Hybrid Renewable Energy Systems for Islands: A Configurations-Based Review

Small- and medium-sized islands struggle to secure reliable, affordable, low-carbon electricity due to their isolation, scarce land, and reliance on imported fossil fuels. Hybrid renewable energy systems (HRESs) offer a way forward, but research has focused overwhelmingly on solar–wind configuration. This review critically examines HRES configurations for islands (solar–wind, solar–marine current, and wind–wave), assessing how they match local resources, system needs, and constraints. The dominance of solar–wind hybrids is attributed to their mature technology and low costs, but marine-inclusive options can provide advantages such as better predictability, efficient land use, and multifunctionality in certain island settings. A cross-configuration analysis is conducted to compare the technology readiness, suitability, and deployment contexts of different hybrid configurations. The review also examines island-specific hurdles, including economic pressures, geographic remoteness, land limitation, environmental factors, and social issues, as well as the role of energy storage and diesel backup during the energy transition. Findings stress context-driven choices over technology biases, fostering resilient and locally tailored pathways for island energy transitions.