Reliability and Cost-Benefit Analysis of the Battery Energy Storage System

Abstract: The battery energy storage system (BESS) is crucial for the energy transition and decarbonisation of the energy sector. However, reliability assessment and capital cost challenges can hinder their widespread deployment. Reliability and cost-benefit analysis help address these challenges and assess BESS adoption's feasibility and viability, which is the aim of this project. A BESS contains various components such as battery packs, inverters, a DC/DC converter, a Battery Thermal Management System (BTMS), electrical protection devices, a transformer, and an Energy Management System (EMS). All these fundamental components must be considered to obtain a complete reliability prediction. Most previous studies focused on the reliability analysis of individual components, but few consider all the abovementioned components in collective reliability analysis. In this thesis, each component is mathematically modelled to estimate failure rates and then used to predict the reliability of the overall BESS system. The model accuracy is verified by comparing the computed reliability indices with the values from standards/references, showing that the proposed reliability prediction methods provide reasonable outcomes. Different scenarios to enhance BESS reliability through component redundancy are explored in this project. It is proved that applying component redundancy can boost the overall BESS reliability at the price of an increased capital cost. However, the enhancement in reliability and lifespan due to component redundancy can also curtail maintenance costs. A cost-benefit analysis assesses each scenario's profitability, considering manufacturers' and owners' perspectives. It helps determine the optimal balance between reliability and profitability. Redundancy applied to components with higher failure rates and lower costs improves the reliability and profitability of the BESS. The finding highlights the importance of strategic component selection for enhancing BESS reliability. Careful reliability and cost analysis should be performed simultaneously to find the most optimised BESS scenario.