Virtual Energy Storage Systems: Challenges and Opportunities

Maintaining synchronism between generation and demand is becoming a tedious task with increasing penetration of renewables in the evolving power systems. Ancillary services are needed to settle these load-generation imbalances. The ancillary services requirement increasingly utilizing Energy Storage Systems (ESS) considering its quick response and high ramping capability. However, existing ESS technology faces challenges, such as high cost, unsteady charging/discharging cycles, life cycle issues, and optimal sizing. Thus, advanced mechanisms are required to cater the demand for ancillary services. Virtual Energy Storage Systems (VESS) is an innovative and economic way to replace/reduce higher ESS requirements. VESS utilizes existing network assets and Thermostatically Controlled Loads (TCLs). In recent years, the research in this area expands in multi-domains. Hence, there is a need to summarize the potential application of VESS in power systems. In this context, this paper is an attempt to summarise and develop an overarching view about the potential of VESS worldwide, the VESS technologies, the switching model of TCLs, and existing projects. Moreover, this review highlights the key factors and applications of VESS in power systems.