Technical, ecological and economical assessment of welded joints for offshore wind energy plants

Wind energy plants play a decisive role for renewal energy production. Especially offshore constructions imply an engineering challenge during the design and erection process. Therefore, in this paper aspects describing the technical performance are combined with ecologic and economic assessments. For the foundation structure tubes with diameters from 219 mm up to 914 mm and three different welding methods are compared with regard to their ecologic and economic impacts. The investigations show that a precise modelling of the single production steps is necessary to generate meaningful results. For smaller diameters especially the weld seam preparation is important for the overall results, for larger diameters mainly the welding process of filler layers cause the highest environmental and economic impacts. Since existing regulations do not allow for a consistent specification of the fatigue behavior of the offshore relevant tube diameters, the Wöhler curves presented help to design wind energy foundation structures.