Electricity plays a crucial role in the well-being of humans and is a determining factor of the economic development of a country. Electricity issues have encouraged researchers to focus on improving power availability and quality along with reliability. This pursuit has increasingly raised the intention to integrate renewable energy (RE) into power systems to curb the problem of energy deficiency. However, intermittency in the sources of RE supply coupled with fluctuating changes in demand with respect to time has induced high risk in maintaining system reliability in terms of providing adequate supply to consumers. Whilst an energy storage system (ESS) is not another source of electricity, it is proven to be effective and viable in solving the aforementioned issues. Thus, this paper comprehensively reviews the development of ESS technologies and discusses the benefits and real-life applications of these technologies. The concept of reliability in power systems is also explored to provide an improved understanding of this study. Lastly, notable studies that have addressed the reliability impact of ESSs on power systems are discussed. This review paper therefore is expected to provide a critical analysis of ESS developments, as well as recognize their research gaps in terms of reliability studies in modern RE-integrated power networks.

Abstract:Research has found an extensive potential for utilizing energy storage within the power system sector to improve reliability. This study aims to provide a critical and systematic review of the reliability impacts of energy storage systems in this sector. The systematic literature review (SLR) is based on peer-reviewed papers published between 1996 and early 2018. Firstly, findings reveal that energy storage utilization in power systems is significant in improving system reliability and minimizing costs of transmission upgrades. Secondly, introduction of policies to shift from the use of fossil fuels to that of renewable energy positively affects energy storage system development. Thirdly, North America is an early pioneer of power system reliability and energy storage system studies. However, Asia has recently taken over the role, with China being the main driver. Research gaps within this field are also identified. This review can serve as basis for scholars in advancing the theoretical understanding of the reliability impacts of energy storage systems and in addressing the gaps within this field.

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Integrations of renewable energies, particularly solar and wind, are increasing worldwide due to carbon emission reduction efforts and maturing technologies that have driven down the cost of their energy productions. Due to the intermittency of these renewable sources, the battery energy storage system often coexists alongside solar/wind energy systems. Integrating these two aspects into power systems requires the consideration of reliability, social wellbeing and environmental factors, which collectively form a multi-objective optimization problem that this paper aims to solve with the non-dominated sorting genetic algorithm. The proposed method is able to find optimum solutions that are equally beneficial to all factors -Pareto front -without being heavily biased to any one of them. The proposed method is separated into two parts by first optimizing the penetration of solar/wind energy, followed by the optimization of the energy storage capacity in the second part. The fuzzy decision making method is utilized to select a preferred solution from the Pareto front based on the assignment of the membership function values to reflect operator's preferences. The proposed method was implemented on the IEEE Reliability Test System overlaid with the real sampled weather data. The proposed objectives in the optimization problem are also practical and useful for the expansion of generation systems.

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