## 2 Background Information  
### Wind Energy Development in Greek Islands and Local Reactions  
Besides the positive impact of wind energy on the environment due to the avoided CO\({}_{2}\) emissions and the substitution of expensive conventional diesel oil, its development has constituted a controversy in Greek islands over the past two decades among local communities, local authorities, the state, and investors. The first wind farms in the Greek islands were installed by the Public Power Utility in the 1980s. With Law 2244/1994, new opportunities for private investors came up and during the late 1990s the first private wind farms were installed in Crete, Evia, and elsewhere. Although initial doubts and objections were raised against wind turbines, mainly due to visual impact and the effect on the sensitive physiognomy of Greek islands, rich wind resources on islands together with legislative incentives led to the development of wind energy quickly reaching technical limits of carrying capacity in non-interconnected power systems. In the late 1990s, local newspapers and associations on the islands have already blamed wind turbines for lack of rain, water scarcity, effects on sexual behavior of animals, and soil erosion on the islands. At that time, the Greek Regulatory Authority for Energy (RAE) had set upper limits on the wind capacity to be installed specifically per island [1] at a maximum contribution of wind energy up to 15-20% of the annual energy needs of each island [2]. That same period saw increased debate on a scientific and political level about solutions to overcome these technical restrictions and allow further exploitation of wind energy. Initially, hydro pumped storage was intensively discussed as the most convenient techno-economically storage solution for Greek islands to deal with variable wind energy generation. Despite several applications for combined plants of wind energy with pumped storage, mainly in Crete, Lesbos, and Rhodes, only one project has been deployed so far, in Ikaria island. Historically, the lack of a land-planning legislative framework for the development of Renewable Energy Sources caused troubles for investors and local authorities during the environmental licensing procedure. It was necessary in order to protect the natural landscape of islands while allowing the development of wind energy to a desirable extent. One such effort (ministerial decision 49828/2008) filled a large gap and set the land-planning terms for the development of wind energy in islands. Power systems in the Greek islands face technical and economic challenges such as deep waters, lack of knowledge, bureaucracy, lack of financial resources, and lack of interconnections with the mainland [3; 4]. Additionally, there is a high cost of local power generation due to the use of diesel and heavy fuel oil for electricity supply and increased energy demand due to tourism. In parallel, the exploitation of abundant wind and solar potential is considered as a priority towards the achievement of the national goals to increase the use of renewable energy sources. Finally, local awareness also grows against conventional power generation due to possible negative effects on tourism. The development of large-scale renewable energy sources (RES) and an interconnected grid across several islands could lead to important economic and environmental benefits [5]. Within this nexus, several investors have proposed the development of large-scale wind energy projects in the islands, suggesting, in parallel, to undertake the cost for the development of underwater interconnection with the mainland. Improvements in cabling technology, underwater connections, and reduction of their cost, mainly thanks to the development of offshore wind energy in the Northern Europe, make those plans realistic. In this framework, today the interconnection of the islands with the mainland is more feasible than it was in the past and a strategic political priority in Greece.