EGU General Assembly 2020
© Author(s) 2020. This work is distributed under
the Creative Commons Attribution 4.0 License.

Hydraulic interactions of subsurface reservoirs used for excess energy storage

Jianli Ma1,2,3, Thomas Kempka3,4, Elena Chabab3, Qi Li1,2, and Michael Kühn3,4
Jianli Ma et al.
  • 1State Key Laboratory of Geomechanics and Geotechnical Engineering, Institute of Rock and Soil Mechanics, Chinese Academy of Sciences, Wuhan,China
  • 2University of Chinese Academy of Sciences, Beijing, China
  • 3GFZ German Research Centre for Geosciences, Fluid Systems Modelling, Potsdam, Germany
  • 4University of Potsdam, Institute of Geosciences, Potsdam, Germany

Excess electricity produced from renewables can be converted into CH4 by consuming CO2 and H2 by means of the Power-to-Gas (PtG) technology [1]. Previous work indicates that subsurface storage of CO2 and CH4 can meet the projected energy storage requirements [1] [2]. However, gas mixing occurs if both gases are stored in the same reservoir [3], and energy is lost if CH4 is used as cushion gas when both gases are separately stored in different reservoirs [2]. Therefore, an innovative approach to overcome the limitation of aforementioned storage schemes is introduced in this study. For that purpose, the focus is on a double reservoir setting in one anticline system as it is commonly found in, e.g., the Northern German Basin. Here, the confining layer and preexisting or artificial hydraulic connections between the two reservoirs enable the operator to reduce energy losses and avoid gas mixing. We have elaborated a numerical multiphase flow model including the wellbore systems and reservoirs to study the fluid flow and beneficiary effects of pressure interaction between both reservoirs. Based on the geological and operational data of our regional showcase in Germany [4] [5], the energy storage efficiency is quantified, and the potential benefits of the proposed storage scheme are evaluated. It shows that the production of CH4 increases by 68% over twenty years of injection and production. Furthermore, the factors that affect storage efficiency are analyzed to provide information for the optimization of PtG-based subsurface energy storage systems. The simulation can be applied to different geological systems and for parameter sensitivity studies to reduce energy losses and improve storage efficiency.



Keywords: Power-to-Gas; Subsurface gas storage; Carbon dioxide; Methane


[1] Kühn M, Nakaten N, Streibel M, Kempka T. CO2 Geological storage and utilization for a carbon neutral “Power-to-gas-to-power” cycle to even out fluctuations of renewable energy provision. Energy Procedia. 2014; 63:8044-9.

[2] Ma J, Li Q, Kühn M, Nakaten N. Power-to-gas based subsurface energy storage: A review. Renewable and Sustainable Energy Reviews. 2018; 97:478-96.

[3] Ma J, Li Q, Kempka T, Kühn M. Hydromechanical response and impact of gas mixing behavior in subsurface CH4 storage with CO2-based cushion gas. Energy & Fuels, 2019; 33 (7), 6527-6541

[4] Streibel M, Nakaten N, Kempka T, Kühn M. Analysis of an integrated carbon cycle for storage of renewables. Energy Procedia 40 (2013): 202-211.

[5] Kühn M, Streibel M, Nakaten N, Kempka T. Integrated underground gas storage of CO2 and CH4 to decarbonise the “power-to-gas-to-gas-to-power” technology. Energy Procedia 59 (2014): 9-15.

How to cite: Ma, J., Kempka, T., Chabab, E., Li, Q., and Kühn, M.: Hydraulic interactions of subsurface reservoirs used for excess energy storage, EGU General Assembly 2020, Online, 4–8 May 2020, EGU2020-5656,, 2020