Work Package # 5
Work Package # 5: Enhanced storage of CO2 in aquifers: Team Leader Dieke Postma (GEUS), participants Claus Beier, Iver Jakobsen and Per Ambus (RISØ DTU), Majken Looms (IGG KU) Søren Jessen (GEUS), Eike Marie Thaysen (RISØ DTU).
Infiltrating groundwater removes a small part of the CO2 produced in the soil and stores this as dissolved carbonate in the subsurface for long periods of time. We will investigate how to enhance and optimize the uptake of CO2 in aquifers by the infiltrating groundwater as a way of capturing CO2 from the atmosphere.
Field sites will be established in a forested area and on arable land, both on soils that are free of CaCO3. The plots will be instrumented to measure the production of CO2 in the soil, CO2 exchange between soil and atmosphere, the transport of CO2 through the unsaturated zone and the uptake of CO2 into the saturated groundwater zone. Chemical interactions between dissolved CO2 and solids will be studied by monitoring changes in water composition in soil, unsaturated and saturated zones. Temporal and spatial variation in soil moisture will be measured, by high-resolution cross-borehole geophysical methods, to estimate groundwater recharge, and the transport of dissolved carbonate.
Mesocosm experiments will be carried out, in the laboratory, to screen various soil treatments for their potential to increase the production and transport of CO2 in the soil. Treatments comprise mineral addition of CaCO3, ultramafic rock or ground concrete, and the use of various plants and irrigation practices. The most promising treatments will be tested on the field plots.
Reactive transport of CO2 and water between soil and saturated groundwater zone will be modelled using the model-code developed in WP2 and the CO2 production in the soil under the various treatments will be quantified by a mass balance approach based on the main fluxes of carbon.