A new index for techno‐economical comparison of storage technologies considering effect of self‐discharge

Abstract

AbstractThis paper presents an improved levellized cost of storage (ILCOS) index for comparing various storage technologies. The ILCOS is a modified index based on the conventional levellized cost of storage (LCOS) that includes the effect of daily self‐discharge. This index calculates the total cost of discharged energy for a storage system over its lifetime. Comparing the conventional LCOS and the proposed ILCOS metrics indicates that the ILCOS is a more accurate index for the economic analysis of storage technologies. Also, this paper introduces an algorithm by using the ILCOS index for selecting the optimum storage technology in any individual application. The algorithm inputs are the needed discharge time, the required stand‐by time, and the technical and economical characteristics of storage systems; the output is the optimum storage technology. Based on the discharge time, this algorithm investigates the storage technology in three categories: short‐duration, medium‐duration, and long‐duration applications. Any storage system that has the minimum ILCOS is the economically winning technology. Given the characteristics of the existing storage technologies, the case study shows that for long‐duration applications, the pumped hydroelectric storage (PHS) is the best option. Also, vanadium redox flow battery (VRFB) and lead‐acid (PbA) batteries are the most economic storages for medium‐duration applications.