ARTS Project
With the ARTS (Aquifer Reaction to Thermal Storage) project, we plan to contribute to the development of greener and more sustainable energy sources by understanding the effects of underground energy storage on the environment, and in that way, to suggest better strategies for its implementation.
In this project, members of different research groups at Eawag investigate the aquifer (subsurface water reservoirs) response to the changes of temperature induced by the High-Temperature Borehole Thermal Energy Storage (HT-BTES) system. We can thus conclude on the environmental impacts of cyclic energy storage on the subsurface. Besides a full understanding of the local groundwater flow conditions, we focus our attention on assessing the impact of changes in temperature on the hydrogrochemistry, on the microbiology and the microbial behavior, and on the groundwater fauna composition.
This is approached through an extensive field work campaign, consisting of both continuous on-site monitoring and additional periodic sampling and post-analysis on three measurement stations. These stations have been created around three additional observation boreholes equipped for constant pumping, which have been drilled strategically upstream, in immediate vicinity, and downstream of the facility. They allow for a continuous measurement of hydraulic heads and water temperature at different depths, i.e., to cover different geological units existing in the project area. Additionally, continuous measurement of the concentration of dissolved gases is also possible through a portable mass-spectrometer (mini-RUEDI by Gasometrix), providing important insights into the process of bacterial respiration and into its changes due to temperature fluctuations. These continuous measurements are complemented by periodic sampling of water probes aimed to understand the groundwater chemical composition, including for instance the presence of tracer metals, dissolved ions, dissolved organic carbon, among others. Periodic sampling also allows determining the aquifer microbiome and its changes over time, as well as the aquifer’s environmental DNA (eDNA), which would allow the identification of other type of organisms.
The outputs from this intensive on-site monitoring and sampling will be employed for the generation and calibration of a numerical model, i.e., digital twin, that will allow a close representation of the hydro-bio-geo-chemical processes in the aquifer. It will be employed for subsequent long-term prediction of the aquifer’s behavior to future operational conditions of the HT-BTES facility, thus contributing to optimizing its operation.
