Abstract
Wind turbines produce electricity with hardly any emissions during operation. Most environmental impacts are associated with their manufacture. This work performs a comparative life cycle assessment (LCA) to evaluate the environmental impacts of different 3 MW power class wind turbines at a fictive onshore site in Germany. The three most frequently installed onshore turbine types are considered: geared converter with doubly-fed induction generator (DFIG), direct driven synchronous generator (DDSG) electrically excited and direct drive permanent magnet synchronous generator (DDPMSG). LCA reveals that environmental impacts are concentrated during manufacturing of fundament, tower and nacelle, which account for up to 19%, 30% and 99% of single impacts, respectively. Main drivers are the use of copper, steel and in case of DDPMSG also the rare earth permanent magnets. The DDSG shows higher impacts than the other wind turbines in 14 out of all 15 categories, due to the higher weight of its nacelle. Impacts due to operation add up to 3%.Four sensitivity analyses are conducted to estimate the effects of component replacement, recycling, origin of rare earths for permanent magnet production for DDPMSG and electricity yield. Possible recycling options show the highest improvement potential and even change turbine types ranking.