The storage of energy is one of the main challenges of energy transition, especially for the heating energy, which must be available in winter as needed. In order to apply the heat in a climate-neutral manner, seasonal energy storage systems must be developed so that the surplus energy from the summer months can be provided to the cold seasons as needed. For this purpose, large-volume storage systems must be developed in (large) cities, with which a district heating network can be supplied. Therefore, the underground aquifer storages can be recommended, and it is necessary to bring the existing uncertainties related to such storages under scientific and technical monitoring. As essential parameters for determining energy flow, temperature and flowrates at the injection and production wells should be measured and monitored. The up to date frequently encountered problems at aquifer heat storage worldwide are geochemically induced precipitation and corrosion processes. Such processes would induce clogging and leakage into the overlying and underlying system components as well. In order to expose the processes undermining the efficiency of the storages and make the sustainable system management possible, it is required to develop proper techniques and methods to monitor system-relevant parameters as well as to deploy early-warning systems. The following goals are to be achieved in detail:
- Monitoring of thermal energy balance in the subsurface
- Planning the system in a way reducing maintenance
- Optimizing the efficiency of energy usage
- Ensuring the environmental compatibility of the storages
The knowledge obtained by fulfilling the goals (1-4) will be tested in the demonstration projects in corporation with the partners. The thereby collected experience will be analyzed in an integrated manner, and provide references for other underground energy storage projects and applications.
