Enhancing the Flexibility of Electricity Generation and Heating for Kizildere II Geothermal Power Plant by Demonstrating Heat Storage Systems

In the geothermal energy field, the main goal is to recover energy from brine, extracted several kilometers deep underground, in the form of heat to heating networks and/or producing electricity. Geothermal is currently engineered as an ""always on"" baseload supply, due to the limited flexibility to throttle the well without scaling and piping fatigue issues, and it is engineered for maximal efficiency at this output level. This energy source needs more flexibility to function as a fully reliable and controllable energy source. The EU H2020 GEOSMART project, started in June 2019 for a duration of 4 years, has the objective to optimize and demonstrate innovations to improve the flexibility of geothermal heat and power production systems. This article will focus on thermal energy storage demonstrations on the Kizildere II site in Turkey, which is one of the largest power plants in Turkey and in the world with 80 MWe of installed capacity. The main problem is to design a steam accumulator (5MWh) and a PCM storage (2MWh) adapted to the particular conditions of the brine extracted several kilometers underground containing a high proportion of non-condensable gases (mainly CO2) and highly mineralized water with a high risk of precipitation/scaling as soon as the temperature drops.