Battery energy storage system (BESS) has been applied extensively to provide grid services such as frequency regulation, voltage support, energy arbitrage, etc. Advanced control and optimization algorithms are implemented to meet operational requirements and to preserve battery lifetime. While fundamental research has improved the understanding of. ••Battery energy storage systems provide multifarious applications in the power grid.••BESS synergizes widely with energy production, consumption & storage components.••An up-to-date overview of BESS grid services is provided for the last 10 years.••Indicators are proposed to describe long-term battery grid service usage patterns.••Battery energy storage system (BESS)BESS grid serviceBESS allocation and integrationUsage pattern and duty profile analysisFrequency regulationBattery applications in power systemAcronymsABESS Aggregated battery energy storage systemaFRR Automatic frequency restoration reserveAGC Automatic generation controlBESS Battery energy storage systemC-rate Current rateDBESS Dual battery energy storage systemDFFR Dynamic firm frequency responseDOD Depth of dischargeDTR Dynamic thermal ratingE Energy (unit: watt hour)EFR Enhanced frequency responseEMS Energy management systemENTSO-E European Network of Transmission System Operators for ElectricityE-rate Energy rateESO Electricity system operatorESS Energy storage systemEV Electric vehicleEVCS Electric vehicle charging stationFCR Frequency containment reserveFERC Federal Energy Regulatory CommissionFRR Frequency restoration reserveHESS Hybrid energy storage systemHEV Hybrid electric vehicleIESS Integrated energy storage systemIRR Internal return rateKPI Key performance indicatorLCOE Levelized cost of electricityMBESS Mobile battery energy storage systemMESS Multi energy storage systemmFRR Manual frequency restoration reserveP Power (unit: watt)P2X Power to XPFR Primary frequency controlPV PhotovoltaicQ Capacity (unit: ampere hour)RR Replacement reserveRTP Real-time pricingSBESS Standalone battery energy storage systemSOC State of chargeSOE State of energySOH State of healthTG Tidal ge. Battery energy storage systems (BESSs) have become increasingly crucial in the modern power system due to temporal imbalances between electricity supply and demand. The power system consists of a growing number of distributed and intermittent power resources, such as photovoltaic (PV) and wind energy, as well as bidirectional power components like electric vehicles (EVs). BESS grid services, also known as use cases or applications, involve using batteries in power systems for various purposes, such as frequency regulation, voltage support, black start, renewable energy smoothing, etc. As the diversity of the BESS grid services expands rapidly to fulfill the requirement of the next-generation power system and to capture the emerging business opportunities, application and integration are among the biggest concerns for the technical and economic performance of BESS projects. Therefore, it is imperative to give an overview of the recent development of BESS in the power system.Existing literature reviews of energy storage point to various topics, such as technologies, projects, regulations, cost-benefit assessment, etc. [2,3]. The operating principles and performance characteristics of different energy storage technologies are the common topics that most of the literature covered. For instance, Ramakrishnan et al. review the different forms of energy storage an.