Renewables recorded 26.2% of global electricity generation in 2018 and expected to rise to 45% by 2040 attributed to nations commitment to reduce greenhouse gases since the signing of Paris agreement 2015. Policies friendly towards the development of renewable energy sources are developed, but the risk and safety assessment are still based on the traditional analytic and probabilistic risk-based assessment practices such as Event Tree Ana. Renewables recorded 26.2% of global electricity generation in 2018 and expected to rise to 45% by 2040 attributed to nations commitment to reduce greenhouse gases since the signing of Paris agreement 2015. Policies friendly towards the development of renewable energy sources are developed, but the risk and safety assessment are still based on the traditional analytic and probabilistic risk-based assessment practices such as Event Tree Analysis (ETA), Fault Tree Analysis (FTA), Failure Mode Effect Analysis (FMEA), Hazards Identification (HAZID), Hazards and Operability (HAZOP). These practices are viewed as own envelop of methodology whilst sharing a lot of common parameters and working principles. Analytic approach is becoming ineffective with increasingly complex energy system integrating renewables. There are on-going research proposing systemic based risk assessment approach but without incorporating advantages from analytic approach. The aim of this paper is to provide a comprehensive analysis of risk and safety assessment methodology for large scale energy storage currently practices in safety engineering today and comparing Causal Analysis based on System-Theoretic Accident Model and Process (STAMP) and Systems-Theoretic Process Analysis (STPA) with fault tree analysis, FMEA, HAZID, HAZOP. This paper demonstrated that systemic based risk assessment such Systems Theoretic Process Analysis (STPA) is suitable for complicated energy storage. ••Risk assessment scheme evaluation and improvement via Systems Theoretic Process Analysis-Hybrid (STPA-H).••Case study on grid connected PV system with Li-ion battery storage for large scale/utility services.••Hazards and mitigation measures of STPA-H are compared with existing approaches.••Comparative studies of risk assessment schemes including FTA, ETA, FMEA, HAZID, HAZOP, STPA.••HazardRenewablesSystem thinkingReliabilityETA Event Tree AnalysisFTA Fault Tree AnalysisFMEA Failure Mode Effect AnalysisHAZID Hazards IdentificationHAZOP Hazards and OperabilitySTPA Traditional safety engineering risk assessment method such as Event Tree Analysis (ETA), Fault Tree Analysis (FTA), Failure Mode Effect Analysis (FMEA), Hazards Identification (HAZID), Hazards and Operability (HAZOP) are the most popular probabilistic based risk assessment method to energy and storage system. These risk assessment techniques have long histories of successful application in conventional energy system whereby addition of components to system traditionally has limited impact to overall system and this allowed the component to be assessed independently from each other.Despite traditional safety engineering risk assessment techniques still being the most applied techniques, the increasing integration of renewable energy generation source introduces additional complexity to existing energy grid and storage system has caused difficulties for designer to consider all abnormal and normal situation to accustom for safety design into system effectively, pushed the limit of traditional safety engineering risk assessment techniques. First, renewable energy sources are introducing large numbers of dispersed microgrid with individual energy storage system that eventually needs to be integrated into main energy distribution network to reach the consumer. Second, the intermittent nature of solar and wind energy required more sophisticated microgrid design for operating in both grids connected mode and islanded mo.
