Why storing carbon dioxide makes sense

Firstly, the transition to greenhouse gas neutrality, as set out in the German Climate Change Act, will not be sufficient to achieve the climate goals in the long term. The IPCC’s analyses show that CO₂ will have to be actively removed from the atmosphere from around 2060/2070 at the latest in order to achieve the 1.5 or 2 °C goal, respectively. Secondly, it is very expensive to avoid the “last tons of CO₂”, for example in the chemical industry or in aviation. In these cases, CO₂ capture and storage is a cheaper alternative, as analyses by the IEK-3 of the Forschungszentrum Jülich have shown. However, this only applies to emissions that are difficult to capture or basic chemicals that are hard to substitute. Thirdly, some CO₂ emissions are unavoidable due to chemical reactions during material conversion in production, particularly in cement, quicklime and glass production. Fourthly, the certain intermediate steps of the energy transition are unlikely to be achieved in time. Gas-fired power plants, for example, which are supposed to compensate for lulls of renewable energy supply, might not  get supplied  with hydrogen in time. Hence, creating an alternate pathway by using natural gas intermediately will contribute to a more robust transition. However, such transitional arrangements should be subject to clear phase-out rules or corresponding costs.

How can CO₂ be captured and stored? CO₂ can be biologically captured and stored through reforestation and peatland restoration, as well as through the use of biomass with subsequent capture and storage. CO₂ can be captured after the combustion using proven techniques at localized, i.e. large, constant energy consumers. Direct Air Capture (DAC) of CO2 from the air though, is new technology that is being investigated intensely by Helmholtz. In the Helmholtz project DACstorE, researchers investigate fundamental processes, develop new capture methods, design plants, identify potential sites worldwide for later operation. Moreover,  storage sites are identified and investigated. Particular attention is being paid to the safety of storage facilities, for example through close monitoring. This technology can fill the gap described above.

It is appreciated that the German government’s carbon management strategy focuses on difficult and unavoidable emissions and the transition to renewable energies. As a further step it will be important to address the long-term perspective in a separate strategy.