WEBVTT 00:00:00.658 --> 00:00:04.800 What is hydraulic fracturing – or fracking ? 00:00:04.800 --> 00:00:09.800 Since the industrial revolution our energy consumption has risen unceasingly. 00:00:09.800 --> 00:00:17.383 The majority of this energy consumption is supplied by fossil fuels like coal or natural gas. 00:00:17.383 --> 00:00:21.800 Recently there has been a lot of talk about a controversial method of extracting natural gas: 00:00:21.800 --> 00:00:25.800 Hydraulic fracturing or fracking. 00:00:25.800 --> 00:00:30.577 Put simply, fracking describes the recovery of natural gas from deep layers inside the earth. 00:00:30.577 --> 00:00:34.632 In this method, porous rock is fractured by the use of water, sand and chemicals 00:00:34.632 --> 00:00:39.497 in order to release the enclosed natural gas. 00:00:39.497 --> 00:00:42.777 The technique of fracking has been known since the 1940s. 00:00:42.777 --> 00:00:48.856 Nonetheless, only in the last ten years has there been quite a “fracking boom”, 00:00:48.856 --> 00:00:51.134 especially in the USA. 00:00:51.134 --> 00:00:57.633 This is because most conventional natural gas sources in America and on the European continent have been exhausted. 00:00:57.633 --> 00:01:03.299 Thus prices for natural gas and other fuels are rising steadily. 00:01:03.299 --> 00:01:10.658 Significantly more complicated and expensive methods, like fracking, have now become attractive and profitable. 00:01:10.658 --> 00:01:17.098 In the meantime, fracking has already been used more than a million times in the USA alone. 00:01:17.098 --> 00:01:22.498 Over 60% of all new oil and gas wells are drilled by using fracking. 00:01:22.498 --> 00:01:26.800 Now let’s take a look at how fracking actually works: 00:01:26.800 --> 00:01:31.800 First, a shaft is drilled several hundred meters into the earth. 00:01:31.800 --> 00:01:37.097 From there, a horizontal hole is drilled into the gas-bearing layer of rock. 00:01:37.097 --> 00:01:42.098 Next, the fracking fluid is pumped into the ground using high-performance pumps. 00:01:42.098 --> 00:01:46.049 On average, the fluid consists of 8 million liters of water 00:01:46.049 --> 00:01:50.133 which amounts to about the daily consumption of 65,000 people. 00:01:50.133 --> 00:01:55.656 plus several thousand tons of sand and about 200,000 liters of chemicals. 00:01:55.656 --> 00:02:01.048 The mixture penetrates into the rock layer and produces innumerable tiny cracks. 00:02:01.048 --> 00:02:05.264 The sand prevents the cracks from closing again. 00:02:05.264 --> 00:02:07.965 The chemicals perform various tasks 00:02:07.965 --> 00:02:10.465 among other things, they condense the water, 00:02:10.465 --> 00:02:11.965 kill off bacteria 00:02:11.965 --> 00:02:14.884 or dissolve minerals. 00:02:14.884 --> 00:02:18.216 Next, the majority of the fracking fluid is pumped out again. 00:02:18.216 --> 00:02:22.050 And now the natural gas can be recovered. 00:02:22.050 --> 00:02:26.337 As soon as the gas source is exhausted, the drill hole is sealed. 00:02:26.337 --> 00:02:32.578 As a rule, the fracking fluid is pumped back into deep underground layers and sealed in there. 00:02:32.578 --> 00:02:37.216 However, fracking is also associated with several considerable risks. 00:02:37.216 --> 00:02:41.099 The primary risk consists in the contamination of drinking water sources. 00:02:41.099 --> 00:02:44.097 Fracking not only consumes large quantities of fresh water, 00:02:44.097 --> 00:02:49.216 but in addition the water is subsequently contaminated and is highly toxic. 00:02:49.216 --> 00:02:56.216 The contamination is so severe that the water cannot even be cleaned in a treatment plant. 00:02:56.216 --> 00:02:59.965 Even though the danger is known and theoretically could be managed, 00:02:59.965 --> 00:03:06.337 in the USA already sources have been contaminated due to negligence. 00:03:06.337 --> 00:03:09.616 No one yet knows how the enclosed water will behave in the future, 00:03:09.616 --> 00:03:14.298 since there have not yet been any long-term studies on the subject. 00:03:14.298 --> 00:03:17.576 The chemicals used in fracking vary from the hazardous to the 00:03:17.576 --> 00:03:24.738 extremely toxic and carcinogenic, such as benzol or formic acid. 00:03:24.738 --> 00:03:32.577 The companies using fracking say nothing about the precise composition of the chemical mixture. 00:03:32.577 --> 00:03:39.178 But it is known that there are about 700 different chemical agents which can be used in the process. 00:03:39.178 --> 00:03:43.537 Another risk is the release of greenhouse gases. 00:03:43.537 --> 00:03:47.418 The natural gas recovered by fracking consists largely of methane, 00:03:47.418 --> 00:03:53.465 a greenhouse gas which is 25 times more potent than carbon dioxide. 00:03:53.465 --> 00:03:57.457 Natural gas is less harmful than coal when burned. 00:03:57.457 --> 00:03:59.383 But nonetheless, the negative effects of fracking 00:03:59.383 --> 00:04:02.134 on the climate balance are overall greater. 00:04:02.134 --> 00:04:07.496 Firstly, the fracking process requires a very large consumption of energy. 00:04:07.496 --> 00:04:11.738 Secondly, the drill holes are quickly exhausted and it is necessary to drill 00:04:11.738 --> 00:04:16.633 fracking holes much more frequently than for classical natural gas wells. 00:04:16.633 --> 00:04:24.496 In addition, about 3% of the recovered gas is lost in the extraction and escapes into the atmosphere. 00:04:24.496 --> 00:04:27.258 So how is fracking and its expected benefits to be assessed 00:04:27.258 --> 00:04:31.497 when the advantages are balanced against the disadvantages? 00:04:31.497 --> 00:04:34.258 When properly employed, this technique offers one way 00:04:34.258 --> 00:04:41.050 in the short to medium term for meeting our demand for lower-cost energy. 00:04:41.050 --> 00:04:44.633 But the long-term consequences of fracking are unforeseeable 00:04:44.633 --> 00:04:49.258 and the risk to our drinking water thus should not be underestimated.