Unlocking the Flexibility Potential of Geothermal with Reversible Organic Rankine Cycles

Abstract

A key advantage of geothermal power generation is its reliability and base-load capability. However, the future energy system requires reliable energy sources that can also respond quickly to changes in demand. Reversible Organic Rankine Cycles (ORCs), which can also operate as high-temperature heat pumps (HTHPs), enable geothermal systems to operate more flexibly. Combined with a district heating system and/or heat storage systems (e.g. ATES), reversible ORCs can react to the needs of the electricity grid and either produce electricity from the geothermal brine or consume power within the HTHP mode. Through the implementation of a storage system, the high-temperature heat produced during the HTHP operation can be used for increasing the geothermal power output at a later time. This work provides an overview of the application potential of reversible ORCs for geothermal systems and their high flexibility capability. Furthermore, first insights from a novel 20 kWel reversible ORC test rig, which is currently within the final construction phase at the Technical University of Munich, will be presented.