Germany's wind energy association Bundesverband Windenergie (BWE) says it plans to take action to ensure wind farm operators can commission outside engineers to carry out complete maintenance on wind turbines, instead of being forced to use the supplier of the technology. It wants to establish a voluntary standard whereby turbine manufacturers provide customers with the full technical details of their machines. BWE's plans have been sparked by complaints by some German wind station operators about the maintenance practices used by Vestas of Denmark (Windpower Monthly, February 2005). Earlier this year, Vestas declined to grant access to key documentation that BWE says is essential for outside companies to carry out maintenance work. Vestas' refusal, says BWE, was despite an agreement struck between the two parties in November for release of the information. "I am disappointed that contract signatures have been postponed," says BWE's Peter Ahmels.