New and innovative solutions are being developed to overcome the challenges of detrimental effects that the traditional energy systems cause. This means that sustainable methods are implemented to do so, noting that when such developments are taken into consideration and are studied, this leads to a significant drop in the cost of renewable energy systems. In this work, a hybrid system consisting of a single flash steam geothermal power plant and a solar thermal system using a parabolic trough collector (PTC) is studied. Based on the available works in literature, the required design materials and modeling equations are chosen and discussed. The heat transfer fluid (HTF) as water is chosen as the working fluid for the PTC due to its low cost and high specific heat capacity. The calculations are carried out for the PTC on a specific day, time and location, and the simulations for the geothermal power plant (GPP) are carried out using System Advisor Model (SAM) software, assuming a specific increase in the temperature of the geofluid due to the additional heat transfer from the HTF of the PTC. The power plant output is 20 MW powered by four production wells. The results show that the energy production is ~15 GWh in January, which is the highest during the year due to the required energy demand for electricity consumption and district heating. Moreover, a mini review of the mathematical modeling of PTC and single flash geothermal power plant is presented.