Insular electricity systems are of importance, as the security of supply, the competitiveness and the sustainability of the islands' populations depend on non- or weakly interconnected electrical systems. For this reason, they have until now been treated with a good degree of conservatism in relation to both the power generation technologies used and the regulatory framework applied. This, however, results in power generation costs significantly higher than those of the interconnected systems, whilst it is also linked with high local environmental burdens. However, developments in the fields of renewable energy systems technologies, of weather prediction models and of grids and micro-grids management allow today for a much more responsive and adaptive management of the insular systems than was possible only ten years ago. This is further enhanced by the progress made in electrical energy storage, which makes the autonomy of islands a realistic goal, and also a feasible one, especially for small and very small islands. It is against this background that the regulatory framework has also to be re-considered, in order to enable a fair valuation and charging of storage, of load curtailment and eventually of ensured supply and quality of electrical energy. All this needs to be part of the new modus operandi towards decarbonized and sustainable insular communities. (C) 2019 Elsevier Ltd. All rights reserved.