Assessment of geothermal power potential in the Gediz Basin, Turkey

•Geothermal power potential for the Gediz graben was estimated.•3 geothermal potential estimates for extentional region of Turkey were completed.•Temperature dependent volume method is introduced for geothermal assessment.•All graben potential not yet discovered and further investigation is suggested.•Low-to-moderate with a few high-temperature resources found in the Gediz graben.•Study reveals the need for an updated study of Turkey's geothermal power potential. By the end of 2020, the installed geothermal power capacity in Turkey reached 1643 MWe. Approximately one-fifth of the capacity of the installed power plants is located at the Gediz graben, which is geologically the second largest structure of the Menderes Massif. The Gediz graben has several geothermal surface manifestations and geothermal resources that have been discovered. When considering the structural/geological similarities between the Buyuk Menderes and the Gediz graben, both regions can be assessed as geothermal basins. The scope of this study is to estimate the geothermal power potential of the Gediz graben. To achieve this, a different stochastic approach is used rather than the conventional geothermal resource assessment. This approach involves using temperature depended volume distributions obtained from drilled wells, which lead to improved and solid results. Three hot anomalies that are identified from temperature dependent volumes are evaluated using the Monte Carlo Simulation technique. In these simulations, distribution data of other parameters are used along with data obtained from the drilled wells in the region. The power potential (MWe) values for three identified anomalies in terms of P10, P50 and P90 values are estimated to be 825, 1157 and 1524 MWe, respectively. Furthermore, additional geothermal potential discovery is predicted in the graben, provided that extensive efforts are exerted.