Physical design space for isolated wind-battery system incorporating resource uncertainty

Abstract

The physical design space of a wind-battery system enables a system designer to understand the trade-offs between different system design variables, the physical limits of the major decision variables, and arrive at an optimum solution subject to an appropriate design objective. An improved methodology for design of isolated wind-battery systems by accounting for the uncertainty associated with wind speed is proposed in this article. Chance-constraint programming technique is used to incorporate resource uncertainty in system sizing; thereby, facilitating system design corresponding to a specified reliability requirement. It is found that the cut-in speed of the wind turbine plays a critical role in delivering desired power supply reliability. A feasible design solution is obtained only when the probabilities associated with the cut-in and the cut-off wind speeds are accounted for along with the specified system reliability requirement. All feasible combination of system variables generated through a time-series simulation are represented on a rotor diameter versus generator rating diagram with minimum battery bank size as parameter. Solutions obtained by the proposed method are validated by sequential Monte Carlo simulations. Optimum system configuration for a given reliability requirement is determined based on minimum cost of energy (US$/kWh). It is shown that wind-battery systems cannot be designed to provide power supply reliability beyond a maximum value.