Different carbon removal approaches in Germany have been examined to determine which ones have the highest potential to extract carbon from the air. Researchers from the Helmholtz Climate Initiative‘s Net Zero 2050 Cluster have identified the approaches most suitable for carbon removal in Germany.
Their research concludes that natural sinks can be expanded in the short term and CO2 reductions are thus implemented faster, while high-tech methods can reduce greenhouse gases only in the medium term and carry potential risks.
The scientists identified and described 13 carbon removal options with the potential for deployment in the country. The initiative investigates for the first time the CO2 removal potentials of different pathways in Germany by 2050.
Researchers point out that the potential and feasibility of these measures depend on variables, like the availability of infrastructure and resources such as land and energy, some policy changes that need to happen first to unlock their potential, etc.
“While some NSE options are already deployed today, and could potentially be expanded, most of the high-tech options would need years to over a decade to be applied at scale. Additionally, the implementation of DACCS and BECCS options depends strongly on the availability of carbon storage, which is currently constrained by laws in Germany and could be unlocked by changing the current regulations. Nevertheless, it is still important to develop these technologies further so they could be deployed in the later part of the century if needed,” explains the leader of the study Malgorzata Borchers of the Helmholtz Centre for Environmental Research.
The best carbon removal pathway that was identified in Germany is biomass combustion for combined heat and power generation with carbon capture and storage (BECCS).
Bioenergy with carbon capture and storage can also be efficient when former coal-fired plants are converted to burn wood pellets. According to estimates, each such power plant of 500 MW electric size could remove just under 3 megatons of CO2 per year.
However, using woody biomass on a large scale is likely to significantly increase the overall demand for biomass which will bring the need to import biomass from outside of Germany. That is likely to have negative environmental effects on forest ecosystems abroad and cause additional CO2 emissions.
Direct air capture with permanent storage is also estimated to have potential, however, the renewable energy demand to power the technology might be a constraint in Germany. According to the research, the energy needed for a direct air capture system would be comparable to the annual energy demand of 720 000 German households.
Out of natural sink enhancement options like the rewetting of peatlands, and the afforestation of croplands, enhanced rock weathering is considered to have the highest removal potential per area.
If carbonate and silicate minerals are spread in powdered form on land like on agricultural soils to remove CO2, Germany could remove up to 5.82 million tons of CO2 each year. However, “there is a substantial energy demand associated with this CDR option from extraction to crushing and grinding of silicate rocks. Additionally, also environmental impacts should be further investigated, as there still is a need for more conclusive results,” warns one of the researchers Daniela Thrän.
The final findings from the research outline that the carbon removal potential needed for Germany is from 3 to 18 gigatons CO2 between today and 2100, depending on what the country assumes is its historical responsibility. The CO2 removal amount also depends on the actions taken in the coming years to reduce and avoid further emissions.