Carbon capture and storage (CCS) as a solution to emissions?

Since COP28 at the latest, the term CCS, i.e._{CO2 storage} and capture, has often been used in connection with the fight against global warming. But what is CCS anyway? How does it work? Is it already in use or a dream of the future?

What is CCS?

CCS(carbondioxide captureand storage) refers to the technically complex capture and storage of_CO2 directly from the environment or from other sources on land or in the seabed, with the aim of reducing emissions. The carbon dioxide comes either from fossil energy supply plants, from industrial plants (steel, lime, cement, chemical industry, refineries) or from the use of biomass to generate energy, according to the Federal Environment Agency, or directly from the environment. This is filtered, processed, transported to an underground storage site and stored for the long term.

This deposit must be a gas-tight geological formation, such as saline aquifers (porous saltwater-bearing rock layers on land or under the seabed), depleted oil and gas fields or coal seams.

Is CCS already in use?

Yes, according to the Federal Institute for Geosciences and Natural Resources (BGR), this technology has already been in use in the North Sea off the coast of Norway since 1996 (in the "Sleipner Project").

Dozens of other_{CO2 storage facilities} have been put into operation since then, mainly in North America.

In Iceland, too,_CO2 is captured and stored both from the air and from industrial waste gases. In March of this year, a_CO2storage facility was put into operation in Denmark with the "Greensand" project.

CO₂ storage facility off the coast of Denmark active since Wednesday

An up-to-date overview of storage activities worldwide can be found, for example, in the "_CO2RE" database of the Global CCS Institute.

Process types

There are different types of processes with which the_CO2 is_captured , including

• Post-combustionafter combustion in a_{CO2 scrubber} from the exhaust gas
• Pre-combustionSeparation after coal gasification
• OxyfuelCombustion in an oxygen atmosphere

"All three processes are being developed in parallel and have been implemented in pilot plants. Each of the technologies has specific advantages and disadvantages compared to the others. It is still completely unclear which technology (and whether any of them) could be used on an industrial scale. " writes Wikipedia.

What are the problems with CCS?

• Capture, transportation and storage are cost-intensive and require enormous amounts of energy.
• In addition, there are high_CO2 emissions during transportation by truck or ship.
  
• If the toxic gas escapes from the deposits, this can lead to heavy metal contamination in the groundwater
• According to a Harvard study, grouting also leads to a high probability of minor earthquakes in the reservoir area
• Conflicts of use may arise
• Comprehensive monitoring is necessary. As techniques for comprehensive monitoring are not yet available, there is a considerable need for research in this area
• Liability in the event of leaks is a contentious issue

Legal matters

CCS has been banned in Austria since 2011. In Germany, a law has been in force since 2012 that sets a maximum storage volume for Germany of four million tons of_CO2 per year in total and 1.3 million tons per year per storage facility, as well as a state clause that allows individual federal states the option of a general ban on_{CO2 storage} on their territory (source: Wikipedia).

Is CCS a solution to the climate crisis?

According to the IPCC, CCS is the most expensive, ineffective and risky option. The enormous technical effort, the high energy input, the high costs and the additional_{CO2 input}- all this together bears no relation to the amount stored. The potential environmental damage has also not yet been sufficiently researched. Many CCS projects have been abandoned. We need to reduce the_{amount of CO2} by abandoning fossil fuels instead of simply doing it and then trying to contain the effects with CCS. This is often used as an argument by oil and gas producers to avoid reducing production volumes, which we urgently need in order to achieve the energy transition.