HEATSTORE: Preliminary Design of a High Temperature Aquifer Thermal Energy Storage (HT-ATES) System in Geneva Based on TH Simulations

Abstract

Advancing the integration of Underground Thermal Energy Storage (UTES) systems with more traditional energy networks while addressing relevant technical and economic aspects is one of the aims of the European HEATSTORE project with several pilot sites in different countries. Understanding how UTES improves the efficiency of energy use and fits in an otherwise complex system of supply and demand may not be assessed properly without, among other factors, a detailed consideration of the subsurface physics at work. At the Geneva HEATSTORE pilot site, seasonal storage of up to 50 [GWh/yr] from a waste-to-energy plant into a High Temperature Aquifer Thermal Energy Storage system (HT-ATES) is planned. The Geneva site is arguably the geologically most complex within HEATSTORE as the potential HT-ATES formations are intersected by thrust and strike-slip faults and at least some parts of them display artesian conditions. In our paper, we developed different operational scenarios that investigate if and how hot water can be stored and produced without significant losses, followed by a numerical analysis to assess HT-ATES options within this complex geological situation. Our simulations are based on a detailed geologic model developed at the University of Geneva and assume a non-mechanically-deforming porous medium subjected to slightly compressible single phase porous media flow with conductive and advective heat transfer. The approach was then used to perform a sensitivity study, while investigating different physical phenomena and their impact on system efficiency.