By Marleen Wiegmann, tagesschau.de
Germany has made a commitment: the country should be climate-neutral by 2045. But emissions are not falling fast enough to meet this target. Researchers are therefore calling for CO2 to be reduced in other ways in addition to the savings. In Germany, a well-known technology was able to celebrate a comeback: Carbon Capture and Storage (CCS), in German: the separation and underground storage of CO2.
Economics and Climate Protection Minister Robert Habeck's trip to Norway two weeks ago could be an indication of this. Because CO2 from Germany is to be transported to Norway in the future and stored there under the seabed. The federal government wants to develop a carbon management strategy before the end of this year and remove legal hurdles that are currently preventing the transport of CO2 to Norway.
Use of old natural gas fields
With CCS, CO2 from coal-fired power plants or cement works, for example, is separated, liquefied and then transported to the storage site via pipeline, ship or truck. This can be in deep rock strata on land (on-shore) or under the seabed (off-shore). Old natural gas fields are also used to introduce the CO2, as gases have already been stored here for at least 10,000 years.
CO2 capture is currently being pursued primarily in industrial companies. There are various methods that start at different points in the industrial process. They either remove the CO2 before or after industrial processing, or treat the air used for combustion.
Filtering it out of the atmosphere is currently still very expensive and energy-intensive. According to Habeck, CCS should be an interim solution for unavoidable emissions that cannot currently be avoided.
Unavoidable emissions in cement production
"Coal-fired power plants are no longer an issue when it comes to CO2 separation," says Bernd Epple, Head of the Department of Energy Systems and Technology at the Technical University in Darmstadt. Because they no longer have a future – and investments in technology with an expiry date are not economically worthwhile.
It's different in cement works, for example. CO2 is inevitably produced there and concrete will continue to be a popular building material. According to a WWF report from 2019, production causes a total of eight percent of all greenhouse gas emissions worldwide.
No industrial use in Germany
In the long term, however, CO2 should not only be exported, but also stored in Germany. There are already possible places for this: According to the Federal Institute for Geosciences and Natural Resources (BGR), there is room for several billion tons of CO2 in the deeper layers of rock in the German North Sea. However, they are hardly used at the moment.
Because more than ten years ago there was already a heated discussion about the storage of CO2 in Germany. At that time, coal-fired power plants in particular wanted to give themselves a greener coat of paint. Citizen initiatives took action against it. As a result, there is no industrial use of CCS in Germany and only a few research projects.
Geologists believe technology is safe
But even today, when it is no longer about the ecological balance of coal-fired power plants, there is still criticism of CCS. Karsten Smid is Greenpeace's climate and energy expert. Ten years later, CCS is still not an option for him. Rather, he fears that the CO2 could escape again through leaks and earthquakes.
Klaus Wallmann sees it differently. He has been researching CCS at the GEOMAR Helmholtz Center for Ocean Research in Kiel for years and is of the opinion: "We need CCS to curb climate change." Many of his colleagues put it the same way. CCS is a means of becoming climate-neutral. This means that the amount of emitted and removed emissions balance out. This can happen, for example, through reforestation or technologies such as CCS. The Intergovernmental Panel on Climate Change therefore also includes CCS as a means of combating climate change.
In the event of leaks, little impact on the ecosystem
Wallmann was also coordinator for the EU-funded project ECO2. A team of scientists examined Norwegian CO2 deposits for leaks – they found none. Should gas nevertheless escape, the impact on the organisms would be minimal, according to Wallmann. "If CO2 escapes from a leak, it dissolves near the bottom. The water becomes acidic as a result, and that has a negative impact on biodiversity. However, the radius of damage is small."
Sebastian Bauer is a geoscientist at the University of Kiel and is involved in the GEOSTOR project. Among other things, the team wants to recalculate the geological storage capacity for CO2 below the North Sea. Bauer already did intensive research on CCS ten years ago. He too thinks that the ambitious climate targets cannot be achieved without CCS. "But that was the case 15 years ago." According to Bauer, possible risks are closely related to the respective location for the storage of CO2.
Pilot site in Ketzin – 67,000 tons of CO2 injected
In the case of possible CCS locations, the selection of suitable locations is particularly important. With the storage of CO2 in deep rock strata under land, there are more protected assets – such as buildings and groundwater. The latter in particular could be contaminated when CO2 was injected into the soil.
A pilot project at Ketzin showed that storing CO2 on-shore can still be successful. Between 2008 and 2013, scientists from the German Research Center for Geosciences (GFZ) in Potsdam injected around 67,000 tons of CO2 into the ground. Subsequent monitoring took place over four years. Since then it has been considered one of the flagship projects for storing CO2.
Primary goal: avoidance of emissions
If Habeck has his way, Germany will soon be pumping part of its CO2 to Norway. The Economics Minister considers the use of CCS necessary so that Germany can achieve the goal of climate neutrality by 2045. This is also underlined by the evaluation report on the Carbon Dioxide Storage Act, which also regulates CCS. However, the ultimate goal is still the reduction of emissions.