NETPEC

Negative Emission Technologies based on Photoelectrochemical Methods – Potentials of geological disposal

Identification of geological storage areas for carbon-rich products based on atmospheric CO2 using photelectrochemical techniques (artificial photosynthesis).

Projekt NETPEC

Facts about the project

PhD project: Sarah Diekmeier +++ Duration: 01.02.2022 bis 30.09.2025 +++ Project funding: Bundesministerium für Forschung, Techoloie und Raumfahrt (BMFTR) Projektträger DLR

Click here for the official website of the NETPEC project

As part of the multidisciplinary NETPEC project, photoelectrochemical methods are being developed for efficient technologies to extract carbon dioxide from the atmosphere. The resulting carbon-rich product, whether liquid or solid, should enable safe long-term storage. This means that a much wider range of geological storage areas can be considered for long-term storage, compared to previous approaches of storing CO2 in gaseous or liquefied state directly in the underground. For this purpose, it is necessary to investigate a qualitative and quantitative study of possible storage scenarios. Based on this, an initial assessment of the geomechanical and geochemical interactions between the storage product and the geological storage areas will be carried out.

After definition of criteria for a database in which the characteristics of potential geological disposal areas can be collected qualitatively and quantitatively, the database will be used for the region of Germany first. The focus is primarily on geological areas that have already been used previously anthropogenic, such as former reservoirs, mines or opencast mines. Based on this, generalised emplacement scenarios are identified, depending on the emplacement product and the geological formations. In order to make an initial assessment of the geomechanical interactions between the emplacement products and the geological emplacement volume, geomechanical-numerical models will be applied, to investigate the interaction of the classified emplacement concepts in their geological framework with the emplacement product in a generalised way. In Addition an initial assessment of potential dissolution and transport pathways will be made based on hydrogeochemical models.

Currently, there are three possible options as a sink product resulting from the process: graphite, oxalate also in solid form, and oxalic acid which is dissolved in a solvent, in liquid form. For these three options, there are different possibilities for long-term safe final disposal or even for further use

Deposition scenarios for the options of repository products resulting from the photoelectrochemical approaches.
Deposition scenarios for the options of repository products resulting from the photoelectrochemical approaches.
  • Diekmeier, S., Reiter, K., Henk, A., & Friebe, C. (2024). Storage potentials for carbon-rich products in Germany – a database and outlook on final storage of products derived from negative emission technologies.Earth System Science Data. https://doi.org/10.5194/essd-2024-489
  • Diekmeier, S., Reiter, K., Friebe, C. (2023): Storage potentials for artificial CO2 products in Germany. EGU General Assembly 2023. https://doi.org/10.5194/egusphere-egu23-13953

Status Quo & Outlook

The qualitative and quantitative assessment of potential geological storage sites in Germany has been completed and the evaluation of possible interactions between end product options and geological storage sites is beginning.