A VRLA battery energy storage system for Metlakatla, Alaska

The emergence of new power electronics and improved battery technology has created renewed interest in battery energy storage systems (BESS). These new systems provide electric utilities with alternatives to conventional storage technologies, such as pumped hydro. BESS has the potential to provide substantial benefits in terms of energy management, improved voltage, spinning reserve and protection from interruptions when compared to large centralized storage. This paper describes a commercial, economically justified, application of the new BESS which is under construction in the Metlakatla Power and Light system. The paper outlines the system performance requirements which lead to consideration of BESS as an option; the economic factors which provided the justification for BESS as an economic alternative; and the overall BES system design and performance.