Testing the Geochemical Feasibility of Subsurface Storage of Electrolytes for Use in Redox Flow Batteries

This study aims to outline the viability of aquifer and salt cavern storage for use in redox
flow batteries. A comprehensive detailing of the past literature was outlined, with a focus on
three broad topics: the feasibility of various redox couples, the composition of formation
waters in the North Sea, and the geochemical modelling that will take place utilising these
two factors. Furthermore, the mechanisms of electrolyte removal were explored, with
emphasis on unwanted microbially mediated redox reactions as well as adsorption.
Utilising the Geochemist’s Workbench program ‘React’, solubility-speciation modelling was
conducted on the effects of electrolyte injection into the North Sea subsurface, using three
of the most widely researched redox couples as well as formation water samples from a
study conducted by Warren, Smalley and Howarth (1994). A paper was then written,
outlining the steps and results collected from this modelling. It was ultimately found that, of
the electrolytes tested, none of them were viable for subsurface storage in the brines tested,
unless other measures, such as barrier gases or chemically altering the brine were
implemented.
Finally, a critical review of the paper was presented, providing a brief summary of the data
collected from the geochemical modelling, as well as outlining the significance of the
research as a whole.