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What is hydraulic fracturing – or fracking ?
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Since the industrial revolution our energy consumption has risen unceasingly.
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The majority of this energy consumption is supplied by fossil fuels like coal or natural gas.
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Recently there has been a lot of talk about a controversial method of extracting natural gas:
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Hydraulic fracturing or fracking.
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Put simply, fracking describes the recovery of natural gas from deep layers inside the earth.
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In this method, porous rock is fractured by the use of water, sand and chemicals
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in order to release the enclosed natural gas.
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The technique of fracking has been known since the 1940s.
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Nonetheless, only in the last ten years has there been quite a “fracking boom”,
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especially in the USA.
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This is because most conventional natural gas sources in America and on the European continent have been exhausted.
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Thus prices for natural gas and other fuels are rising steadily.
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Significantly more complicated and expensive methods, like fracking, have now become attractive and profitable.
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In the meantime, fracking has already been used more than a million times in the USA alone.
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Over 60% of all new oil and gas wells are drilled by using fracking.
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Now let’s take a look at how fracking actually works:
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First, a shaft is drilled several hundred meters into the earth.
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From there, a horizontal hole is drilled into the gas-bearing layer of rock.
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Next, the fracking fluid is pumped into the ground using high-performance pumps.
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On average, the fluid consists of 8 million liters of water
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which amounts to about the daily consumption of 65,000 people.
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plus several thousand tons of sand and about 200,000 liters of chemicals.
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The mixture penetrates into the rock layer and produces innumerable tiny cracks.
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The sand prevents the cracks from closing again.
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The chemicals perform various tasks
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among other things, they condense the water,
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kill off bacteria
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or dissolve minerals.
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Next, the majority of the fracking fluid is pumped out again.
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And now the natural gas can be recovered.
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As soon as the gas source is exhausted, the drill hole is sealed.
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As a rule, the fracking fluid is pumped back into deep underground layers and sealed in there.
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However, fracking is also associated with several considerable risks.
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The primary risk consists in the contamination of drinking water sources.
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Fracking not only consumes large quantities of fresh water,
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but in addition the water is subsequently contaminated and is highly toxic.
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The contamination is so severe that the water cannot even be cleaned in a treatment plant.
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Even though the danger is known and theoretically could be managed,
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in the USA already sources have been contaminated due to negligence.
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No one yet knows how the enclosed water will behave in the future,
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since there have not yet been any long-term studies on the subject.
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The chemicals used in fracking vary from the hazardous to the
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extremely toxic and carcinogenic, such as benzol or formic acid.
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The companies using fracking say nothing about the precise composition of the chemical mixture.
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But it is known that there are about 700 different chemical agents which can be used in the process.
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Another risk is the release of greenhouse gases.
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The natural gas recovered by fracking consists largely of methane,
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a greenhouse gas which is 25 times
more potent than carbon dioxide.
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Natural gas is less harmful than coal when burned.
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But nonetheless, the negative effects of fracking
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on the climate balance are overall greater.
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Firstly, the fracking process requires
a very large consumption of energy.
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Secondly, the drill holes are quickly exhausted and it is necessary to drill
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fracking holes much more frequently than for classical natural gas wells.
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In addition, about 3% of the recovered gas is lost in the extraction and escapes into the atmosphere.
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So how is fracking and its expected benefits to be assessed
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when the advantages are balanced against the disadvantages?
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When properly employed, this technique offers one way
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in the short to medium term for meeting our demand for lower-cost energy.
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But the long-term consequences of fracking are unforeseeable
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and the risk to our drinking water thus should not be underestimated.
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