Deutsche Version  ACT
Overarching Themes
BMBF
Analysis 9.1.2017

Possible uses of the subsurface
© Sebastian Bauer

Determining the potential of the substructure

In the ANGUS+ project, scientists examine the potential for energy storage in the geological subsurface. In addition to the storage options for natural and synthetic methane, hydrogen and compressed air in caverns and porous formations, the storage of heat in the shallow subsurface is investigated.

Project status Project completed
Type of storage Mass and heat storage
Research objective Storage material
Project duration July 2012 until December 2016

The ANGUS+ project aims at developing first concepts of subsurface spatial planning schemes with regard to energy storage in the geological subsurface. The project work focusses on the storage of hydrogen, compressed air and methane in salt caverns and porous formations as well as on heat storage in the shallow subsurface. Assessing the potentials and risks of geological energy storage sites requires an adequate system and process understanding. The ANGUS+ project therefore develops realistic - however synthetic - scenarios of energy storage in the geological subsurface which are parameterised, numerically simulated and subsequently interpreted with regard to risk analysis and impact prediction. Experimental studies support the parameterisation of thermal soil properties, geochemical processes and reactions induced by temperature changes and gas leakages. Open source numerical simulators are developed further to be applied for the scenario simulation. Based on the analyses of simulated scenarios, monitoring concepts are derived and a first methodology for large scale subsurface spatial planning is devised.

Project status of ANGUS+

Laboratory experiments were conducted to investigate the geochemical implications of subsurface energy storage, its thermal impact on the mobility of trace elements and pollutants as well as the temporal behaviour of microbiological communities affected by gas leakages. Further experimental set-ups were designed and applied to obtain first results on measured mechanical parameters of rocks and soils exposed to thermal and mechanical stresses.

Parameters for the characterisation of the geological subsurface were quantified and assembled in a database, ready for application in the scenario analyses. A web-based spatial information system was developed and is currently being equipped with scientific contents.
For the development of numerical models, the OpenGeoSys code was parallelised, an extension for the simulation of multiphase-multicomponent systems was completed and verified and is now available for scenario simulations. A more precise representation of storage gas properties and the interaction of storage gas with pore fluids was implemented. Furthermore, geochemical modules were adapted to simulate geochemical processes induced by temperature changes. Within the development of geophysical monitoring methods, codes for the seismic inversion and for the forward computation of seismic wave fields were extended, parallelized and verified, which enables the simulation of realistic sites and scenarios.

First scenario simulations and impact analyses were carried out for realistic scenarios of hydrogen storage in porous formations, for simplified scenarios of gas storage in salt caverns and for scenarios of gas and fluid leakages in near-surface aquifers. The detectability of gas and fluid leakages by means of different geophysical methods was tested and quantitatively assessed. Moreover, first realistic scenarios of heat storage in the deeper subsurface were evaluated. Based on scenario simulations of cyclic heat storage, impact studies were performed with respect to interactions between heat storage applications and contaminated groundwater. The definition of complex scenarios of near-surface heat storage is in preparation.

Project context

Starting point for the ANGUS+ project is the necessity to implement subsurface planning in order to assign priority areas for specific types of use and to prevent conflicts of use. Concepts to guide the subsurface planning procedure are required. The ANGUS+ project aims at providing first steps towards such concepts by investigating specific types of subsurface use though numerical scenario analysis on realistically defined settings. Hitherto unknown geomechanical and geochemical parameters and processes are investigated experimentally.
Participants of the ANGUS+ project are therefore with their respective expertise: the Institute of Geosciences at Kiel University, the Institute of Geography at Kiel University, the Helmholtz-Centre for Environmental Research (UFZ) in Leipzig, the German Research Centre for Geosciences (GFZ) in Potsdam and the Chair of Foundation Engineering, Soil and Rock Mechanics at Ruhr-University Bochum.

Research focus

The research approach of the ANGUS+ project is based on the assessment of storage options in the geological subsurface through numerical scenario simulations, which are subsequently evaluated with respect to environmental impacts and site competition. For this aim, potential sites have to be parameterised and numerical simulation tools have to be developed further in order to account for the governing physical and chemical processes. Analysing and interpreting the results of individual model runs for a synthetic site allows the evaluation of the respective storage option.

Sub-projects

The project activities are subdivided into the four sub-projects Parameterization, Model Development, Scenario Analysis and Subsurface Spatial Planning. The sub-project Parameterization develops the required process parameters for the investigated storage options for heat, compressed air, methane and hydrogen either from literature or by own measurements. This also includes a selection of suitable storage formations.
In the sub-project Model Development tools for the numerical simulation of the governing thermal, hydraulic, mechanical and geochemical processes are developed, validated and applied to the storage options for heat and mass considered.
By combining the parameterisation and the process simulation tools, scenarios of subsurface use can be defined and numerically implemented within the sub-project Scenario Analysis. The scenario analyses are then evaluated by criteria for subsurface use and options for action are developed within the sub-project Subsurface Spatial Planning.

Website and recommended reading

Project website: angusplus.de/en

Bauer, S., Beyer, C., Dethlefsen, F., Dietrich, P., Duttmann, R., Ebert, M., Feeser, V., Görke, U., Köber, R., Kolditz, O., Rabbel, W., Schanz, T., Schäfer, D., Würdemann, H., Dahmke, A. (2013). Impacts of the use of the geological subsurface for energy storage: an investigation concept. Environmental Earth Sciences, 70(8), 3935–3943, doi:10.1007/s12665-013-2883-0. Available at the follow link.