Fracking row
October 13, 2011
Hydraulic fracturing - commonly known as 'fracking' - is a technique used to get natural gas from difficult places like coal beds or shale.
Fracking has been around for decades and uses water pressure to crack underground rocks. It is going through a boom in the United States, where mining companies say high energy prices are forcing them to look for more unconventional deposits of gas.
In Europe, they're also eyeing potential new deposits, but they're meeting a mixed response.
"The technique has been tested and approved," says ExxonMobil's Hanover-based spokeswoman, Ritva Westendorf-Lahouse. "It has been used in Germany for 50 years."
The oil and gas company ExxonMobil occasionally uses fracking to boost production, but it also uses it to extract "tight gas," which comes from new sources in unconventional places.
Westendorf-Lahouse points to a sandy sample on her desk.
"This is sandstone from a conventional gas field," she says. "If you look closely, you can see tiny rock pores - they usually contain gas. And all of these pores are connected with each other."
Because the pores are connected, the gas can easily find its way up to a bore hole. It's different in unconventional gas deposits.
"This shale looks a bit like marble plate," says Westendorf-Lahouse. "There are also - it's almost impossible for the human eye to see - pores containing natural gas. But they are not connected with each other. So we fracture the rock in a controlled manner to help the gas come to the surface."
Fracking rock
High pressured water is injected into the rock at about 1,000 to 5,000 meters below the earth's surface. Then, sand is sent down to fill up the cracks and make sure they stay open. Later, the gas passes through the sand to reach the surface.
Though fracking isn't a new techniques, the sources ExxonMobil wants to drill are.
There are three different kinds of unconventional gas deposits: Shale, coal seam and a certain kind of sandstone from which "tight gas" is extracted.
ExxonMobil has extracted tight gas in the German town of Söhlingen since the 1990s. It now wants to drill shale and coal seam fields in the states of North Rhine Westphalia and in Lower Saxony.
Growing opposition
Critics in Germany say they are concerned about the effects of fracking on people's health and the environment. They say Germany should learn from experience in the US - where fracking is big.
Martin Knäpper, who lives in Hamm in North Rhine Westphalia, joined a citizens' initiative against fracking when he read about plans to extract gas from unconventional fields in his area by a company called HammGas.
"The more research I did online, I (realized fracking had had) disastrous effects for the environment in the US," says Knäpper.
"Thousands of liters of chemicals are pumped into the soil," he says, "it breaks up the rocks and methane gets into the ground water. It is a very risky enterprise."
There are a growing number of action groups against fracking in North Rhine Westphalia and Lower Saxony. One group recently handed a petition with 13,000 signatures to the German parliament to urge the government to ban fracking.
They are especially concerned about the chemicals which are added to the process to make it work.
Chemical cocktail
The sand and water, which are sent underground to fracture a rock, do not mix well. So drilling companies add chemicals to make the sand and water mix into a viscous fluid and prevent the sand from settling.
But once the fluid is underground, the process is reversed to ensure the sand stays underground and allow the water to be pumped back up and give way to the natural gas.
So a second chemical is used to dilute and separate the fluid.
Other chemicals are also introduced to stop rocks from bulging, and biocides stop bacteria and yeast from entering the fluid.
"The amount of chemical additives is very small, sometimes less than 0.2 percent, and in others two to five percent," says ExxonMobil's Westendorf-Lahouse.
"But the fluid is neither dangerous to the environment nor poisonous," she says. "We don't have to declare it under the Chemicals Act - it is not a dangerous substance."
ExxonMobil's own figures are incongruous. According to its website, in a fracking exercise in Goldenstedt in Lower Saxony, the company used about six million kilograms of fluid, containing about 93,000 kilograms of chemicals, which contained "58,034 kilograms of hazardous chemicals."
Setting fire to water
In 2010, a documentary about fracking in the US claimed water had been so heavily polluted with methane through the process that it was possible to set fire to the water.
ExxonMobil insists it is impossible for fracking fluid or natural gas to get into drinking water.
"The drilling is not just a hole in the ground, it's like a telescopic construction," says Westendorf-Lahouse. "The drilling is secured by several layers of steel and cement."
Campaigner Martin Knäpper is not convinced.
"No one knows what's going to happen in the next 15 years," says Knäpper.
"Will there be movements in the ground, will there be new cracks, will the pipes corrode, will the concrete become brittle? The risk are unpredictable!"
The Helmholtz Center for Environmental Research in Leipzig is currently conducting a new study into the safety and environmental impacts of drilling at unconventional sites.
Their research is focused on fracking in shale and coal seam, but not in tight gas fields, where the fracking is often used.
Author: Brigitte Osterath / sst
Editor: Nathan Witkop