Evaluating the impact of battery energy storage systems capacity on the performance of coordinated control of elements in ubiquitous power networks

Abstract

Within a carbon constrained world, the proportion of generation from nonconventional renewable energy sources in the generation mix of power systems, is expected to increase substantially. The generation from renewable sources, connected to power networks mostly at distribution level, will change the traditional power flow patterns and produce adverse power fluctuations due to its random nature. Although battery energy storage systems (BESS) can be employed to reduce power fluctuations, economic constraints imposed by the high cost of them justifies, under certain conditions, converting only a portion of available renewable energy to electricity and allowing the balance to go waste[1,2], an undesirable proposition from environmental standpoint. In this back drop, a strategy, based on the coordinated control of system elements, requiring lower BESS capacity and capable of reducing renewable energy waste, to control power fluctuations is presented and its performances under different BESS capacities and operating conditions were studied and reported in this paper. Numerical simulation carried out revealed the presence of a performance saturation linked to increasing BESS capacity. Reaching the saturation at BESS capacities, MW and MWhr, much smaller than power and energy associated with fluctuating generation, demonstrates the ability of proposed algorithm to control power fluctuations efficiently. The saturation effect further suggests that the accurate estimation of capacity requirement is necessary to obtain better cost performances from BESSs.