Insular power systems are a special case of infrastructure for power production due to their particular land morphology with extensive hills and ridges. For a higher renewable energy share in the power production, a dedicated design according to local constraints is required. The high wind and solar resources of such cases can be utilized with offshore wind turbines and concentrating solar power, respectively. In addition, pumped-hydro storage is a mature and suitable technology for such terrain. A case study is presented in the island of Rhodes to obtain a renewable energy penetration higher than 70%. The technical and financial requirements for this implementation support the design of this system, while the introduction of concentrating solar power enables significant energy savings during the periods of peak demand of the island. An annual RES penetration close to 80% can be achieved with the combined operation of both plants. The economic viability of the required investment can be ensured with selling prices of the produced electricity in the range of 0.20EUR /kWh.

This article aims to present the potential of energy transition in insular systems for social and economic transition and development, when planned and implemented appropriately, with the active involvement of local communities. To this end, the example of Sifnos Energy Community is examined and presented as a pilot case. It proves that energy transition, apart from its obvious energy conservation and climate necessity, can provide a strong contribution to the development of remote areas and the remedying of crucial issues, especially in insular communities, such as unemployment, low standards of living, isolation and energy supply security. Energy transition on Sifnos has been undertaken by the Sifnos Energy Community (SEC), with the target to achieve 100% energy independency through effective and rational projects. The major project is a centralized hybrid power plant consisting of a wind park and a pumped hydro storage system. It was designed to fully cover the current electricity demand and the anticipated forthcoming load due to the overall transition to e-mobility for the transportation sector on the island. Through the exploitation of the excess electricity production with the production of potable water and hydrogen, energy transition can facilitate the development of new professional activities on the island and reduce the local economy’s dependence on tourism. Additionally, a daily link to the neighboring larger Cyclades islands can be established with a hydrogen powered-passenger vessel, ensuring the secure and cheap overseas transportation connection of Sifnos throughout the whole year. The overall energy transition process is executed with the active involvement of the Sifnos citizens, ensuring wide public acceptance and the minimization of the projects’ impacts on the natural and human environment. At the same time, the anticipated benefits for the insular communities are maximized, highlighting the energy transition process on Sifnos as a new sustainable development pattern. For all this effort and the already achieved results, Sifnos has been declared as one of the six pilot islands of the European Community’s initiative “Clean Energy for EU Islands”.

Energy transition in islands constitutes a major challenge. Apart from a necessity, it can also be a great opportunity for sustainable social and economic development. Toward this direction, a new, promising movement has emerged recently in Greek islands. Straight from the roots of the insular population, development of energy communities comes as the result of increased awareness of local people, raised also by the legacy of lighthouse projects and initiatives. Kythnos, Ikaria, Sifnos, Tilos, Agios Efstratios, Crete, and Chalki, are all islands that have embraced the implementation of successful, local-scale innovation projects and/or initiatives, generating meaningful results across different energy aspects and contributing to positive social change. Our study provides an overview of the broader energy transition aspects in Greek islands, discusses the impact of the aforementioned exemplary cases, and further elaborates on the model of energy communities. According to our analysis, leveraging on the experience of lighthouse projects and initiatives, and on the dynamics of the emerging energy community movement, could lead to increased social and economic benefits for the insular populations, to broad public acceptance, and to minimum environmental impacts for the islands’ natural ecosystems.

This article proposes a mixture of actions for the development of an effective and rational energy transition plan for all sectors and for all types of onshore final energy use in Crete. Energy transition is initiated with an appropriate capacity building campaign. The plan is based on the introduction of energy saving measures and the exploitation of all the locally available energy resources (wind, solar, geothermal potential, biomass), integrated in a cluster of centralized and decentralized power plants and smart grids to produce electricity and heat and for the transition to e-mobility. The core of the energy transition in Crete will be a set of 14 wind parks and Pumped Hydro Storage systems (PHS) for electricity generation and 12 Combined Heat and Power plants, properly designed and dispersed in the insular territory. Economic analysis is executed for the proposed essential power plants on the island. Biomass, solar and geothermal potential can cover the heating demand in Crete several times. Heat can be produced with a specific cost of 0.05 EUR/kWhth from cogeneration plants fired with solid biomass and biogas. The wind parks-PHS systems exhibit payback periods of approximately 10 years with a final electricity selling price at 0.12 EUR/kWhel. The article shows that 100% energy transition in Crete constitutes a feasible target.