This work investigates the feasibility of using parabolic trough solar field to increase the enthalpy from geothermal wells' flow in order to increase the steam tons; in addition, it is possible to prevent silica deposition in the geothermal process. The high levels of irradiance in Northwestern Mexico make it possible to integrate a solar-geothermal hybrid system that uses two energy resources to provide steam for the geothermal cycle, like the Cerro Prieto geothermal field. The plant consists of a geothermal well, a parabolic trough solar field in series, flash separator, steam turbine and condenser. Well "408" of Cerro Prieto IV has enthalpy of 1566 kJ/kg and its quality must be increased by 10 points, which requires a Delta h of 194.4 kJ/kg. Under these considerations the parabolic troughs area required will be 9250 m(2), with a flow of 92.4 tons per hour (25.67 kg/s). The solar field orientation is a N-S parabolic trough concentrator. The silica content in the Cerro Prieto geothermal brine causes problems for scaling at the power facility, so scale controls must be considered. (c) 2006 Elsevier Ltd. All rights reserved.