Installation of a thermal energy storage site in an abandoned mine in Picardy (France). Part 1: Selection criteria and equipment of the experimental site

Abstract

As part of the new French law on energy transition, the Demosthene research project is studying the possibility of reusing old abandoned mines to store thermal energy in the Picardy region. The aim is to store the heat required for a small collective unit, which corresponds to a volume of water of 2,000 to 8,000 m 3 , depending on the temperature (from 15°C to 70°C). An inventory shows around 3,700 theoretically available sites in this region. These are mostly shallow dry mines, or mines that are partially flooded with around 1 m of water depth. Based on this water depth and an extraction ratio of 75%, the required mine area is approximately 10,000 m². From the forty sites that have a sufficient surface area, only one is naturally flooded, although statistically many others will exist that are currently not known. In order for this experimental site to be reproducible, the decision was made to select dry mines but with a sufficient area to achieve an artificial flooding device. Theoretically, this represents more than a thousand sites in Picardy. The most interesting one is the old limestone mine of Saint-Maximin, where a sealed basin can be built. Before installing an experimental underground thermal energy storage basin in this site, the thermomechanical and hydrothermal behavior was modeled. The aim was to optimize the position of the various sensors that will be used to monitor the basin, and to predict the future deformations induced on the walls by the thermal variations. A 100 m 3 basin, sealed with a liner, was built and fitted with eighteen sensors to measure temperature, humidity and strain. These sensors allow the stored water, the rock walls and the surrounding atmosphere to be monitored. This device must now operate for six months, i.e. a complete heating-cooling cycle, and its results will be analyzed.

Thermal Performance of Cemented Paste Backfill Body Considering Its Slurry Sedimentary Characteristics in Underground Backfill Stopes

“…Concerning the relatively high temperature in deep mines, they have been regarded as good geothermal reservoirs [10]. There are many studies that utilize the geothermal energy from abandoned mines around the world [11][12][13][14][15]. Owing to the higher temperature of deep underground mines, the thermal energy contained in the surrounding rocks can be absorbed by HET [16].…”

“…In China, Tangkou Coal Mine in Jining uses the recovered mine drainage to heat the mines and surrounding houses [18]. Mine galleries have been adopted for the preheating or precooling of relatively large buildings [12]. The utilization of the geothermal resources in deep mines could offset certain economic costs and supply green heat energy to communities distributed in and around the mine area, including commercial buildings and community buildings nearby, which is a rehabilitative way that effectively reduces the damage to the environment and promotes resource recycling [19].…”