The intensive usage of wind and solar power in the energy system leads to a growing demand for energy storage. The currently available storage technologies are expensive (batteries), have a limited development potential (hydropower) or a low power-to-power efficiency (electrolysis).
The energy is stored as thermal energy in a packed bed of natural rock. Air is used as heat transfer fluid for the charging and discharging process. The conversion of electrical energy in thermal energy is done with a electric heater and a conventional steam cycle is used to regenerate electricity. For the pilot plant with an electric storage capacity of 30 MWh and a discharge power of 1,5 MW an efficiency of 25% is aimed for. Advantages of the technology are low costs, high development potential and low environmental effects.
At the TUHH CFD Simulation is used for the detailed analysis of the pressure drop and heat transfer inside the packed bed. System simulation is used to assess the dynamics of the overall storage system and to evaluate the application options in the energy system.