LCA More specifically, the nacelle has the highest incidence on moving parts impacts. This can be explained by the fact that the nacelle is the second heaviest component of the wind turbine and the most complex one in terms of composition. The analysis of mass environmental impacts concentration (Fig. 4) shows that the blades have a significant contribution compared to the tower (non-moving part). The tower accounts for about 88% of the overall component weight while the blades make up about 3% (Table 2). This contribution is due to their composition. The blades consist of approximately 55% glass fibre and 34% epoxy. The introduction of new materials will probably be studied in order to reduce the environmental impacts [2]. Fig. 2: Contribution of the main life cycle stages to the different impact categories Tab. 2: Mass percentage of the wind plant components Component Composite blades 2.94 Hub 2.07 Nacelle 6.79 Internal wiring 0.08 Towers 87.45 Electric grid components 0.16 Transformer station Fig. 3: Contribution of the main life cycle stages to impact categories where the production stage has been detailed Percentage (%) 0.51 Construction is the second most important stage of the whole life cycle (Fig. 5). More specifically, the foundations have a dominant incidence on 8 of the 9 environmental impact indicators, mainly because they are the heaviest part of the wind turbine (1,534 tons per foundation). On the other hand, the study stage impacts of the wind plant's life cycle are insignificant (0.003 to 0.033%). The component transportation stage from the plant site to the work site accounts for 0.2%-2.4% of the overall environmental impacts. Fig. 4: Contribution of the manufacture of moving and fixed components to the wind plant's impact The operation stage accounts for 5.1-7.2% of all life cycle impacts and these impacts mainly come from component replace- No90 June - July 2014 / jec composites magazine 37