5.7 Renewable energy The European Union aims to provide 20% of consumed energy from renewable sources by 2020. In Greece the development of tidal and wave renewable energy units have not received particular interest, and the majority of renewable energy applications relate to solar and wind energy sources (RAE 2012). Conditions for the installation of offshore wind farms are considered favourable in Greece since wind intensity is predictable, large areas exhibit high wind energy potential and relatively shallow waters. Existing wind farms in insular areas are located on land, apart from one small offshore wind farm constructed in Irakleia island in the Cyclades. Up until the end of 2012, no onshore wind farms have been constructed at seabird colony sites nor inshore or offshore wind farms at major seabird foraging or migration marine areas. However a significant number of applications for offshore wind farms has been submitted to the Regulatory Authority for Energy (RAE), while large numbers of proposals are planned onshore uninhabited islets, many of which host significant seabird breeding colonies. These are reported in the description of relevant marine IBA sites including potential impacts on seabird populations. Wind farms can negatively affect seabirds, both during the construction and operation stages. Improper sitting of wind farms may lead to degradation, destruction or loss of seabird breeding habitats on land or foraging and movement habitats at sea. Wind turbines may pose barriers to migration and local foraging movements, disrupt ecological continuity and increase the risk of collision causing mortality or injuries. Additionally, they may cause habitat loss and disturbance from operating turbines, ship traffic and human presence during maintenance (Exo et al. 2003; Petersen et al. 2006).
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These become especially significant in areas along migratory bottlenecks and migration routes of seabirds, such as the coastal waters of the Northeast Aegean islands through which shearwaters travel on migration to the Black Sea to overwinter or during local foraging trips, as well as the Kafireas Strait. The impacts of offshore wind farms on seabirds are usually more significant than those recorded from onshore farms on terrestrial birds since marine wind turbines are larger in height, the wind farms themselves are larger and usually birds are found in great abundance, especially when offshore wind farms are located close to breeding colonies or foraging grounds (Exo et al. 2003). Data on bird mortality is scarce, mainly due to the difficulty in recovering dead birds at sea. Existing studies have shown that collision rates are relatively low, due to avoidance which affects flying, resting and foraging behaviour of seabirds, although rates could be higher in poor visibility conditions (Desholm and Kahlert 2005). Long-term monitoring at wind farms in Denmark indicated that the majority of bird species avoided flying between the turbine rows (Desholm and Kahlert 2005; DONG Energy 2006; Petersen et al 2006). Post-construction use of the wind farm area decreased relative to the pre-construction baseline, demonstrating foraging habitat loss to wind farms. Thus, planning of offshore wind farms should take into account avian migration routes and foraging grounds in the marine environment in order to mitigate impacts to seabirds. The EU’s Environmental Impact Assessment Directive requires assessment of the cumulative effects and impacts arising from all wind farms in the surrounding area (Exo et al. 2003). Mitigation measures from onshore schemes are also applicable to offshore wind farms.