AbstractHybrid energy power plants are remarkable option for the electrification of isolated areas, which commonly fulfill their energy demand by means of diesel generators. An energy combination comprising also PV or wind systems would lead to a reduction of costs and is, therefore, being gradually esteemed. In this paper, an optimal sizing approach was established based on a long-term energy analysis, to study the techno-economic feasibility of different hybrid systems proposed to electrify an isolated area located in the north of Saudi Arabia under different fuel cost scenarios. For each fuel cost scenario, the hybrid system has been designed and optimized to get a maximum renewable penetration ratio at a low cost of energy. An optimization model based on genetic algorithm is developed to determine the optimum hybrid systems. Three different systems are studied, with different diesel price, to relatively analyze the different hybrid systems and the result reveals that PV/battery/diesel with zero LPSP is the most cost-effective system for the proposed remote area. Sensitivity analysis reveals that that the hybrid systems is the most economically choice even if the solar radiation decreases to half. It also found that irrespective of the wind speed, PV/battery/diesel system is the optimal choice if the wind speed is less than about 6.75 m/s. At solar radiation and wind speed less than 1500 W/m2, 5.6 m/s, respectively, diesel only system is cost effective. According to the present results, there is a good economic prospective to shift the diesel plants to hybrid systems, with cost reduction opportunities of around 41% of the cost of energy.