Many islands face problems in regard to sustainable development, both environmentally and economically. Due to geographical isolation, resources like food, goods and energy are imported from the outside. Focusing on local energy use may help islands to identify sustainable strategies and solutions. Islands in transition towards using more renewable energy sources are part of the project “Cradle to Cradle Islands”, funded by the EU Interreg IVB North Sea Region Programme. Energy systems on islands are diverse and linked to each specific location. Opportunities for the development of sustainable energy solutions are often inhibited by institutional, organisational or habitual problems. It is therefore essential to examine islands individually in their context; both in regard to energy use and available resources. This can be used to assess possible energy savings and unused renewable energy sources, and visualise their interaction, the consequences for the environment, as well as the effect on insular economy. Even though islands face different problems, experiences from other islands can be used as inspiration for others. In this paper a straightforward tool for examining insular energy systems is presented. The tool is currently being applied to five different islands in the North Sea Region. The application of the model to identify the possibilities for each island can be used to improve the regional development in these areas.