A comprehensive review of energy security in islanded regions: Challenges, strategies, and sustainable development pathways

Islanded regions encounter unique multidimensional challenges in energy supply and security compared to conventional regions, owing to geographical isolation and their self-contained energy networks. This study employs a systematic literature review and multi-regional case analyses (e.g., Tsushima, El Hierro, Réunion, and Tenerife), integrating datasets from the International Energy Agency (IEA) with empirical regional energy statistics, to assess three critical dimensions in islanded regions: technical and economic limitations of fossil fuel dependence, exploitable potential of renewable energy (RE), and integration mechanisms for hybrid energy systems (HES). This study proposes an integrated technical pathway leveraging a Hybrid Multi-Energy Complementarity Model and smart microgrid (SMG) technologies. Results demonstrate that integrating renewables with storage technologies (e.g., lithium-ion batteries and hydrogen storage) enhances energy self-sufficiency to 70 %–90 %, reduces the levelized cost of electricity (LCOE) by 30 %–40 %, and cuts carbon emission intensity by over 80 %. Case studies reveal that El Hierro's hydro-wind hybrid system achieves 100 % renewable supply in summer, while Tsushima's solar-biomass configuration lowers electricity costs by 35 %,informing tailored policy recommendations for regions with unique insular characteristics. Policy recommendations emphasize fiscal incentives (e.g., tax credits and storage subsidies), community-driven energy governance, and cross-regional energy internet development to strengthen resilience. This research provides theoretical and empirical foundations for designing low-carbon, cost-effective, and reliable energy transition pathways for islanded regions.