Assessment of Geothermal and Solar Hybrid Power Generation Technologies in Turkey and Its Application to Menderes Graben

The basis of this study is the widespread existence of low enthalpy geothermal resources in Turkey. The usage of low enthalpy geothermal resources in balneology, district heating and green house heating has made Turkey one of the primary consumer of geothermal energy in the world. However, the utilization of low enthalpy geothermal resources in geothermal-solar hybrid systems for electricity generation, which is the unique focus of the analysis in this work, has not received sufficient attention so far. The study thus fills the gap in the literature by defining potential sites for this type of hybrid systems based on geography specific data. The proposed method comprises the development of a solar parabolic troughs-ORC geothermal enhancement technology for superheating binary cycle fluids to higher temperatures thereby increasing their enthalpy for more feasible energy conversion. Since the hybrid technology cannot be considered in isolation from geological aspects, the proposed method assesses the distributed geothermal and solar hybrid potential of Turkey through the use of geographic information systems. After compiling a detailed inventory of geothermal data, low enthalpy geothermal resources are mapped. Considering the possibility of transmission of geothermal fluids, buffer zones are assigned. Regions that are suitable for solar power plant implementation are intersected by buffer zones. After each region is checked for its direct solar radiation value, the map addressing the potential regions suitable for this hybrid technology is obtained. The data of the selected location from GIS application is used in a mathematical model of an already existing-hybrid system, which was developed, and power output of the system is calculated. Considering the fact that the main player in Turkish electricity production market is natural gas with a 31.9% share, the annual amount of saved carbon and money is calculated when that amount of power is produced from local geothermal-solar sources rather than imported natural gas.