Breaking: Natural Gas venting – a major Global Warming Contributor
There are two sources of Methane Gas from human actions to the atmosphere (which are discussed here), the first is from pipe leakage and the second from shale gas development (mainly from venting).
Fueling Global Warming, gas leaks on city streets, which adds about $40 a year to the average Bay State residential gas bill
The perils and price of leaking gas are the subject of a paper that Phillips, Crosson, and Ackley presented at a conference last spring sponsored by the National Oceanic and Atmospheric Administration. Their research suggests that 7 percent to 15 percent of manmade methane (the main component of natural gas) in the atmosphere comes from these urban emissions.
Then there’s the money. The eight billion cubic feet of gas vented in Massachusetts in 2005 (that’s leaks plus gas unaccounted for because of other factors) was worth $41 million, and that annual leak of gas and dollars continues. Gas customers pay a monthly maintenance charge already, in addition to being charged for the gas that leaks away, says Ackley, who for years worked to detect leaks for National Grid and other utilities. He estimates that leaks could add $40 a year to the average Bay State residential gas bill. BU Today
Now, Professor Robert Howarth from Cornell university released a study about Marcellus Natural Gas Development and Global Warming april 2011 and a follow up, Yesterday 19. January 2012 (read below).
Marcellus Natural Gas Development and Global Warming (April 2011)
Abstract: We evaluate the greenhouse gas footprint of natural gas obtained by high-volume hydraulic fracturing from shale formations, focusing on methane emissions.
Natural gas is composed largely of methane, and 3.6% to 7.9% of the methane from shale-gas production escapes to the atmosphere in venting and leaks over the life-time of a well. These methane emissions are at least 30% more than and perhaps more than twice as great as those from conventional gas. The higher emissions from shale gas occur at the time wells are hydraulically fractured—as methane escapes from flow-back return fluids—and during drill out following the fracturing. Methane is a powerful greenhouse gas, with a global warming potential that is far greater than that of carbon dioxide, particularly over the time horizon of the first few decades following emission. Methane contributes substantially to the greenhouse gas footprint of shale gas on shorter time scales, dominating it on a 20-year time horizon. The footprint for shale gas is greater than that for conventional gas or oil when viewed on any time horizon, but particularly so over 20 years. Compared to coal, the footprint of shale gas is at least 20% greater and perhaps more than twice as great on the 20-year horizon and is comparable when compared over 100 years. Source Methane and the greenhouse-gas footprint of natural gas from shale formations
Watch a presentation of above paper:
Yesterday, Howarth released a follow up, after more evaluation and study.
Report: Natural Gas From Shale Not Suitable as “Bridge Fuel,” May Worsen Climate Change
“We believe the preponderance of evidence indicates shale gas has a larger greenhouse gas footprint than conventional gas, considered over any time scale. The greenhouse gas footprint of shale gas also exceeds that of oil or coal when considered at decadal time scales, no matter how the gas is used. We stand by the conclusion of our 2011 research: ‘The large [greenhouse gas] footprint of shale gas undercuts the logic of its use as a bridging fuel over coming decades, if the goal is to reduce global warming.” – Howarth
Professor Robert Howarth and Renee Santoro, researchers in the Department of Ecology & Evolutionary Biology, Cornell University, and Anthony Ingraffea, a professor in the School of Civil and Environmental Engineering at Cornell. Podcast January 19, 2012
“Shale Gas creates 40-60% more methane to the atmosphere from the natural gas industry, than conventional gas.” – Professor R. Howarth
The new study
Abstract: In April 2011, we published the first comprehensive analysis of greenhouse gas (GHG) emissions from shale gas obtained by hydraulic fracturing, with a focus on methane emissions. Our analysis was challenged by Cathles et al. (2012). Here, we respond to those criticisms. We stand by our approach and findings. The latest EPA estimate for methane emissions from shale gas falls within the range of our estimates but not those of Cathles et al, which are substantially lower. Cathles et al. believe the focus should be just on electricity generation, and the global warming potential of methane should be considered only on a 100-year time scale. Our analysis covered both electricity (30% of US usage) and heat generation (the largest usage), and we evaluated both 20- and 100-year integrated time frames for methane. Both time frames are important, but the decadal scale is critical, given the urgent need to avoid climate-system tipping points.
Using all available information and the latest climate science, we conclude that for most uses, the GHG footprint of shale gas is greater than that of other fossil fuels on time scales of up to 100 years. When used to generate electricity, the shale-gas footprint is still significantly greater than that of coal at decadal time scales but is less at the century scale. We reiterate our conclusion from our April 2011 paper that shale gas is not a suitable bridge fuel for the 21st Century. Venting and Leaking of Methane from Shale Gas Development: Response to Cathles et al.
TIME’s reports today
Fracked: The Debate Over Shale Gas Deepens
Is shale gas good for us or not? Most of that argument has been over the potential risks that hydrofracking for shale gas might pose to water supplies—risks that were highlighted again this week when the Environmental Protection Agency (EPA) came to Dimock, PA, to test groundwater in the area. You might know Dimock from the anti-fracking film Gasland—a group of residents have claimed for years that fracking poisoned their water supply, and federal involvement indicates there may be more at stake.
But while water has been the focus of the fracking wars, there’s another debate going on over a hidden aspect of shale gas: its contribution to global warming. Conventional natural gas is by far the cleanest of the fossil fuels—not just in terms of toxic pollutants like ash or sulfur dioxide, but in terms of carbon as well, with a greenhouse gas footprint perhaps half that of coal. But a group of scientists at Cornell University, led by the ecologist Robert Howarth, challenged that consensus in a paper published last year claiming that shale gas might actually be worse for the climate than coal. Their conclusions were heavily criticized by the gas industry as well as some independent experts, and earlier this month another set of Cornell scientists—led by the geologist Lawrence Cathles—published a paper arguing that Howarth’s numbers were wrong, and that shale gas was indeed much less carbon-intensive than coal. And that paper in turn prompted another article by Howarth and his colleagues yesterday make the case that, no, they were right all along.
So what does this all mean—other than the fact that the Cornell faculty club may be getting a little testy these days? Is shale gas good for the climate or bad?
The truth is we can’t be entriely sure. That’s because the one fact that’s most important to nailing down the full greenhouse gas footprint of shale gas—the amount of methane that is spilled into the air accidentally during the production and transportation of gas—isn’t well known. And it isn’t well known in part because the oil and gas industry is famously tight with its data—there have been similar problems trying to find out the ingredients in fracking fluid—which leaves researchers to create models out of bad data. And that leaves a lot of room for interpretation.
In Howarth’s study—and in the follow-up released yesterday—he estimated that as much as 8% of methane from shale-gas production escapes into the atmosphere, where it’s a far more powerful greenhouse gas than carbon. Technically, methane—which is really just another word for natural gas—has about 23 times the global warming potential of carbon dioxide, though it doesn’t stay in the atmosphere as long. As a result, he concluded that gas from fracking could have a greenhouse gas footprint twice as great as coal over a 20-year time frame, and perhaps equal to coal over a century-long frame.
Cathles’s paper earlier this month, though, made the case that Howarth had overestimated the methane leaks from shale gas wells by as much as tenfold, and concluded that natural gas—from fracking or not—remained a bridge to a cleaner future:
In the short term, our energy needs should be satisfied mainly by those fuels having the fewest inherent environmental disadvantages,” Cathles and his co-authors concluded. “Those preferred fuels include natural gas.
Howarth, for his part, obviously disagrees:
We believe the preponderance of evidence indicates shale gas has a larger greenhouse gas footprint than conventional gas, considered over any time scale. The greenhouse gas footprint of shale gas also exceeds that of oil or coal when considered at decadal time scales, no matter how the gas is used. We stand by the conclusion of our 2011 research: ‘The large [greenhouse gas] footprint of shale gas undercuts the logic of its use as a bridging fuel over coming decades, if the goal is to reduce global warming.
Who’s right? Critics I respect, like Michael Levi of the Council on Foreign Relations, have cast a lot of doubt on Howarth’s original conclusions. And even if the climate benefits of shale gas are much less than advertised, it produces far less traditional pollution than coal—which makes a difference on public health. But the reality is that we need more information about potential methane leakages in gas production and transport—and we need stronger regulations to ensure that fugitive gas doesn’t make it into the atmosphere. Still, don’t expect the war of words—and scientific papers—over shale gas to end any time soon. TIME’s
Deliberatlly misleading the public
“From a CO 2 emissions standpoint, [shale gas] is 60 percent cleaner than coal” – William Colton, VP of Exxon Mobil for corporate planning, NY Times, Oct. 10, 2010
“60 Minutes” on CBS Television on November 14, 2010 made essentially same statement