A methodology for optimum sizing of different components (i.e., rotor diameter, electrical generator rating, and battery capacity) of a standalone wind-battery system is proposed in this paper. On the basis of time series simulation of the system performance along with different design constraints, the entire set of feasible design options, also known as the design space, has been identified on a rotor diameter vs. rated power diagram. The design space of a standalone wind-battery system identifies the entire envelope within which a feasible system may be designed. The optimum configuration of the standalone system is identified on the basis of minimum cost of energy (US$/kWh). It is observed that the cost of energy is sensitive to the magnitude of average demand and the wind regime. Sensitivity of the capital cost on the minimum cost of energy is also studied. (C) 2009 Elsevier Ltd. All rights reserved.