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