An optimization model is developed to determine the most advantageous size of autonomous hybrid photovoltaic/wind turbine/fuel cell, wind turbine/fuel cell and photovoltaic/fuel cell systems for electrification of a remote area involving five homes (1 block) located in Namin, Ardabil, Iran. The model is developed based on three decision variables related to the system renewable energy components: number of storage tanks, total swept area by the rotating turbine blades and total area occupied by the set of photovoltaic panels. The former is an integer decision variable, while the latter two are continuous decision variables. All the components are modeled and an objective function is defined based on minimizing the life cycle cost and satisfying the maximum allowable loss of power supply probability. To determine optimal values of the variables that satisfy the load in the most cost-effective way, the use of simulated annealing and a combination of simulated annealing with harmony search and chaotic search is proposed. The simulation results indicate that the grid-independent hybrid photovoltaic/wind turbine/fuel cell system is the most cost-effective for supplying the block's electrical energy demands and that the simulated annealing-based harmony search algorithm yields more promising results than the other algorithms. (C) 2016 Elsevier Ltd. All rights reserved.