Resilience of standalone microgrids: indicators, enhancement strategies, and challenges—an integrative review

Microgrids have emerged as a promising solution for improving energy access, enhancing local energy independence, and strengthening resilience against environmental, technical, and operational disturbances. Resilience refers to the ability of a system to withstand, adapt to, and recover from disruptive events while maintaining reliable operation. Unlike grid-connected systems, standalone or islanded microgrids must operate autonomously during disturbances, making resilience a critical design and operational consideration. This paper presents an integrative review of the state-of-the-art (SOTA) strategies, indicators, and challenges associated with enhancing the resilience of standalone microgrids. Following a PRISMA-guided review methodology, the study synthesizes 60 primary studies published between 2014 and 2025, supported by 28 contextual references. Coding of the primary studies shows that 95% rely on simulation or analytical modeling, with only three reporting experimental or hardware-in-the-loop validation, which remains the principal limitation of the current evidence base. The discussion is categorized into four major areas: design and planning, control strategies, energy management, and protection systems. In addition, the review examines resilience assessment metrics and emerging cyber-physical resilience approaches for modern standalone microgrids. The paper further identifies major technical, economic, environmental, and regulatory challenges affecting the operation of resilient microgrids, including protection coordination, renewable intermittency, communication dependence, cybersecurity risks, economic limitations, and vulnerability to extreme weather events. Various resilience enhancement approaches—distributed energy resource diversification, adaptive reconfiguration, hierarchical control, predictive energy management, and the interconnection of neighboring standalone microgrids—are critically analyzed to provide a broader understanding of resilient standalone microgrid development. Finally, the review highlights important research gaps and future directions, including the need for standardized resilience metrics, integrated cyber-physical security frameworks, climate-adaptive planning models, and practical implementation strategies. Although significant progress has been achieved in microgrid modeling, control, and optimization, considerable challenges remain in bridging theoretical research with large-scale real-world deployment of resilient standalone microgrids.