A look at recently released data on methane emissions

[vc_row animation=””][vc_column width=”1/1″][vc_column_text]In the past week there have been several reports and articles released discussing methane emissions (or leaks) from natural gas systems.  With the current interest surrounding this topic, we wanted to bring you up to speed on the latest information.
[/vc_column_text][/vc_column][/vc_row][vc_row animation=””][vc_column width=”1/1″][vc_custom_heading text=”Addressing the “Methane Leaks from North American Natural Gas Systems” paper” font_container=”tag:h4|font_size:28px|text_align:left|line_height:30px” google_fonts=”font_family:PT%20Sans%3Aregular%2Citalic%2C700%2C700italic|font_style:400%20regular%3A400%3Anormal”][/vc_column][/vc_row][vc_row animation=””][vc_column width=”1/2″]
This recently published paper ran in Science Magazine and claimed that there are higher-than-expected methane emissions from natural gas systems –such as pipelines – around North America. One of the findings also stated that there is no benefit to switching diesel vehicles to run on natural gas.
[/vc_column][vc_column width=”1/2″][vc_single_image css_animation=”” image=”6066″ border_color=”” img_link_large=”” link=”https://secureservercdn.net/” img_link_target=”_self” img_size=”medium”][/vc_column][/vc_row][vc_row animation=””][vc_column width=”1/1″][vc_column_text]But as America’s Natural Gas Alliance (ANGA) lays out in this recent blog, this finding was not based on the data collected but rather from a secondary source which uses an “uncharacteristically low estimate of engine efficiency.”
[/vc_column_text][/vc_column][/vc_row][vc_row animation=””][vc_column width=”1/1″][vc_column_text]So basically, instead of going onto locations and directly measuring emission rates from engines burning natural gas, the authors relied on data that only estimated what emissions would be – and did so at a rate far below of what engines in the field are capable of.
[/vc_column_text][/vc_column][/vc_row][vc_row animation=””][vc_column width=”1/1″][vc_column_text]ANGA goes on to further explain:

The paper’s authors outline a number of causes for uncertainty, and so we outline them here:

  • When determining the emissions from the natural gas production process, activity data is important. Adam Brandt, the paper’s lead author, concedes this point and notes that data should improve with increased reporting requirements by the EPA.  The EPA has published data for 2011 and 2012 showing a drop in methane emissions.  While a modest drop, it occurred despite increased natural gas production.

  • Brandt also identifies clear challenges associated with estimating natural gas sector emissions by using an atmospheric approach (“top-down”).  The most significant of these being how observed concentrations of methane are attributed to potential sources.  Does the methane come from fossil sources rather than naturally occurring ones? The authors point out that studies can differentiate liquid petroleum and natural gas sources from coal, but are quick to admit that attributing methane emissions to the natural gas system is “more challenging.”

  • Brandt uses EPA’s Greenhouse Gas Index as a comparative baseline to illustrate how it under-reports methane emissions compared to measurement-based studies.  Estimating methane emissions is a complex and difficult task, and it should be noted that the EPA changes its Inventory every year. The magnitude of these changes can be significant.

In the blog’s conclusion, ANGA states that more information is required to accurately identify the sources of methane emissions to help limit them during natural gas development.
[/vc_column_text][/vc_column][/vc_row][vc_row animation=””][vc_column width=”1/1″][vc_custom_heading text=”EPA’s Greenhouse Gas Inventory” font_container=”tag:h4|font_size:28px|text_align:left|line_height:30px” google_fonts=”font_family:PT%20Sans%3Aregular%2Citalic%2C700%2C700italic|font_style:400%20regular%3A400%3Anormal”][/vc_column][/vc_row][vc_row animation=””][vc_column width=”1/1″][vc_column_text]
In direct opposition to the findings above, the EPA released the latest Greenhouse Gas Inventory which highlights the decrease in methane emissions from natural gas systems.
[/vc_column_text][/vc_column][/vc_row][vc_row animation=””][vc_column width=”1/1″][vc_column_text]Energy InDepth highlighted the findings:

The downward trend that EPA identifies is arresting.  In last year’s Greenhouse Gas Inventory, EPA found that methane emissions from natural gas systems had fallen 10.2 percent since 1990, and emissions from field production had fallen 38 percent since 2006.  Those emission rates were already well below the threshold for natural gas to retain its clear environmental benefits.  In its latest report, EPA finds that methane emissions fell 16.9 percent since 1990, with field production emissions falling more than 40 percent since 2006.
[/vc_column_text][/vc_column][/vc_row][vc_row animation=””][vc_column width=”1/1″][vc_single_image css_animation=”” image=”6067″ border_color=”” img_link_large=”” link=”https://secureservercdn.net/” img_link_target=”_self” img_size=”medium”][/vc_column][/vc_row][vc_row animation=””][vc_column width=”1/1″][vc_column_text]And in an interesting move, the EPA no longer considers natural gas systems as the largest source for methane emissions – it has been surpassed by enteric fermentation. [Enteric fermentation involves cows, for those who are curious]
[/vc_column_text][/vc_column][/vc_row][vc_row animation=””][vc_column width=”1/1″][vc_column_text]The EPA’s report also talked about more than methane emissions.
[/vc_column_text][/vc_column][/vc_row][vc_row animation=””][vc_column width=”1/1″][vc_column_text]From EID’s blog:

But the decline in methane emissions isn’t the only good news from the report.  There has also been a sustained decrease in CO2 emissions, thanks largely to our increased use of natural gas. From the report:
[/vc_column_text][/vc_column][/vc_row][vc_row animation=””][vc_column width=”1/1″][vc_column_text]“In 2012, total U.S. greenhouse gas emissions were 6,501.5 Tg or million metric tons CO2 Eq. Total U.S. emissions have increased by 4.4 percent from 1990 to 2012, and emissions decreased from 2011 to 2012 by 3.3 percent (225.0 6 Tg CO2 Eq.). The decrease from 2011 to 2012 was due to a decrease in the carbon intensity of fuels consumed to generate electricity […] with increased natural gas consumption.” (2-1)

[/vc_column_text][/vc_column][/vc_row][vc_row animation=””][vc_column width=”1/1″][vc_custom_heading text=”Summarizing the methane emission findings” font_container=”tag:h4|font_size:28px|text_align:left|line_height:30px” google_fonts=”font_family:PT%20Sans%3Aregular%2Citalic%2C700%2C700italic|font_style:400%20regular%3A400%3Anormal”][/vc_column][/vc_row][vc_row animation=””][vc_column width=”1/1″][vc_column_text]
What to take away regarding emissions:

  • The report in Scientific America is flawed for suggesting that switching vehicles from diesel to natural gas has no environmental benefits due to using hypothetical numbers rather than collecting data in the field.
  • The EPA reports that the methane emission rates from natural gas systems have declined significantly despite the increased production and infrastructure in the U.S.
  • There is a continuation of a reduction of CO2 levels in the U.S. led by the movement to switch power plants from burning coal to natural gas


Brittany Ramos

Brittany was born and raised in Pittsburgh, Pennsylvania and attended Pennsylvania State University where she earned degrees in Public Relations and Psychology. She recently earned her Masters in Sociology from Sam Houston State University. Brittany works in the External Affairs for Cabot where she manages communications and outreach projects to community members, elected officials, media and online supporters.

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