CO2 disposal A repository for greenhouse gases

Since the federal government, according to an evaluation report published in 2022, has considered the capture and disposal of carbon dioxide (carbon capture and storage, CCS) “on the megaton scale” to be necessary in order to achieve the climate goals, the debate about the technology has been back. It is undisputed among experts and in large parts of society that the emission of carbon dioxide (CO₂) has to be drastically reduced, but that should not be enough to keep the temperature rise below two degrees Celsius. That is why many of the scenarios considered by the Intergovernmental Panel on Climate Change (IPCC) require additional gas capture and long-term storage. A current publication, initiated by four IPCC authors, also shows how urgently solutions are needed to remove the greenhouse gas from the atmosphere.

There was already a broad debate about CCS in Germany in the early 2010s. At that time, the main focus was on making coal-fired power »clean«: the CO released during combustion₂ should be separated and injected underground to prevent it from escaping into the atmosphere in the first place. There was much disagreement centered around potential leaks and their consequences, high costs and competition for the energy transition – after all, this form of CCS would lock coal in as a long-term energy source. The project seemed hopeless, the plans were stopped, CCS was banned.

The current discussion is mainly about CO₂-Industrial sources such as cement, glass, lime, waste and chemicals. In principle, the process can also be used for separated carbon dioxide from the combustion of biomass and for carbon dioxide that is removed from the ambient air with special systems. These options are not that well developed, but are often included in CCS scenarios, which sometimes complicates the discussion. The point here is whether carbon dioxide can be separated from so-called point sources in industry – directly in front of the chimney – and permanently locked away in deep layers …