With respect to energy supply, most of the islands depend on importation, mainly from oil and its related products, and others are dependant on weak electricity grid connexions with mainland. Scarce resources are used inefficiently, supplying end-use energy and other life-supporting commodities, like power, heat, cold, transport fuel, water, waste treatment and waste water treatment. It is possible to integrate various flows and decrease the energy intensity, although the task is situation dependant and involves a large number of different systems. RenewIslands methodology for the assessment of alternative scenarios for energy and resource planning is presented here, and applied to several islands. The methodology helps in choosing energy and resource flows integration, based on the island needs, its resources, and the applicable technologies.