In recent years, the amount of energy produced by wind energy converters (WECs) has increased greatly, meaning that grid operators now have to focus on the power generation characteristics of WECs. In 2003,  the German grid operator E.ON provided the first guidelines that stated new requirements on the power generation characteristics of WECs. These could not be fulfilled with the existing technology over the full range. The German research institute FGH decided to establish an accredited product certification body in accordance with the European standard EN 45011; this body certifies the conformity of power generation characteristics of WECs with the guidelines of grid operators.