In the current context of increasing public awareness of the externalities of fossil fuel-based energy consumption, improvement in new technologies for energy-saving systems has become a crucial target to reduce both global warming and air pollution. Being motivated by such a critical matter, this study presents an innovative solar thermal plant based on volumetric expanders as work-producing devices coupled with Scheffler solar receivers as a thermal source. Nowadays, Scheffler receivers are well performing owing to high efficiency of the focal receiver which reduce heat losses. Simultaneously, screw expanders are volumetric machines which are able to convert thermal to mechanical power with acceptable efficiency also by expanding vapor-liquid blends at low operating pressures. The numerical model presented in this study evaluates the energetic benefits of the proposed solar power system for various operating situations. Parametric optimization of this solar power plant is then performed in a broad range of operating conditions: the optimum evaporation temperatures, together with the corresponding maximum global efficiencies, were so defined under various solar radiation intensities. The numerical results attained in this research prove that solar electricity generation systems based on screw expanders coupled with the Scheffler receivers are a promising technology.