Sustainable material life cycles : is wind energy really sustainable Renewable energies for example wind energy are regarded as sustainable energies. A conference at the Hanse Wissenschaftskolleg (Institute for Advanced Study HWK) in June 2012 raised the question wether this is really the case. The conference addressed all materials involved throughout a full life cycle of a wind turbine. Sessions on the most relevant issues structured the event: material flows and sustainability international developments life cycle approach logistics and rotor blades. Stimulating presentations and lively discussions characterized all sessions. With wind energy being a very young field a lot of research still needs to be done especially on all aspects of sustainability. Two areas were identified as especially relevant: offshore wind park maintenance and material efficiency. <engl.>