Fracking = Worse Than Coal

I have to take issue with Cecil Adams’ latest article regarding fracking. In it, he says that fracking and natural gas use are bad, but not as bad as other options like coal. This is flatly untrue. According to a recent Cornell study, up to 8% of the natural gas released by fracking escapes unburnt into the atmosphere, and since natural gas as a greenhouse gas is much more potent than CO2, the resulting emissions make natural gas extraction three times worse for the environment than coal. This isn’t to say we should be burning coal instead, but that we should reject false solutions that lock us in to a fossil fuel future. With Vermont Gas Systems trying to ram a gas pipeline extension down the throats of the Vermont public as I write, it’s important that we keep scrupulously to the facts on this subject.

Do you have a link to the Cornell study?

Not that there isn’t an environmental impact from fracking, but I’d suggest you look at the numbers again.

More to the point, I’d suggest looking at the volume of coal burned (and resulting CO2 emitted) compared to the volume of natural gas released by fracking. It’s not even a close thing. So, yes, by absolute quantity, rather than by relative “badness”, coal is still much, much worse.

If we significantly reduced the use of coal and significantly ramped up fracking, we would, of course, have to take another look.

According to the Environmental Defense Fund, fracking losses are <1% using the latest technology. DOI 10.1073/pnas.1304880110

That really only applies to the larger companies, and doesn’t mean that the many mom-and-pop drillers aren’t screwing things up.

I haven’t had a chance to talk with anyone at EDF since the study came out.

Is that per unit of energy harnessed?

Recently, I read (I think it was Scientific American, but since it gave no reference, it hardly matters) that fracking can be done without environment damage. The discussion was limited to release of methane and poisoning of water. The question is, would it be done that way? The temptation to cut corners would be irresistible and the anti-regulatory meme rampant in the US would probably prevent the kind of close regulation that would be necessary.

Undiscussed was the possibility of triggering earthquakes.

NG becomes worse than coal at only a few percent leakage. Relative “badness”, i.e. radiative forcing, is what’s important here. “Volume” and “absolute quantity” are irrelevant; I’m not sure why you would even bring them up.

It’s a little complicated in that CH4 has a much shorter half life than CO2.


Here’s the column in question. I’ll note that Cecil mentions coal precisely once, and that his broader point is that fossil fuel use — shale gas, coal, tar sands — will have to continue for the foreseeable future if we want to maintain our population and standard of living. I don’t doubt that Cecil would agree with you that both coal and shale gas could be made cleaner and more efficient.

Well, as an example, if we have one well worldwide that is fracked but still burn the same quantity of coal as today, there’s not much of a discussion to be had.

Clearly, we’re fracking more than that. But to blithely state that fracking is overall worse than coal based on per unit volume estimates when we’re burning a ton more coal than extracting natural gas from fracked wells is bordering on misleading.

At any rate, it’s a 2011 study found here. And the results are disputed (even by other colleagues at Cornell) as the data used was of low quality.

Lots of Cornell studies out there. Maybe the OP mean this one? DOI: 10.1029/2012GC004032

Oh wait, no, that says exactly the opposite.

Except that’s how it works; we’re replacing coal with NG. EIA data show that coal use in the US peaked in 2007 (we use ~7% less now.)
Now, overall energy consumption has decreased as well, but only by about half that.

And of course the OP was presumably just talking about greenhouse forcing. If we bring in Hg, particulates, and other emissions, coal has even more problems.

But we sure do have a lot of it!

Fracking actually has very little to do with it in a strict sense, and it annoys me people so often confuse this issue.

In ages past people would drill for oil and gas, often times you’d find both from the same drilling effort or you’d find predominantly gas but not much oil. “Conventional” natural gas (in terms of “conventionally drilled”) is found primarily in gas reservoirs that are created over millions of years as natural gas is produced in some organic-rich formation and then migrates into permeable reservoir rock where it is then trapped by an overlying layer of impermeable rock.

This helpful wikipedia diagram shows some different types of gas. You’ll note what I just described most closely resembles “conventional non-associated gas” and “conventional associated gas.” The broad strip of gray represents impermeable rock that has trapped the gas under the ground. Drilling straight down into these reservoirs punctures that impermeable rock, releasing the natural gas up through the hole you had just drilled and ideally it is then captured and becomes part of the natural gas supply system (where it may be put into storage, transported far away on a pipeline, transported by truck etc etc.)

Note the difference between associated/non-associated conventional gas is whether or not the gas is associated with a petroleum deposit. In that diagram if you drilled down into the underground source of oil you’d have a functioning oil well that would also produce natural gas. Much early natural gas production was incidental to oil production and would be saved off for its own uses–but many times in the past and even sometimes today natural gas was seen as so much less valuable than oil that it would just be flared off as a waste/unwanted byproduct of the oil drilling.

So in that diagram you should also see a broad dark/black strip deeper down, under the first layer of sandstone. That represents a layer of shale that is rich in natural gas. Natural gas has, over millions of years, sort of been trapped/absorbed into the shale. Unlike a traditional natural gas reservoir, just drilling into a shale formation doesn’t do a lot for you, you’d get some slow gas migrating up but nothing like in a traditional well. Instead, shale must be fractured in order for shale gas to be economically extracted. For many years, naturally occurring fractures were found and gas was profitably extracted from those. In more recent years, the technique of hydraulic fracturing was developed. A process where water is forced into shale deposits under high pressure to forcibly fracture the shale, which then releases the natural gas stored in the shale formation.

Commonly, because of the layout of shale deposits it makes sense to combine this with “horizontal drilling” in the shale layer–and thus you have the two components key to the modern shale gas boom, horizontal drilling and hydraulic fracturing (fracking.)

So what must be understood is fracking is just a process for fracturing shale. Fracking in and of itself cannot be “worse than coal” because fracking is not an energy source, it isn’t burned for energy, it’s a process not a thing. That leaves us with a few more “appropriate” questions we can ask:

  1. Is shale gas worse for the environment than coal. The majority opinion appears to be no. The Cornell study you mention is well known, but so are many peer reviewed assessments of it that have found it flawed. The EPA and the IPCC both have a more favorable view of natural gas in general than the Cornell study along with several other major universities refuting different aspects of the study (the wikipedia article on shale gas contains many links to the articles that refute the Cornell study.)

  2. Is shale gas any different than conventional natural gas? The answer to this is “often times yes.” There is no standard composition of natural gas, every well is slightly different. Where it’s important enough to matter, natural gas transportation/distribution companies actually install gas chromatographs on their pipe to measure the composition of their gas. A given Mcf (1,000 cubic feet) is commonly said to contain 1 dekatherm of energy. This is rough “envelope” number based on historical averages. The amount of energy in a given Mcf of gas is basically based on the composition of that gas. In reality an Mcf could have 0.95 Dth or 1.05 Dth or etc. This article gives some more detail about variation in the composition of gas, specific to shale gas.

But in general, shale gas is said to contain more methane per Mcf on average than conventional gas. Methane is a greenhouse gas, a shale gas leak will introduce more methane into the atmosphere than a conventional gas leak (on average.)

  1. Is burning shale gas worse than coal or conventional gas? I don’'t believe there is much argument it is much better than burning coal. Is it better than burning conventional natural gas? My understanding is one Mcf burned of shale gas (on average) will produce more greenhouse emissions than a comparable Mcf of natural gas, but it is exactly proportional to the greater energy produced by the Mcf of shale gas. So while shale gas may be worse per Mcf, I think per Dth (which is what really matters), they aren’t meaningfully different. [I admit to going off of supposition on this point.]

  2. Is natural gas worse than coal for the environment, in total? More important than the burn question is the total production/use of gas versus the total production/use of coal. It’s absolutely correct that if gas, which is much cleaner burning, produced a huge amount of greenhouse emissions versus coal in its production/transportation that natural gas could be worse for the environment than coal.

The first part of the answer is to point out that whether or not natural gas is extracted by conventional drilling or fracking probably isn’t a significant part of the answer to this question. Other than the fact shale gas on average is slightly more rich than regular natural gas (and thus has more methane), from a pollution perspective drilling for natural gas in conventional versus shale plays is not all that relevant to the global warming debate. There is a whole other debate about water usage and affect on local water tables, potential to cause local earthquakes etc that I will not get into here, but those issues do not effect the climate change picture (just like the fact that coal mining and coal plants cause large increases in health risks to local communities isn’t part of its climate change problem but yet another reason coal is very bad.)

The real danger then from natural gas is leakage. Leakage meaning gas that leaks out at the well, uncaptured, or gas that leaks out of the pipeline etc. Leakage directly releases methane into the atmosphere. The thrust of the Cornell study is this leakage releases so much methane that it makes natural gas a bigger climate change risk than coal. Professor Ingraffea noted an industry average leak rate of 5% in an Op-Ed that he released for the NY Times and bases much of his argument that natural gas production is worse in terms of climate change than coal on that number.

However multiple rebuttals have basically said that:

  1. In practice the leakage rate is actually much lower. The EPA’s most recent Greenhouse Gas Inventory suggests a methane leakage rate of 1.4%, lowered from 2.3%.

  2. As Richard A. Muller (a physics professor at UC-Berkeley) and Raymond Pierrehumbert (climate scientist at University of Chicago) point out, because natural gas produciton/use generates far less carbon even a 10% leakage rate would be worth trading from coal to natural gas. Their argument is based on the fact that the effects of methane are understood to be 100% reversible, that methane is more potent but leaves the atmosphere much quicker than carbon, in roughly 20 years any impact of a specific methane leak released into the atmosphere is completely reversed. Carbon on the other hand stays in the atmosphere essentially forever in human terms. For this reason even if there is twice as much leakage as Dr. Ingraffea of Cornell suggested in his op-ed, it might still make sense to switch from coal to natural gas.

So my ultimate answer is that utilizing natural gas instead of coal, while there are serious concerns, is ultimately much better for the climate picture. I base this solely on the fact a large number of scientists say this, I have no preconceptions on the subject being a layman. A large number of these same scientists have specifically refuted Dr. Ingraffea’s study, which suggests it has not well withstood the peer review process.

There are important considerations with natural gas. Just like there are many very bad things coal production and burning do aside from any impact on climate change, natural gas has non-climate related impacts that must be considered. The issue of earthquakes needs to be studied. The issue of all those trucks/drilling equipment ripping up the landscape must be considered. The massive use of water (a scarce resource) must be considered. The fact that there is little Federal regulation of what chemicals go into water used in fracking (it’s a state-by-state patchwork of regulations now) must be considered. The impact on drinking water must be considered. There is also a problem with lack of information. The EPA and other bodies exercise what I would consider to be “too little” oversight of the natural gas industry so it puts a level of unreliability into any statistic we come up with about what sort of chemicals the industry uses, how often they have leaks/spills etc–and that is something it would be nice to see addressed.

This is incorrect. CH4 has a ~12 year lifetime, which means there’s still lots of it left after 20 years. Its 100-year GWP (time-integrated radiative forcing) is still >30x that of CO2. That drops below 8x around 500 years.

If you’re comparing fracking to conventional natural gas production, you also have to ask which process results in more leaks. Based on the stories of people lighting their kitchen faucets, I’d have to guess that fracking is leakier, but I don’t know the numbers.

And comparing anything to coal, one must consider that coal has environmental impacts beyond its CO[sub]2[/sub] and other pollutants. Much coal nowadays is mined through mountaintop removal, for instance, which means a massive destruction of habitat.

That isn’t what Dr. Pierrehumbert says, in fact he specifically says he believes people abuse GWP and it misrepresents the actual effects of CH4:

The relevant papers:

Link Solomon S, Pierrehumbert RT, Matthews DL, Daniel JS (2011) Atmospheric Composition Irreversible Climate Change and Mitigation Policy. WCRP OSC Climate Research in Service to Society (24–28 October 2011. Denver, United States

Link Cathles, L. (2012), Assessing the greenhouse impact of natural gas, Geochem. Geophys. Geosyst., doi:10.1029/2012GC004032, in press.

[The second article is not freely available online that I could find.

and I don’t even play one on TV.

But I’ve requested a moderator to move this to the appropriate forum: Comments on Cecil’s Columns and Staff Reports

In keeping with the practices of that forum, here’s a link to the article in question.

Ok. Carry on.

That’s a good point, but I’m not sure there is a lot of evidence that the fracking process in and of itself produces more leaks. Instead I think fracking and the resulting shale gas boom has resulted in substantially more drilling, which means more total leaks, which means more anecdotal stories about contaminated drinking water. On the drinking water issue, a large amount of the public concern is that the water pumped into the shale deposits can migrate from those deposits into drinking water aquifers. It is my understand this is not supported by what actually happens geologically and is considered (last I read up on that aspect of it) to have never definitively been shown to happen and probably could not due to the large distance between shale deposits and typical underground aquifers.

Instead (and I think as you probably understand based on your post), it seems most drinking water contamination relates to spills of drilling chemicals and gas leaks closer to the wellhead, so intrinsically fracking and conventional drilling both would contaminate drinking water through the same mechanism.

I do think the business realities of fracking could definitely lead to more leaks, but I’m not sure there’s a lot of evidence the process of fracking itself inherently leads to more leaks. The shale gas boom has created a huge industry for drilling companies large and small, and an extreme push to drill as fast as possible. With many States only performing cursory regulation of these operations and the Federal regulations still being relatively toothless I think it creates a perfect storm of heightened drilling activity and a rush to get things fast that in general would also correspond to more accidents/screwups.

It should though be noted that gas companies involved in exploration/drilling do aim for 1% or less leakage for financial reasons. Leakage is less revenue, so there is at least a rare circumstance in play here where the financial motivation strongly incentivizes the best environmental practices. Unfortunately of course there is a difference between many of the drilling crews (often smaller companies) that take contracts from the big gas companies. The drilling crews are often employed either by companies or are smaller time contractors and their prime motivation is to finish a job as quickly as possible because they get paid by the job. The companies that want to see as low a leakage as possible are usually one rung removed from the drilling and thus probably can’t easily guarantee leakage remains as low as they’d like (other than vertical integration or being really choosy with who they have drill their wells.)

Yeah, I was disappointed to see Cecil essentially taking that claim at face value in his column. Saying “check out YouTube” to find factual information is also rarely a good idea.

Moderator Action

Moving thread from General Questions to Comments on Cecil’s Columns/Staff Reports.

Link to Cecil’s article:

Actually, I don’t understand that, or at least didn’t. My questions were honest, not rhetorical: I don’t actually know which is leakier, or if there’s a significant difference, but a flaming water faucet is certainly something one notices. You may well be right that that happens with all gas production, and it’s only been noticed now due to the increased volume.

And concerns about financials might decrease leaks in some cases, but it wouldn’t be a guarantee, depending on how the extraction company values the long term vs. the short: If method A produces more usable (non-leaked) gas per time than method B, but also leads to a greater proportion of leaked gas, the company might still choose A even though it means less total gas extracted in the long run.