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Hydraulic fracturing well head.

Fracking

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by Chris Woodford. Last updated: December 3, 2017.

Gold, iron, oil, coal—should we count ourselves lucky to live on a planet packed with rocky riches? Or unlucky—because we've arrived at the party too late, when oil wells are starting to sound like drinks cartons being drained to the dregs? Among all the resources on Earth's endangered list, oil is the one that causes most concern; sometimes called liquid gold, it's the fuel that powers a billion car engines, thousands of power plants, and millions of home heating systems. Economists and geologists have been predicting the end of cheap oil for about a half century; environmentalists have been flagging the dangers of our overdependence on fossil fuels (oil, gas, and coal) for just as long.

What will we do when the oil runs out? Ideally, swap our gas guzzlers for electric cars and replace our dirty coal power plants with squeaky-clean solar and wind. But all that takes years or decades—so what will we do in the meantime? What if we could squeeze just a little bit more fuel from the planet to keep us going? That's the basic idea behind fracking (hydraulic fracturing), a method of blasting high-pressure jets of water into underground gas and oil deposits to flush out more of Earth's tricky-to-reach resources. Oil and gas companies see fracking as an economic lifeline that will keep them in profit a few decades longer. Environmentalists, however, see it as an environmental disaster that will tip the planet over the edge into catastrophic climate change. With the debate over fracking so bad tempered and polarized, how can we know who's right? Whose arguments do we believe? Can we really afford to frack? Can we really afford not to? How do we balance economic arguments against environmental ones? Should we even try? Let's take a closer look and find out!

Photo: A typical well head installed above the Fayetteville shale of Arkansas. These are the pipes through which the fracking fluid flows down into the ground. Photo by Bill Cunningham courtesy of US Geological Survey.

What is fracking?

Fracking's the informal name for hydraulic fracturing—a self-explanatory term, when you think about it a little bit. In science and engineering, hydraulics means using pressurized water to power machines like diggers and cranes. If a jet of water can help a bulldozer shift rocks, maybe it can do other useful things too. If you shoot it down a gas or oil well, the sheer pressure will crack apart (fracture) the rocks inside, releasing trapped oil and gas that can flow to the surface and be captured. Some of these tricky deposits are buried in tough-to-reach places that we can't easily drill down to. That's why fracking is very often used with another relatively modern oil exploration technique called horizontal drilling (also called directional drilling). Unlike in a traditional oil well, where the drill string (the spinning pipe that carries the drill bit deep underground) sinks more or less straight down, horizontal drilling allows the entire string to bend through sharp angles to access oil and gas fields located off to the side. (Another advantage is that one drilling rig on the surface can be used to drill a number of different horizontal wells in different directions.) Working hand-in-hand, fracking and horizontal drilling have made it possible to exploit three relatively inaccessible types of geological deposit from which oil and gas are otherwise hard to recover: shale gas (natural gas locked in shale formations), coalbed methane (CBM) deposits (the methane gas that naturally occurs in coalfields—once considered a dangerous nuisance, but now seen as a useful resource), and tight sands (sandstone and limestone rocks in which natural gas is tightly trapped).

How does fracking work?

Labeled diagram showing the key steps in the fracking process.

Fracking starts with a well (1) bored several thousand meters vertically through aquifers (groundwater rocks, 2), and then horizontally into an oil or gas deposit (3). Once the hole's been drilled, it's cased with a continuous steel pipe sunk down (and then sideways) the entire length of the hole, which is cemented into place to make a kind of giant "drinking straw" through which oil and gas can be extracted (4). A special perforation gun is lowered down through the pipe and small explosive charges make holes at various points so the fracking fluid can be pumped in at high pressure, from trucks on the surface (5). This creates many small cracks in the deposit through which the trapped oil or gas can escape (6).

Although the name "hydraulic" fracturing suggests only water is used, fracking fluid actually contains three main ingredients:

Perforations in a fracking pipe.

Photo: Fracking fluid is blasted into the ground through holes perforated in the base of the pipe sunk into the well. Photo by Bill Cunningham courtesy of US Geological Survey.

Once the rock is fractured, pumping stops, so the pressure is released. The gas or oil trapped underground flows back to the surface with some of the water and chemicals from the fracking fluid and other deposits flushed up from underground, making up what is technically called flowback. Fracking can also release what's called produced water ("released water" might be a better name for it), which is naturally occurring water trapped in something like a shale formation. Produced water also carries trapped minerals, naturally radioactive materials, and so on. Since flowback and produced water both potentially contain toxic chemicals and flushed out salts and other harmful substances, they're classed as contaminated wastewater. Some of this toxic mix might be reused on other fracking operations, while the rest must be treated and stored since it's too contaminated to be released into rivers or seas.

The benefits of fracking

Nodding donkey oil pump

Photo: Not all our fuel can be pumped out of the ground as easily as with this "nodding donkey." Fracking can help extend our oil and gas reserves, bringing tremendous economic benefits—but at what cost? Picture courtesy of US Department of Energy.

At first sight, fracking is a classic example of development that pits economic arguments (benefits) against environmental ones (costs). That makes the debate very emotive and difficult to settle: how do you argue that apples (economic benefits) are better than pears (environmental benefits) when they're totally different things? As we'll see shortly, that's a huge oversimplification because some of the environmental arguments against fracking are actually economic ones, while some of the economic benefits of fracking are also (according to the oil and gas companies) environmental benefits too. But let's try to keep things simple by looking at the economic side of things first, before moving onto the environmental issues afterward.

The biggest argument in favor of fracking is that it helps the oil and gas industry to recover more fossil fuels at a time when the world's supply appears to be peaking. In the United States alone, fracking has produced tens of billions of dollars worth of shale gas in the last few years: over half of all natural gas produced in the United States in 2015 came from shale deposits.[1] After a long period of decline, by 2013, the United States was the world's biggest natural gas producer, and currently generates around 21 percent of the entire planet's gas supply (just ahead of Russia's 17.8 percent).[2] That's helped to knock down the price of US natural gas by about a quarter to a third in the last few years.[3] The United States has also seen a massive increase in domestic oil production, which has bounced back from a 30-year decline to the kind of levels that haven't been seen since 1973, again largely thanks to fracking of shale.[4] Expanding businesses create jobs—and it's no coincidence that the booming US oil and gas extraction industry has created a million new jobs since 2007.[5]

Pie chart of world natural gas production by country showing that the United States and Russia dominate world production.

Chart: World natural gas production by country. Thanks to fracking, the United States (blue slice) now leads world production. Based on data from Natural Gas Production, Key World Energy Statistics 2017, International Energy Agency, p15.

Why does it matter where our fuel comes from? Oil powered the 20th-century economy, just as coal fueled the steam-powered 18th and 19th centuries. In recent decades, oil production has been dominated by countries in the Middle East, a politically unstable region. Many people worry over the risk of sourcing oil from volatile countries like Iraq (though, of course, such places are unstable partly because of the huge oil deposits they control). If gas-guzzling nations such as the United States can produce more of the fuel they use without relying on expensive imports, that can only be a good thing: it makes for better "fuel security" at home and a more secure, less volatile world beyond: if people have their own oil, they're less likely to fight wars over other people's—or so the argument goes. (One often-overlooked counter-argument is that while the US imports huge amounts of oil, much of US fracking is producing natural gas—an entirely different fuel that can't replace imported oil.)

From transporting goods to heating office blocks, energy adds costs to every product and service, so cheaper energy has knock-on economic benefits that go far beyond the petroleum industry. But despite the well-known laws of supply and demand, more gas and oil doesn't always, automatically, translate into lower energy prices. While energy consumers have certainly noticed a difference in the United States, experts believe that a planned large-scale expansion of fracking in the UK is unlikely to have any effect on home gas prices. That's partly because the UK is geologically more complex, so the oil and gas will be more expensive to recover, but also because Britain is part of a huge European gas market—and fracked gas will represent only a tiny proportion of the total.[6] Some believe the growing competitiveness of renewable energy will also undermine the economic case for fracking.[25]

The costs of fracking

Environmentalists have been quick to challenge the economic arguments for fracking on economic grounds, but they can also point to a whole raft of other objections. The three biggest concerns center on greenhouse gas emissions (the release of gases that cause climate change), water use, and pollution.

Emissions

By far the biggest problem is that fracking enlarges the world's supply of fossil fuels at a time when there is universal scientific agreement that we need to bring about a "substantial and sustained reduction" in global carbon dioxide emissions.[7] According to a recent study by Christopher McGlade and Paul Ekins of University College London, if we're to avoid dangerous climate change, "globally, a third of oil reserves, half of gas reserves and over 80 per cent of current coal reserves should remain unused"—in other words, most of the fossil fuel buried in the ground must stay there.[8] If we accept that analysis, there's no obvious reason for fracking hard-to-access oil and gas deposits. And the emissions argument doesn't stop there. Apart from increasing carbon dioxide emissions by boosting the supply of fossil fuels, the fracking process can also release trapped methane (a much more potent greenhouse gas) whether the oil or gas released at the same time is ever burned or not.

Oil and gas producers have a ready reply for the emissions argument. If we generate more natural gas by fracking, we could reduce our dependence on coal, a much dirtier fuel that typically produces twice as much CO2 (and a great deal more sulfur and nitrogen oxide pollution) when it's used for electricity generation, according to the US Environmental Protection Agency.[9] For that argument to hold, the fuel that fracking generates must displace coal and not more expensive, zero-emission renewable energy; also, it mustn't add to the total amount of fossil fuel that's burned (so it mustn't be burned as well as the coal it's claimed to replace, but instead of it). If methane leaks out from fracking wells, the CO2 benefit disappears, according to a study by Cornell University Professor Robert Howarth and his colleagues: "Compared to coal, the footprint of shale gas is at least 20 percent greater and perhaps more than twice as great on the 20-year horizon and is comparable when compared over 100 years."[10] The whole argument gets even more complex when we consider that coal produces sooty particulates (in the short term) that slows down the warming it produces. That means fracked gas may have a worse short-term effect on emissions than coal, according to Tom Wigley of the US National Center for Atmospheric Research [11], which is disastrous for the climate: emissions cuts need to happen now, not in decades time when it's too late.

So... fracked gas or coal? Environmentalists consider both options unacceptable. If we have to avoid drastic climate change by lowering emissions, the quickest and best way to do that is to shift away from fossil fuels altogether in favor of clean renewable energy and energy efficiency, not to engage in complex juggling tricks over which dirty fossil fuel is the "least worst" option.

Water use

Emissions are only one of many environmental objections to fracking. Remember that the basic principle is to fire powerful jets of water down wells to boost our "endangered" supply of oil and gas? But water itself is now a scarce resource in many regions. According to the United Nations: "Around 1.2 billion people, or almost one-fifth of the world's population, live in areas of physical [water] scarcity, and 500 million people are approaching this situation."[12] Even in the United States, people are relying increasingly on disappearing groundwater supplies—posing critical shortages in states such as California, Kansas, and Texas already.[13] So it could be argued that fracking simply swaps one problem for another.

Is that scaremongering or a wild exaggeration? Is our need for water trivial compared to our need for oil and gas? Perhaps not. According to the US EPA, "approximately 35,000 wells are fractured each year across the United States... the annual water requirement may range from 70 to 140 billion gallons... equivalent to the total amount of water used each year in... about 1 to 2 cities of 2.5 million people."[14] It takes up to 350,000 gallons of water to frack a coalbed methane formation and as much as five million gallons to frack a shale deposit.[15] Anywhere from 20–90 percent of the fracking fluid (the median amount is 70 percent or more) remains underground (the exact amount depends on the geology and site conditions), while the remainder is contaminated when it returns to the surface and may still, in effect, be lost forever.[15] Heavy water use in a water scarce world is a serious issue. The same issue applies to the sand that's often used as the proppant in fracking fluid: though anything but rare, it has to be mined or quarried from somewhere, opening up a further set of environmental impacts—from landscape destruction to the energy that diggers and trucks use in mining and transportation.[16]

Pollution

Water contained in a pond at a fracking site.

Photo: Wastewater contained in a pond at a fracking site. Photo by Bill Cunningham courtesy of US Geological Survey.

The quality of the water that spews back up from wells gives just as much concern as the quantity fired down them in the first place. Although chemicals make up only a minuscule fraction of the fracking fluid, the huge volumes of liquid used mean that, in absolute terms, very large amounts of water-polluting substances can be used in each well. The exact constituents of fracking fluid vary from well to well, according to the geology of the location, and are frequently kept secret for reasons of commercial confidentiality, but they typically include a toxic cocktail of acids, carcinogenic hydrocarbons, and volatile organic compounds (VOCs).[17] In all, several hundred different chemicals are known to have been used in fracking fluid; as an added headache, the high-pressure fracking fluid flushes other minerals up from the ground, including toxic "heavy metals" such as lead and radioactive rocky waste (sometimes named NORM—naturally occurring radioactive material). All this wastewater has to go somewhere. As we've already seen, the majority of fracking fluid usually remains underground, where anti-fracking campaigners believe it may threaten aquifers (the underground "rivers" that supply our drinking water); the rest returns to the surface, where it can pose a risk to soil, rivers, lakes, or other surface waters, if it spills or leaks from tanks, ponds, or containers.

The oil and gas companies who carry out fracking point out that aquifers lie relatively close to the surface (typically about 30–60m or 100–200ft), while oil and gas deposits are much deeper down (1500–2000m or 5000–6000ft), so the risks of contamination are smaller than might be expected. They also point out that they go to great lengths to seal wells with steel and concrete casing (sometimes multiple layers of it). Although the frackers claim that there have no cases of groundwater contamination to date, those claims are hotly disputed by local people living near wells who report water contamination. Even if there has been no contamination to date, it's impossible to be certain that none of the polluted fracking fluid that will be used in the many thousands of planned wells will ever leak into groundwaters at any point in the future. The whole point of fracking is that it drastically disrupts the geology underground so oil and gas can flow more freely. And if it disrupts the ground that much, the environmentalists argue, doesn't that raise a significant possibility of contamination? Studies of 141 Pennsylvania drinking water wells by Robert Jackson from Duke University, and his colleagues, appear to confirm this: "Overall, our data suggest that some homeowners living <1 km from gas wells have drinking water contaminated with stray gases."[18] In December 2016, following a long and exhaustive study, the US EPA finally concluded that fracking has indeed led to some drinking water contamination.[24] Contaminated water isn't the only form of pollution that occurs near fracking sites. The drilling and piping equipment used in oil and gas fields inevitably leaks some toxic, volatile hydrocarbons into the air, causing air pollution in local communities. Tanks and lagoons where flowback from wells is stored can also give rise to air pollution.[19]

Water and air pollution raise a whole series of concerns, from the effects on ecosystems to the possible harm to human health—everything from respiratory illnesses and skin complaints to miscarriages and birth defects. And it's not just local communities, often portrayed as self-interested NIMBYs, who are at risk. Around 180,000 people work in the oil and gas extraction industry in the United States alone (half of them in production or nonsupervisory roles), and these are the people most at risk from direct contact with toxic chemicals or inhalation of air pollution.[20]

Other issues

Trucks, pumps, well heads, and other equipment at a large fracking site.

Photo: Fracking can be hugely disruptive to local communities. This is a typical fracking operation, with dozens of trucks and tankers parked at a Marcellus shale gas field in Pennsylvania. Photo by Doug Duncan courtesy of US Geological Survey.

Justified or not, a variety of other concerns have been raised about fracking. When gas company Caudrilla sunk some experimental fracking wells in the English county of Lancashire, prompting minor earthquakes, there were howls of protest over safety; recent earthquakes in Canada have also been attributed to fracking.[21] What if deep drilling damaged people's homes or offices? Who would pay? There are property rights issues too. If wells are bored horizontally, directly underneath someone's home, doesn't that person have a legitimate right to claim any oil or gas found there? What about all the heavy trucks needed to cart equipment and supplies through the towns and villages where wells are being sunk? How will that affect the quality of life in local communities? And, with all that highly volatile oil and gas moving around, what about safety? Fears were heightened in 2013 when a freight train hauling 72 wagons of fracked crude oil crashed and exploded at Lac Mégantic in Canada, killing 47 people and demolishing 40 buildings.[22]

Economy versus environment?

Most environmentalists see fracking as a dangerous distraction from the urgent need to reduce emissions and shift our society away from what they describe as its "addiction" to fossil fuels. But is the issue really so black and white? All of us rely on transportation and home heating: fossil fuels still provide about 80 percent of our total energy.[23] Even if you heat your home sustainably and walk or cycle wherever you go, you still buy shoes, clothes, TVs, toys, and all manner of gadgets made in energy-intensive factories and shipped halfway round the world. Even if you never buy a thing, you still keep your money in a bank that (in all probability) invests in oil and gas companies. Maybe you go to school (or send your kids there) in big old buses powered by gas-guzzling diesel engines? Perhaps all you ever do is read books—but even they have to be printed and transported. Everything has an energy impact: however hard you try, it's very hard not to consume energy every day of your life. And even if you could succeed in living a squeaky clean and green life, it's very sobering to remember that there are over seven billion more people packed tight on Earth. Most of them have higher priorities than saving the planet—and most of those priorities (running a home, building a business, raising a family) use large amounts of energy. In short, in a world so heavily dependent on fossil fuels, there are very compelling economic reasons for trying to boost supplies of gas and oil.

Cars waiting at a gas station in England.

Photo: There are over a billion cars on the planet, most powered by gasoline (petrol). Once easy-to-reach petroleum fields have been exhausted, where will tomorrow's oil come from, if not from fracking shale and other hard-to-reach deposits?

But the trouble with climate change is that we can't see or even imagine the damage it may cause years, decades, or centuries into the future. What if large parts of the planet become completely unlivable? What if entire low-lying islands disappear to rising seas? What if hugely important cities like New York and London suddenly find themselves underwater? What if millions of people die horrible, lingering deaths through droughts, floods, or heatwaves? No-one can imagine a future of runaway climate change—and most of us, still sunk in denial, do our best not to try.

When there's overwhelming scientific agreement that burning fossil fuels is threatening climate catastrophe, why would we possibly want to raise the stakes by fracking oil and gas deposits so we can burn even more? With a few years of intensive effort—an Apollo program for the planet—we could substantially increase the energy efficiency of our buildings, transportation, and electricity production. If we could shift away from fossil fuels entirely so 80 percent of our energy came from renewables instead, there would be no need to pursue fracking or put our future on Earth at risk. Investment in renewables and efficiency would create jobs, just like fracking, and lower business costs, just as fracking (in a best-case scenario) is claimed to do.

Though the heated debate over fracking is sure to continue, it's far from certain that economic arguments must always trump environmental ones. Environmentalists argue that we don't have to choose between jobs and planet, oil wells and green fields, clean air and economic prosperity: for greens, it's a specious argument and a false choice when the real—and only choice—is between the survival of humankind and a climate catastrophe. But even environmentalists drive cars, wear shoes shipped from China, go to school in diesel buses, and seek treatment in energy-hungry hospitals fired by fossil fuels. The circle has to be squared somehow—and quickly: we have to meet humankind's ever-growing energy needs without destroying the planet on which we all depend. And time is running out.

References

  1.    Shale gas production drives world natural gas production growth, US Energy Information Administration, August 15, 2016.
  2.    Natural Gas Production, Key World Energy Statistics 2017, International Energy Agency, p15. For 2017, the United States represents 20.7 percent of world natural gas production.
  3.    The EIA chart US Price of Natural Gas Delivered to Residential Customers (displayed as an annual average) shows a decline in price from a peak of $13.89 per thousand cubic feet in 2008 to $10.38 per thousand cubic feet in 2015: a fall of about a quarter. For commercial customers, the decline was from $12.23 in 2008 to $7.91 in 2013: a fall of 35 percent.
  4.    US oil production is still going through the roof, Akin Oyedele, Yahoo Finance News, February 5, 2015.
  5.    Oil and gas industry employment growing much faster than total private sector employment, US Energy Information Administration, August 8, 2013.
  6.    Lord Browne: fracking will not reduce UK gas prices, Damian Carrington, The Guardian, November 29, 2013.
  7.    Humans blamed for climate change, Richard Black, BBC News, February 2, 2007. More recently, the IPCC said: "Limiting climate change would require substantial and sustained reductions in greenhouse gas emissions which, together with adaptation, can limit climate change risks." IPCC Climate Change 2014 Synthesis Report: Summary for Policymakers, p8.
  8.    The geographical distribution of fossil fuels unused when limiting global warming to 2°C, Christophe McGlade and Paul Ekins, Nature, January 7, 2015.
  9.    "Compared to the average air emissions from coal-fired generation, natural gas produces half as much carbon dioxide, less than a third as much nitrogen oxides, and one percent as much sulfur oxides at the power plant." Natural Gas, US Environmental Protection Agency, September 25, 2013. [Archived via the Wayback Machine.]
  10.    Methane and the greenhouse-gas footprint of natural gas from shale formations, Robert Howarth et al, Climatic Change, June 2011.
  11.    Coal to gas: the influence of methane leakage, Tom Wigley, Climatic Change, October 2011.
  12.    UN Water scarcity, November 24, 2014. (Last checked December 3, 2017).
  13.    If You Think the Water Crisis Can't Get Worse, Wait Until the Aquifers Are Drained, Dennis Dimick, National Geographic, August 19, 2014.
  14.    Draft Plan to Study the Potential Impacts of Hydraulic Fracturing on Drinking Water Resources, US EPA, February 2011, p19. [PDF format]
  15.    A quick online search for the terms "fracking percent of water remains underground" brings up a range of estimates from 50–95 percent in both websites and books. The EPA says "The median amount of fluid returned to the surface is 30 percent or less," according to Chapter 7: "Produced Water Handling" of Hydraulic Fracturing for Oil and Gas: Impacts from the Hydraulic Fracturing Water Cycle on Drinking Water Resources", US EPA, December 2016.
  16.    Sand Mining Takes Toll on Wisconsin As Fracking Escalates Nationwide, EcoWatch, August 4, 2014.
  17.    FracFocus: What chemicals are used?.
  18.    Higher Levels of Stray Gases Found in Water Wells Near Shale Gas Sites, Duke University Press Release, June 24, 2013 and Increased stray gas abundance in a subset of drinking water wells near Marcellus shale gas extraction by Robert B. Jackson et al.
  19.    Fracking and air pollution, SourceWatch, accessed February 5, 2015.
  20.    Oil and Gas Extraction NAICS 2011, Bureau of Labor Statistics. Last checked December 3, 2017.
  21.    Fracking tests near Blackpool 'likely cause' of tremors, BBC News, November 2, 2011. In Canada, a Direct Link Between Fracking and Earthquakes by Henry Fountain. The New York Times, November 17, 2016.
  22.    Lac-Mégantic oil train disaster inquiry finds string of safety failings, The Guardian, August 20, 2014.
  23.    In 1973, coal, natural gas, and oil provided 86.7 percent of the world's "total primary energy supply"; in 2014, the same fossil fuels were still providing 81.1 percent of our energy. A big hefty expansion of nuclear power and a small increase in renewables accounts for the difference. Key World Energy Statistics 2016, International Energy Agency, p6. [PDF format]
  24.    Reversing Course, EPA Says Fracking Can Contaminate Drinking Water by Coral Davenport. The New York Times, December 13, 2016. For more on this, see Hydraulic Fracturing for Oil and Gas: Impacts from the Hydraulic Fracturing Water Cycle on Drinking Water Resources", US EPA, December 2016.
  25.    Boom in renewables weakens fracking's case in UK, says Tory MP by Adam Vaughan. The Guardian, November 26, 2017.
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