular leak detection and repair programs can reduce methane pollution by an estimated 1,700,000 to 1,800,000 metric tons per annum (MMTA).

Cleaning up older equipment—compressors and gas-driven pneumatic equipment—with proven technologies and practices can reduce methane pollution by an estimated 1,200,000 to 1,350,000 metric tons per annum.

The cost of the recommended standards would be low—less than one percent of the industry’s sales revenue.

The impacts of various drivers on reducing methane emissions from voluntary measures by oil and gas production are already positive. For example, regulatory and social mandate to reduce emissions are driving oil and gas operators to modify traditional operating practices by reducing natural gas venting during oil and gas production.

Technology developments are allowing operators to implement changes, capture, and sell more natural gas.

Advertisements
5 Comments leave one →
  1. Anonymous permalink
    April 22, 2015 3:22 PM

    Thanks Barry – A great overview on this important but often neglected matter. Do keep up.

  2. April 22, 2015 6:49 PM

    Anton,
    Thank you!
    Barry

  3. Rich permalink
    April 23, 2015 4:02 PM

    Very Wise Observation that No One besides you and the ShowTime non-network documentary “Years of Living Dangerously” special addressed on one of their show.

    All this fugitive methane to atmosphere in addition to animal FM, garbage organic FM..

    Thanks for sharing!

    Rich

  4. sidabma permalink
    April 24, 2015 12:01 AM

    Sidel Systems USA Inc. can’t do everything, but the one thing we are capable of doing is removing the Waste Heat Energy and the CO2 out of the combusted natural gas.
    What will be vented is Cool exhaust and over 90% of the CO2 will be TRANSFORMED into useful – saleable products.

    Wasted Energy is Created Energy that has not yet been provided a purpose. Sidel Systems has developed the purposes for these components in combusted natural gas and coal.
    Clean Coal is possible. With our CCU technology combusted coal will emit into the atmosphere less CO2 than combusted natural gas.

    Our technology will TRANSFORM the CO2 into useful – saleable products.

    What is America’s goal in our battle against Climate Change?
    How many Btu’s of heat energy do we Not want to emit into the atmosphere?
    How many Tons of CO2 must Not be allowed to enter the atmosphere?

    There is WATER in combusted fuels. How much of this water do we want on the ground instead of in the atmosphere?

    Where is the biggest need?

  5. Anonymous permalink
    May 15, 2015 5:55 PM

    This article does an excellent job of simply presenting all of the components of the U.S. natural gas system. I also like the fact that it doesn’t just highlight the problem of fugitive emissions, but ends by outlining some common-sense solutions that will significantly reduce the problem allowing this precious resource to continue fueling the manufacturing renaissance that we’ve seen over the past few years.

Leave a Reply

Fill in your details below or click an icon to log in:

WordPress.com Logo

You are commenting using your WordPress.com account. Log Out / Change )

Twitter picture

You are commenting using your Twitter account. Log Out / Change )

Facebook photo

You are commenting using your Facebook account. Log Out / Change )

Google+ photo

You are commenting using your Google+ account. Log Out / Change )

Connecting to %s

%d bloggers like this: