Low efficiency and power generation are commonly associated with low-temperature geothermal power plants and reservoirs. As a result, among geothermal resources, low-temperature reservoirs are the least used for power production. It is wished to determine how addition of solar thermal energy to low-temperature, binary-cycle geothermal power plants affects overall energy and exergy efficiencies, as well as net power production. A computational tool for assessment of such power plants is developed, where thermodynamic, economic and environmental aspects are taken into account. Model tuning with field data, sensitivity, working fluids and case study analyses are carried out.
Results show agreement between computational tool developed and field data. Direct implementation of solar thermal energy into geothermal power plants provides higher levels of net power output, although selection of working fluid plays a major role. Efficiencies, under geothermal-only conditions, are maintained the same or reduced with solar energy addition.