The term "fracking" summarizes the English term and means the breaking up (English to fracture) of the ground with water pressure.
For this purpose, a mixture of water, sand and various chemicals is pumped into the target formation from the very low-permeability rock during fracking.
Cracks form through which the gas present in the soil can escape.
The type of rock in the soil determines whether and how fracking is used.
Conventional gas deposits are found, for example, in porous sandstone.
The gas can flow more easily to the production wells and fewer wells are required.
In unconventional reservoirs, the gas is trapped in dense rock.
In order for the gas to be pumped, pathways must be created.
These deposits are found, for example, in shale, clay, marl and coal seam rock.
According to these deposits, this process is called unconventional fracking.
"So-called conventional fracking in natural gas production from sandstone has been used in Germany for many years and has been tried and tested over many years," says Prof. Dr.
Charlotte Krawczyk.
She is a geophysicist at the German Research Center for Geosciences in Potsdam and chair of the expert commission for fracking, which was set up by the federal government in 2018.
Companies in Germany have been extracting gas using conventional fracking since 1961.
Even if there hasn't been any drilling since 2012, gas can still be extracted from the wells today.
Unconventional fracking, on the other hand, has been banned in Germany since 2017.
With a view to autumn, the first politicians are shaking up this ban.
According to an estimate by the Federal Institute for Geosciences and Natural Resources (BGR) from 2016, between 320 billion and 2030 billion cubic meters of gas are stored in unconventional deposits such as shale rock in Germany.
Germany currently consumes around 90 billion cubic meters of gas annually.
"At best, we could theoretically cover Germany's gas requirements for almost 25 years," says Prof. Dr.
Moh'd M. Amro, engineer at the Bergakademie Freiberg.
According to the BGR, the largest deposits of shale gas are in North Rhine-Westphalia, Lower Saxony and on the island of Rügen.
How safe is the fracking process?
But the 2017 moratorium was based on multiple concerns about the risks of fracking.
In a report from 2014, the Federal Environment Agency named various potential hazards: the chemicals used in fracking could get into the groundwater, the drilling could cause earthquakes and the particularly climate-damaging gas methane could escape from the drilling.
This was flanked by a public movement against fracking, which was triggered by fracking accidents in the USA.
For example, chemicals from the fracking fluid got into the groundwater there.
In addition, interest on the part of the industry also fell due to the falling crude oil prices and the associated falling profit expectations.