Analysis of wind turbine Gearbox's environmental impact considering its reliability

Wind turbines transform wind energy into electricity and it has a negative environmental impact during manufacturing or transportation. Gearbox is one of the most important components of wind turbine and its reliability is of great concern in industry. So this study performed a Life Cycle Assessment (LCA) to evaluate the environmental impact of wind turbine gearbox considering its reliability, with a cradle-to-grave approach. To quantify the influence of wind turbine gearbox's reliability on its environmental impact and provide a more realistic and accurate result, reliability analysis was integrated into LCA model. The reliability of gearbox determines not only the required amount of gearbox to achieve its design life but also the number of components which can be reused in next gearbox, both of which affect the environmental performance. First, the method to calculate these two parameters was described, afterwards, these two parameters would be used in the LCA model. Then, a 2 MW wind turbine gearbox with two recycling scenarios was used as the case study. The results show that the life cycle assessment of the gearbox is dominated by the manufacture process, and the reuse of components can reduce the impact around 10%. The reliability sensitivity analysis indicates that the environmental impact increases 25.25% as gearbox's reliability is reduced from 78.25% to 40.03%. Therefore, by taking reliability information into consideration when evaluating its environmental impact, a more accurate and realistic assessment result can be achieved. (C) 2018 Elsevier Ltd. All rights reserved.