Steve Hamburg: Energy Exchange

This piece originally appeared on our EDF Voices blog. Both science and environmentalism are changing – driven more and more by more collaboration and rapidly improving technology. These developments offer tremendous opportunities, as they can reveal urgent threats much more clearly – as well as the paths to address them. Shifting scientific research in another […]

A new paper published in Science last week is the culmination of an extensive amount of research conducted over the past six years examining methane emissions from the U.S. oil and gas supply chain. The study finds that the U.S. oil and gas industry emits 13 million metric tons of methane per year – 60% […]

We’ve all seen TV detectives dust a scene for fingerprints. In a study in the journal Nature, a team of scientists did something similar, using carbon isotopes to identify the “fingerprints” of methane– one of the world’s most powerful climate pollutants in the atmosphere. The study examined the isotopic signature from two types of methane […]

The United States produces approximately 33 trillion cubic feet of natural gas each year. A majority of this gas is converted to electricity at power plants or used for industrial purposes, but about one third ends up making the journey from the well head, through underground pipelines, and into our homes and businesses. How much […]

A paper today in the journal Science, estimating emissions from the massive methane leak at Aliso Canyon, indicates that nearly 100,000 metric tons of methane escaped into the atmosphere over Southern California – more than previous estimates. The new findings come days after the Environmental Protection Agency released draft results of their updated accounting of […]

A new scientific study published today in the Proceedings of the National Academy of Sciences, coordinated by EDF, reports findings from the most comprehensive examination of regional methane emissions completed to date. Focused on Texas’ Barnett Shale – one of the nation’s major oil-and-gas-producing regions – the study uses a new, more accurate way to […]

Methane emissions from vast oil and gas operations in the densely populated Barnett Shale region of Texas are 50 percent higher than estimates based on the Environmental Protection Agency’s (EPA) greenhouse gas inventory, according to a series of 11 new papers published today in Environmental Science & Technology. The majority of these emissions are from […]

The everyday use of natural gas across the greater Boston area is resulting in much higher emissions of methane than previously thought, according to a study published this month in the Proceedings of the National Academy of Sciences. These emissions represent the waste of a valuable energy resource as well as an important source of […]

Throughout history, maps have played a critical role in shaping our decisions—helping us determine where we are going and how we are going to get there. Now, we’re using them to define a way to address climate change. Environmental Defense Fund and Google Earth Outreach have worked together to launch a series of maps that show methane […]

America is in the midst of two booms: one in sensor technology and another in natural gas. Recent innovations—specifically advancements in drilling and hydraulic fracturing technologies—have dramatically increased the nation’s access to reserves of natural gas. While this influx of new technology has altered the energy industry, the resulting large-scale development has brought with it […]

It has happened again. Another scientific study finds methane emissions from oil and gas production are higher than previously thought, reinforcing the urgent need to reduce emissions of this powerful climate pollutant. The latest study, accepted today to be published in American Geophysical Union’s Journal of Geophysical Research – Atmospheres, measured methane concentrations in the air […]

Nearly every month, for the past six months, a new scientific study has been released that provides new insights in to where methane, a highly potent, climate-destabilizing greenhouse gas, could be reduced across the entire natural gas system – the next six months will be no different. But this week, a new joint Purdue-Cornell study […]

By Steven Hamburg

This commentary originally appeared on the EDF Voices Blog.

Mounting scientific evidence underscores the crucial importance of reducing methane emissions in the U.S. The latest study, published today in the journal Science, reviewed available data from the past 20 years and found that methane emissions from the U.S. natural gas supply chain are almost two times greater than current official estimates – flagging once again that methane emissions are a serious problem. However, the Stanford-led team also concluded that the current levels of methane leakage negates the climate benefit of switching to natural gas under some scenarios and not others, such as moving from coal-powered to natural gas electric generation.

As for what contributes to the higher than expected emissions, the study authors cited differing measurement techniques—including “bottom-up” direct measurement at the source, “top-down” readings from aircraft, and others—as well as the presence of “super-emitters” (a small number of sites or pieces of equipment producing a large share of emissions). Super-emitters are not easily sampled using most bottom-up direct measurement approaches. The team also spotlighted challenges associated with an increasingly ambiguous distinction between emissions from natural gas and oil production, both of which contribute methane to the atmosphere.

Other recent studies

This sobering assessment joins a growing list of recent studies that point to higher than expected levels of methane emissions from the oil and gas industry.

Just a few months ago, a Harvard led team published a paperin the Proceedings of National Academy of Sciences (PNAS)that found total methane emissions from all sources (e.g. livestock, landfills, oil and gas, etc.) were roughly 50 percent higher than U.S. Environmental Protection Agency estimates for the same time period, 2007 -2008.

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This followed on the heels of the September 2013 PNASpaper, in which a University of Texas team looked at emissions from some activities associated with hydraulically fractured wells for the first time. The UT led bottom-up study was the first study released in EDF’s methane research series. Though it found total emissions for the production segment of the natural gas system to be similar to EPA estimates, it also found that emissions from some sources were much higher than EPA estimated – valves, compressors, and pipes located at the well pad, for example, all showed higher than estimated emissions. The study also found that emissions from well completions – at the end of the hydraulic fracturing process – were dramatically lower than EPA estimates where new emission controls were used. This is likely because in 2012, when the measurements were made, drillers were beginning to deploy the reduced emissions completions (REC) equipment required by EPA. RECs will be required for all new natural gas wells beginning in January 2015, but are not required for associated oil-and-gas wells. One clear policy implication was that REC equipment should be required across the board.

In August 2013, yet another study was released, this time by scientists with the National Oceanic and Atmospheric Administration and the University of Colorado at Boulder who are known for their expertise with top-down measurements. Published in Geophysical Research Letters, the paper reported alarmingly high levels of methane emissions from airplane readings gathered over an area of the Uintah Basin, Utah’s most active oil-and-gas region that includes production, gathering systems, processing and transmission stations.

These insights, combined with what we’re learning from the bottom-up studies highlighted in the Science paper, demonstrate that no single measurement method is sufficient to provide all the data required to understand emissions rates and sources. That’s why the diverse scientific teams EDF is working with across our 16 studies are using a wide range of techniques in tandem. (The Stanford study is not a part of EDF’s methane series, though EDF’s senior scientist Robert Harriss is a co-author.)

The Stanford paper is insightful work and we welcome the new perspectives it provides. Their survey of over 20 years of scientific literature makes an important contribution, and raises important issues about all measurement techniques in use. For example, self-selection bias may be a factor in bottom-up direct measurement studies, and top-down techniques have challenges in assigning attribution among sources. None of this takes away from the fact that these studies, despite their methodological differences, clearly indicate that methane emissions pose a serious threat to the climate. And while we work to deepen our understanding of the sources of methane emissions, there’s no question about the need for regulation to reduce these emissions.

Why methane matters

I know some are still not convinced that methane matters. A concern I hear is that reducing methane emissions is a distraction from the important work of reducing emissions of carbon dioxide (CO2). I agree that we need to remain focused on CO2 reductions, but by also reducing harmful emissions of short-lived climate pollutants such as methane, we can slow the rate of warming over the next couple of decades – something that CO2 reductions are unlikely to accomplish alone. And as I said, the threat is real. Over 40 percent of the warming experts expect to see in the next 20 years, as a result of today’s greenhouse gas emissions, will come from short-lived climate pollution that includes methane.

It is absolutely necessary for us to continue pushing as hard as we can to meet our obligation to future generations to leave a cleaner and safer world. But we also need to ensure that the shorter-term impacts of climate change – extreme weather patterns, long droughts and high temperatures seen across the country – are not intensified.

What EDF and a growing number of scientists are saying is that when it comes to emissions reductions, no one should choose between methane and carbon dioxide. It’s not an either/or scenario. Science has shown us that we need to reduce both if we want to protect the climate. We cannot afford to even consider a trade-off between current generations and future generations, which is what this comes down to. We need to protect both – and the only way to do that is to bring together our best ideas for reducing carbon dioxide AND methane emissions.

Reason for hope

There’s reason to hope that if we do this – taking the steps now to create parallel strategies to cut methane emissions from the oil and gas industry (the largest industrial source of U.S. methane emissions) and continue to cut carbon pollution from power plants – it can have a sizable impact. And the good news is that we have affordable technologies to get started. An economic analysis in the International Energy Agency’s 2013 World Energy Outlook 2013 indicates oil and gas companies could reduce methane leaks in production fields by 50 percent at a cost of less than 1 percent of the cost of the well. This is a powerful message about the feasibility of addressing methane emissions, with an enormous upside for the climate.

The community of researchers EDF is working with will be releasing many studies over the coming year. These studies will provide ever more detailed information about sources and magnitudes of methane emissions from which it will be possible to craft ever more effective mitigation strategies. In the meantime, we need to get on with the work of reducing methane emissions and reaping the climate and air quality benefits immediately. We have everything we need to get started. And our future depends on it.

By Steven Hamburg

You may have seen news reports about a new methane emissions study conducted by climate researchers from Harvard and seven other institutions and just published in Proceedings of the National Academy of Sciences (PNAS).  The new paper provides an improved estimate of the total methane budget of the US – in other words, how much methane is being released into the atmosphere each year from all sources, including livestock and oil-and-gas production.

Based on analysis of nearly 5,000 air samples collected in 2007 and 2008 from ten communications towers located around the country, as well as 7,700 samples taken in those years from an aircraft monitoring program, the study finds that total methane emissions due to human activity were roughly 1.5 times greater at that time than previously estimated.  Emissions from livestock were roughly twice as high as previous estimates.  Emissions from oil-and-gas operations in Oklahoma and Texas were 2.7 times higher than estimated.

We are glad to see the methane issue getting the attention it deserves.  While EDF's work to deepen our understanding of current emissions continues, there’s no question about the need for regulation to measure and reduce these emissions.  In August, scientists with the National Oceanic and Atmospheric Administration (NOAA) and the University of Colorado (UC) at Boulder published a long-awaited paper on methane leakage in the journal Geophysical Research Letters that reported an alarmingly high level of methane emissions in the Uintah Basin of Utah — 6.2 to 11.7 percent of total production for an area about 1,000 square miles. 

But there’s some promising news too.  Just last week, the state of Colorado proposed innovative policies that, if adopted, will be the first in the nation to directly regulate methane.  We know more than enough to get started on this issue, as Colorado just did.

The new study is also consistent with the EDF-coordinated University of Texas study published in PNAS earlier in the fall in that both underscore the urgent need for effective methane control rules.  But direct comparisons between the two studies are difficult, since the UT study focused on one part of the natural gas supply chain – production – in 2012, while the new study seeks to encompass all sources of methane emissions based on data from the middle of the previous decade.  So comparing them is like comparing apples to oranges, but they are in no way contradictory or inconsistent.

EDF didn't fund the new PNAS study, but we have funded this team of scientists to use the same techniques in our efforts.  The team is guided by strong science, and that is why we asked them to join us as collaborators.  EDF is acknowledged in this paper for our support.

By Steven Hamburg

Carbon is typically considered enemy number one in the context of climate-altering pollution. There is good reason why. Carbon dioxide (CO2) emitted from power plants is the leading source of U.S. greenhouse (GHG) emissions. Beyond our borders, the historic level of 400 parts per million of GHGs entering into our earth’s atmosphere was passed just five months ago – an indication of the rapid rise in human-produced emissions.

And while reducing carbon pollution is the primary goal of EDF’s climate agenda, so is minimizing methane emissions from natural gas development. That’s because methane, the main ingredient in natural gas, is a powerful GHG that can cause major climate damage in the short term. In fact, a recent analysis by many of the world's top experts on evolving climate science, the Intergovernmental Panel on Climate Change (IPCC), reports methane to be at least 84 times more potent than CO2 over the first two decades. On a 100-year timeframe, methane is at least 28 times more potent. These are noticeable changes in methane’s Global Warming Potential (GWP) from the IPCC's last assessment in 2007, with values raised from 72 to 84 and 25 to 28, roughly a 17 percent increase on a 20-year time horizon and a 12 percent increase on a 100-year basis.

IPCC’s fifth assessment (AR5) also quantitatively discusses two additional indirect effects that further increase, albeit modestly, methane's GWP. First, IPCC considers climate-carbon feedbacks and reports two sets of GWP values: one that accounts for the feedbacks and another that excludes them (they conclude that including this effect is "likely" to give a more accurate estimate of climate impacts from emissions of greenhouse gases like methane or CH4). The 20-year GWP for methane with feedbacks increases from 84 to 86, with the 100-year GWP up from 28 to 34. The explanation for this feedback is diminishing ability of oceans and soils to absorb carbon dioxide as the climate warms. As a result, as methane emissions warm the climate, more CO2 that would have historically been absorbed by the land and ocean remains in the atmosphere, causing additional warming. The second effect now quantified by the IPCC is the production of additional CO2 as CH4 is oxidized in the atmosphere, which adds another point or two to methane's GWP.

Another new development in IPCC’s AR5 is the increased attention devoted to an alternative metric, Global Temperature change Potentials (GTP), in addition to considering GWP based implications. In contrast to the former assessment where GWP was the recommended metric, IPCC does not explicitly make a judgment about whether GTP or GWP is better to use when analyzing methane’s climate impact.  Between the two, the difference in short to medium-term implications of using one metric over the other is limited. Over the longer-term (100 years), the GTP metric suggests that methane emissions today are less important on future climate than are indicated by GWP values. However, the implications of either metric are the same: reducing methane emissions quickly is essential to gain climate benefits over the next ten to 20 years, as well as the critical importance of reducing carbon emissions for their long-term impacts.

As the science is evolving, so is our understanding. EDF scientists re-ran the underlying math behind the widely referenced breakeven points in the 2012 Alvarez et al. paper, published in the Proceedings of National Academy of Sciences that helped us better answer questions about whether natural gas can offer sustained climate benefits. Based on IPCC’s AR5 and the Environmental Protection Agency’s (EPA) 2011 Greenhouse Gas Inventory (released in 2013), the revised understanding of when the amount of total methane emissions affects the climate negatively or positively relative to switching from coal or oil to natural gas under specific technology scenarios is shown in this image.

Under the coal to natural gas fuel-switching scenario, natural gas is indicated to be better for the climate than coal on the day the switch is made if less than 2.7 percent of natural gas produced is emitted before the point of use, versus the former 3.2 percent. Similarly, transitioning a gasoline fleet to run on compressed natural gas (CNG) is estimated to be better for the climate so long as the natural gas emitted is below 1.4 percent, instead of 1.6 percent. Factoring these new inputs into the last fuel-switching scenario, class 8 heavy-duty vehicles operated with a compression-ignition engine burning ultra-low sulfur diesel versus a spark-ignition CNG engine, a net positive for the climate is only achieved if no more than 0.8 percent of gas produced is lost to the atmosphere. To put these values into context, the current well-to-pump natural gas loss rate estimate that is based on methane emissions data from the latest EPA inventory is 1.5 percent of total natural gas produced.

These tipping points greatly depend on the type of technology choices made. For example, in the coal comparison, the threshold would vary if a different assumption was used to compare a new natural gas plant versus an existing coal plant, since the 2.7 percent is applicable only to an efficient combined cycle natural gas plant versus an efficient supercritical pulverized coal plant burning low-gassy coal. There are fewer scenarios to consider in the power sector than in transportation, given the development of new LNG (liquefied natural gas) and CNG engines for commercial trucking. As such, it becomes more difficult to pinpoint a single target where under all technology scenarios natural gas delivers sustained climate benefits. EDF scientists are further analyzing the most viable technologies for fleet conversions and will report their findings in 2014.

Overall, the science continues to reinforce the significant impact of methane, and it is critical that these emissions come down in order to reduce the rate of climate change over the coming decades – and the ecological and social disruptions that come with them. Focusing our attention on methane, along with carbon, makes sense given the reduction opportunities and technologies that exist. Now it is critical to put the data currently being collected by a diverse group of EDF’s academic and industry partners to work in minimizing the amount of methane lost to the atmosphere a reality, and soon.

By Steven Hamburg

Concerns about the methane problem associated with the U.S. natural gas boom are mounting with each study released. This week scientists with the National Oceanic and Atmospheric Administration (NOAA) and the University of Colorado (UC) at Boulder published a new paper on methane leakage in the journal Geophysical Research Letters. It reports an alarmingly high level of methane emissions in the Uintah Basin of Utah — 6.2 to 11.7 percent of total production for an area about 1,000 square miles. Findings are based on readings from airplane flights that measured methane in the air on a single day and estimated the proportion of those emissions that came from the oil and gas infrastructure —production, gathering systems, processing and transmission of the gas out of the region. The authors calculated the uncertainty of their measurements, finding a 68 percent chance the leak rate is between 6.2 and 11.7 percent, and a 95 percent chance it is between 3.5 and 14 percent.

This follows two other regional studies conducted by scientists at the same organizations. One released last May in the Journal of Geophysical Research reported a 17 percent methane leak rate for the Los Angeles Basin, which has received quite a bit of attention although, as I’ll explain below, the figure can be misleading.  The second study, conducted over the Denver-Julesburg Basin in 2008, found 4 percent of the methane produced at an oil and gas field near Denver at that time was escaping into the atmosphere. Taken together, these studies are troubling. They should be regarded as alarm bells ringing in our ears. Action by policymakers and industry is needed now.

Any amount of methane lost from the natural gas supply chain should be eliminated whenever possible. That’s because methane retains heat much more effectively relative to carbon dioxide: Over the first 20 years, an ounce of methane traps in heat 72 times more efficiently. Even small amounts vented or released as “fugitives” – unintentional methane leaked as gas moves from the field to your doorstep – can reduce or eliminate the climate advantage we think we’re getting when we substitute natural gas for coal or oil.

That said, in order to understand how to reduce the leaks we must recognize that each study offers a snapshot of emissions at a specific time, across a specific basin. Different industry sources make up the emissions profile in these areas, including distinct amounts of oil and gas production, and varying components of the natural gas supply chain (production, gathering, processing and local distribution).  By comparison, the latest estimates from the U.S. Environmental Protection Agency suggest that 1.5 percent of total U.S. natural gas production was lost to venting or leakage in 2011. We have a lot of work to do to understand the apparent disparities between different estimates and studies.

Though Environmental Defense Fund was not involved in any of these studies, we can offer some important context based on our own experience doing research on this critical issue.

Methane emissions can occur from natural gas produced both from oil and gas wells. In order to get a clear understanding of the problem, it is necessary to pay careful attention to the details of each study.  In the Los Angeles study, for example, the authors report a 17 percent leakage for the oil and gas industry, but fail to highlight that the vast majority of total hydrocarbon production in the basin is oil. This led some to the mistaken conclusion that 17 percent leakage applies to the natural gas industry as a whole.

Certainly, this finding still indicates more should be done to better control methane emissions associated with oil production in the Los Angeles Basin.  But it also points to a limitation with methane leak rates: Percentages quoted are not comparable between basins. Regional differences matter.

Further, oil and gas production in the Los Angeles Basin study only accounted for 8 percent of the region’s total methane emissions, compared to 48 percent from natural gas distribution and geologic seeps. The Los Angeles study underscores the importance of looking at the total picture when assessing sources and remedies of methane pollution.

The Uintah study is a slightly different story.  In this case, the basin is made up predominantly of natural gas producing wells, but the overflight captured more than just production activities.  Emissions from gathering, processing, and other various ancillary activities taking place in the basin were also captured in the overflight, with no way to attribute the high emissions among these various elements of the natural gas supply chain.

In other words, there is as of yet no data to tell us whether the emissions are coming from production, gathering, processing or other activities.  We know that industry-wide, the production process known as well completions (the process after hydraulic fracturing when a well is cleared of fluids and sands) may contribute about 10 percent of the total methane emissions if operators are not using “green completion” technologies that capture emissions for sales or beneficial reuse. Under recently enacted federal regulations, which EDF fought to adopt, green completions will be required nationally for any new hydraulically fractured natural gas well starting January 2015. There’s no data on whether operators in the Uintah were using green completions at the time of the study, but there is reason to suspect they were not. The Uintah study authors cite a U.S. Government Accountability Office report that notes higher rates of methane flaring and venting at the time of the study than in surrounding production basins.

More investigative work is needed before we can claim to understand what is driving these apparently large emissions. We don’t know everything we need to about the production and distribution practices employed in the Uintah Basin when this research took place, but there is no reason for the public to remain in the dark.  Producers, gathering and processing companies, and pipeline companies in the Uintah Basin must provide citizens with a clear accounting of what they were doing at the time these measurements were made, what they are currently doing and what they will do to end polluting practices and reduce methane pollution.  Likewise, federal and state regulators governing air rules in Utah need to take a hard look at their regulatory and enforcement practices, and provide evidence to assure the public that they are employing necessary procedures to prevent air pollution from the oil and gas infrastructure.  The evidence would suggest they are lagging. It appears there is a lot of work to do in Utah, and companies and regulators alike should not waste a moment in getting after it – including steps to routinely survey emissions in active basins to measure progress over time.

As to what these studies mean for our nation as a whole, one  need is additional data — a comprehensive and consistent look at methane emissions at various locations across the country — in order to properly characterize methane across the U.S. natural gas supply system. That’s why EDF, along with close to 100 academic, research and industry partners, is working on a series of 16 studies to directly measure methane emissions across the supply chain. Together, these sixteen studies will provide the most complete national picture of methane emissions to date.

The first study, led by the University of Texas and involving nine natural gas producers, will be published in the coming weeks. The UT study is not based on emissions from a single location but on measurements from diverse regions with data collected at the actual source. Direct measurements in the UT study focus on methane lost at the well pad and other natural gas production points, and will provide insights into how effectively specific industry practices can contain methane emissions. But it won’t offer a complete picture of methane emissions across all of the natural gas system. We’ll need the entire series of studies, a project that will continue through 2014, before we can draw comprehensive conclusions about the scope of the problem and the full range of options for minimizing methane emissions.

The Uintah and Los Angeles studies tell us that methane emissions appear to be a serious problem in some regions. Additional data will tell us more about where emissions are occurring and what can be done to reduce them.  But we know enough to get started fixing the problem. There is no reason to wait.

By Steven Hamburg

In recent days, news reports and blog posts have highlighted the problem of fugitive methane emissions from natural gas production — leakage of a potent greenhouse gas with the potential to undermine the carbon advantage that natural gas, when combusted, holds over other fossil fuels. These news accounts, based on important studies in the Denver-Julesburg Basin of Colorado and the Uinta Basin of Utah by scientists affiliated with the National Oceanic and Atmospheric Administration (NOAA) and the University of Colorado (UC) at Boulder, have reported troubling leakage rates of 4% and 9% of total production, respectively —higher than the current Environment Protection Agency (EPA) leakage estimate of 2.3%.

While the Colorado and Utah studies offer valuable snapshots of a specific place on a specific day, neither is a systematic measurement across geographies and extended time periods  and that is what’s necessary to accurately scope the dimensions of the fugitive methane problem. For this reason, conclusions should not be drawn about total leakage based on these preliminary, localized reports. Drawing conclusions from such results would be like trying to draw an elephant after touching two small sections of the animal’s skin: the picture is unlikely to be accurate. In the coming months, ongoing work by the NOAA/UC team, as well as by Environmental Defense Fund (EDF) and other academic and industry partners, will provide a far more systematic view that will greatly increase our understanding of the fugitive methane issue, though additional studies will still be needed to fully resolve the picture. What follows is a briefing on the fugitive methane issue, including the range of measurements currently underway and the need for rigorous data collection along the entire natural gas supply chain.

Why methane leakage matters. Natural gas, which is mostly methane, burns with fewer carbon dioxide emissions than other fossil fuels. However, when uncombusted methane leaks into the atmosphere from wells, pipelines and storage facilities, it acts as a powerful greenhouse gas with enormous implications for global climate change due to its short-term potency: Over a 20-year time frame, each pound of methane is 72 times more powerful at increasing the retention of heat in the atmosphere than a pound of carbon dioxide. Based on EPA’s projections, if we could drastically reduce global emissions of short-term climate forcers such as methane and fluorinated gases over the next 20 years, we could slow the increase in net radiative forcing (heating of the atmosphere) by one third or more.

Fugitive methane emissions from natural gas production, transportation and distribution are the single largest U.S. source of short-term climate forcing gases. The EPA estimates that 2.3% of total natural gas production is lost to leakage, but this estimate, based on early 1990’s data, is sorely in need of updating. The industry claims a leakage rate of about 1.6%. Cornell University professor Robert Howarth has estimated that total fugitive emissions of 3.6 to 7.9% over the lifetime of a well.

To determine the true parameters of the problem, EDF is working with diverse academic partners including the University of Texas at Austin, the NOAA/UC scientists and dozens of industry partners on direct measurements of fugitive emissions from the U.S. natural gas supply chain. The initiative is comprised of a series of more than ten studies that will analyze emissions from the production, gathering, processing, long-distance transmission and local distribution of natural gas, and will gather data on the use of natural gas in the transportation sector. In addition to analyzing industry data, the participants are collecting field measurements at facilities across the country. The researchers leading these studies expect to submit the first of these studies for publication in February 2013, with the others to be submitted over the course of the year.

The systemic leakage rate will determine whether or not natural gas provides a net climate benefit, with implications for assessing the relative environmental benefits of fuel switching from coal or diesel to natural gas.

Note: EDF’s model disaggregates the leak rate of 2.8% as follows: 2.0% is leakage from well to city gate (this applies to power plants); 2.3% is leakage from well-to-end user (applies to homes and industrial users); the additional 0.5% accounts for leakage from natural gas vehicle refueling and use.

As this chart illustrates, lowering the methane leakage and venting rate to 1% of total production would double the climate benefit derived from coal-to-natural gas fuel switching over the next 20 years — producing as much climate benefit in that time as closing one-third of the nation’s coal plants. (This assumes that 1% is the amount of natural gas produced at well sites lost to the atmosphere, in comparison to a baseline of 2.8%, and that the retired coal-fired generation is replaced with equal parts high efficiency natural gas fired generation and zero-emissions electric generation, such as renewables.)

Preliminary studies. Recently, a series of studies has emerged, each providing a snapshot of leakage from a specific region and a specific segment of the natural gas system at a specific point in time:

• 2010; Fort-Worth, TX: Analysis of reported routine emissions from over 250 well sites with no compressor engines in Barnett Shale gas well sites in the City of Fort Worth revealed a highly-skewed distribution of emissions, with 10% of well sites accounting for nearly 70% of total emissions. Natural gas leak rates calculated based on operator-reported, daily gas production data at these well sites ranged from 0% to 5%, with 6 sites out of 203 showing leak rates of 2.6% or greater due to routine emissions alone.
• February 2012; Denver-Julesburg, CO: Tower study by NOAA/University of Colorado at Boulder scientists suggested that up to 4% of the methane produced at a field near Denver was escaping into the atmosphere.
• December 2012: At an American Geophysical Union meeting in San Francisco, the NOAA/University of Colorado at Boulder team described the unpublished results of a study in the Uinta Basin, Utah, suggesting even higher rates of methane leakage, 9% of total production.
• Forthcoming studies include: March 2013 (est.) reporting by University of Texas at Austin (in collaboration with nine corporate partners and EDF) of a study about emissions from gas production; subsequent 2013/early 2014 studies will address gathering, processing, long-distance transmission and local distribution.

Some of these studies have revealed or are likely to reveal relatively high levels of fugitive methane emissions, while others are likely to reveal lower levels. None of them, taken alone or in tandem, can yet provide an accurate picture of system-wide leakage. As a news story in the journal Nature concluded, “Whether the high leakage rates claimed in Colorado and Utah are typical across the U.S natural-gas industry remains unclear. The NOAA data represent a 'small snapshot' of a much larger picture that the broader scientific community is now assembling.”

Great care should be taken to avoid drawing conclusions based on the partial data these studies provide. This will be a particular challenge given that advocates for natural gas production are likely to call attention to the low-leakage results, while opponents of natural gas production are likely to call attention to the high-leakage results, with each side claiming that the latest study “proves” its argument. Neither claim will be reliably accurate.

In other words, anyone who wants to get this important story right will need to be patient and wait for the more comprehensive results to come in later this year. Until then, no accurate conclusion can be drawn about the full scope of this critical issue. Please proceed with caution.

By Steven Hamburg

Concerns around the impacts of methane emissions have reemerged in headlines, with the release of a methane leakage study about Boston. Published in the journal of Environmental Pollution a couple weeks ago, researchers from Boston University and Duke University measured atmospheric methane concentrations leaking from natural gas pipelines in Boston many of which are over a hundred years old. Another report issued last week by researchers at the Massachusetts Institute of Technology (published in Environmental Research Letters) looked at the impact of shale gas production on greenhouse gas emissions.

When talking about harmful greenhouse gases, carbon dioxide (CO2) usually gets most of the attention. Yet methane, the main ingredient in natural gas, is a short-lived greenhouse gas many times more potent than CO2 – or around 72 times more potent over a 20-year time frame. Stakes are high for the scientific community to fully understand the implications of methane leakage rates. These reports help elevate the issue that methane leakage matters to the climate and air quality, but this is only part of the story.

Methane is potentially leaking from the entire natural gas supply chain — from wells, pipelines and storage facilities — and no one knows precisely how much is leaking and where the leaks are stemming from. Some reports estimate the total methane leakage rate occurring during natural gas production, transmission and distribution to range anywhere from 1 to 7.9 percent. At the same time, the data that the Environmental Protection Agency (EPA) and everyone else rely on were collected 20 or more years ago.

A challenge for understanding the distribution of methane concentration data in Boston is that no one knows how to interpret the data yet. Maps of methane concentrations in the urban environment can be spurious. They may look scary, but are they? This and many other tough scientific questions still need to be answered, we are very early in the process of understanding how much methane is leaking and from where. The scientific community at large, including EDF and the authors of the Boston study, are committed to collecting the data necessary to addressing these concerns and to understanding the true climate impact of methane emissions.

EDF is working with leading academic researchers and industry leaders to conduct scientifically rigorous measurements of quantitative emissions across the natural gas supply chain from well to the end user. We are developing the methodologies where necessary to move past a ‘he said, she said’ conversation to one focused on data characterizing leak rates. The critical next step for us in using the increasingly robust data gathered from new innovative technologies is to precipitate a clear enough understanding of where the leaks are in the supply chain to catalyze a constructive conversation about what new policies and industry practices will be required to minimize methane leakage.

The first EDF fugitive methane report, focused on field measurements made at natural gas production sites, will be completed early next year under the leadership of the University of Texas Austin. EDF and our partners are using a diverse array of measurement techniques to characterize leak rates. We are also working to make basin-wide measurements within areas of natural gas production. Over the course of 2013 and early 2014, studies of emissions at other key components in the supply chain, including the local distribution system, will be completed and the data and conclusions released to the public.

EDF is actively campaigning to ensure that fugitive methane emissions from the natural gas industry are less than 1 percent of production in order to ensure that the climate benefits of natural gas are maximized. We see development of innovative, cost effective and accurate methane detection technologies and procedures as a necessary part of minimizing leak rates. Our view is that minimizing methane leakage is an important enough issue that we need to take the time to establish a scientific understanding of the underlying issues and by doing so defining effective well-targeted actions.

By Steven Hamburg

While natural gas burns cleaner than other fossil fuels when combusted, methane leakage from the production, transportation, and use of natural gas has the potential to undermine some or all of those benefits, depending on the leakage rate.  Methane is the main ingredient in natural gas and a greenhouse gas (GHG) pollutant many times more potent than carbon dioxide (CO2), the principal contributor to man-made climate change.

In other words, leaks during the production, distribution, and use of natural gas could undermine, and possibly even overwhelm, the greenhouse gas advantage combusted natural gas has over coal and spell major trouble for the climate.

Up to this point, direct measurement data on methane leakage rates has been limited and subject to wide interpretation and debate.  Some studies have estimated the leak rate to be as high as 7.9%, while others have estimated the leak rate to be as low as 1% for some aspects of the drilling process.  Methane leakage matters, and has clear implications on whether natural gas can be seen as a lower carbon energy source.  To help overcome some of the debate, EDF is working with leading academic researchers and industry leaders from across the natural gas sector to take direct measurements of leak rates to help better define the natural gas leak rate across the natural gas supply chain in the United States.

In partnership with the EDF and nine leading natural gas producers, today the University of Texas Austin (UT) announced the first part of this study, focused on emissions from natural gas production.  The study will help provide a clearer picture of methane leakage rates occurring at natural gas drilling sites around the country.  It is particularly relevant because drilling and completion processes have evolved rapidly in recent years – thanks to breakthroughs in horizontal drilling and hydraulic fracturing – and the knowledge about the methane leaked during this shift has not.

The main objective of this study on production emissions is to obtain scientifically rigorous data from multiple gas producing basins. The study will focus on quantifying emissions from well completions, gas well liquid unloading and well workovers, in addition to other more routine well-site fugitive emissions, the areas of the production process with the greatest leak rate uncertainties

The study is unique in that it brings multiple, key stakeholders to the table to make measurements of emissions at the well pad that will be shared when completed. If natural gas is to become an accepted part of an energy independence strategy, while supporting a clean energy future, it is critical to work together to quantify, and where ever possible lower, the existing methane leakage rate. Such an approach could yield enormous added environmental and health benefits from existing and future natural gas infrastructure.

A research team led by UT, including engineering and environmental testing firms URS and Aerodyne Research, is conducting the extensive field study. Project partners include EDF, Anadarko Petroleum Corporation, BG Group plc, Chevron Inc., Encana Oil & Gas (USA) Inc., Pioneer Natural Resources Company, Shell, Southwestern Energy, Talisman Energy, USA, and XTO Energy, an ExxonMobil subsidiary.

For more information on ways to get sustained benefits from natural gas, EDF published a paper earlier this year titled, “Greater focus needed on methane leakage from natural gas infrastructure.”  Find more at edf.org/methaneleakage.