Renewable Island Energy Systems: Challenges and Opportunities - From Feasible Scenarios to Implementable Pathways
Moderator: Prof. Pedro Cabrera
Islands face distinctive energy challenges, including dependence on imported fossil fuels, weak or isolated electricity grids, high energy costs, limited land availability and significant seasonal variations in demand. At the same time, their clearly defined system boundaries and abundant renewable resources make them valuable environments for developing and demonstrating innovative energy solutions. Achieving high shares of variable renewable energy requires more than increasing wind and solar capacity. Storage, demand-side flexibility and coordination between electricity, water, transport, heating and cooling can improve system reliability and reduce renewable curtailment. Desalination plants, pumping stations, water storage and electric mobility can provide particularly valuable flexibility in island systems. However, there is no single pathway suitable for every island. Batteries, pumped-hydroelectric storage, hydrogen, Power-to-X and interconnections present different advantages depending on system size, geography, available resources and infrastructure. Although many studies demonstrate that 100% renewable island energy systems are technically feasible, their economic viability, grid stability, territorial requirements, governance and practical implementation remain insufficiently addressed. This panel will bring together experts in energy-system planning, renewable integration, desalination, storage and sector coupling. By combining modelling experience with lessons from demonstration projects, the discussion will examine how technically feasible scenarios can be transformed into reliable, affordable and implementable transition pathways.
Islands should be among the first and most successful adopters of the energy transition. Energy costs on islands are typically high, and electricity systems have often relied heavily on expensive imported diesel fuel, creating strong economic incentives for renewable energy deployment. Even before the emergence of battery storage and advanced demand-response technologies, integrating significant shares, typically up to 20% wind and up to 10% solar generation was technically feasible. Today, with mature battery technologies and the growing flexibility offered by electrified demand, island energy systems can, from a techno-economic perspective, achieve near 100% renewable energy supply. Transport electrification offers particularly attractive opportunities for islands, where travel distances are limited and charging infrastructure requirements are relatively modest. In addition, much of the demand for industrial and residential heat can be electrified, further reducing dependence on imported fossil fuels. Yet despite these advantages, many islands have not become pioneers of the clean energy transition. The primary obstacles are often not technical or economic but institutional and socio-political. New energy sectors require local supply chains, maintenance services, skilled personnel, and innovative business models, all of which can be difficult to establish in small and geographically isolated communities. These emerging industries must also compete with entrenched interests linked to existing fossil fuel supply chains. As a result, larger islands with more diversified economies and competitive markets tend to progress faster, while smaller islands can become trapped in a transition stalemate. Overcoming this inertia often requires strong political leadership, targeted public support, or external financial assistance. At the same time, policy barriers such as regulated national electricity pricing, insufficient local market structures, and limited opportunities for community participation can prevent islands from utilizing the flexibility tools that are essential for high shares of renewable energy.
Islands serve as critical testbeds for the clean energy transition, yet their decarbonization requires strategies distinct from mainland paradigms. Due to geographical isolation, insular energy profiles are uniquely dominated by sectors that differ significantly in relative weight from mainland analyses—most notably maritime transport, which can account for nearly 50% of total energy consumption and greenhouse gas emissions, and energy-intensive water supply/desalination. Integrating high shares of Variable Renewable Energy Sources (vRES) into isolated grids creates severe stability challenges, shifting the need for flexibility onto demand-side management.
This talk will deal with evaluating the role of sector coupling and Demand Response (DR) as primary flexibility solutions through advanced energy system modeling applied to the case study of Favignana Island, Italy, assessing the integration of Power-to-Heat, Power-to-Transport (including maritime sector decarbonization), and Power-to-Water frameworks alongside technical grid stability constraints.
Results demonstrate that coupling the power grid with island-specific end-use sectors effectively absorbs non-dispatchable renewable excess, mitigates curtailment, and supports system stability. Compared to standalone electricity storage, sector coupling delivers superior carbon avoidance and economic savings while addressing the core drivers of insular emissions. Ultimately, this talk will support the statement that successful island decarbonization depends on prioritizing key local end-use sectors through tailored sector-coupling strategies rather than replicating mainland energy transition pathways.
