This study was commissioned by the International Energy Agency (lEA) accord- ing to Annex III of the Implementing Agreement for a Program of Research and Development of Wind Energy Conversion Systems . The working title of the study was: Integration of Wind Power into National Electricity Supply Sys- tems . Participants: - Federal Republic of Germany (40 070), represented by the Kernforschungsan- lage Jillich GmbH, - Japan (20 070), represented by The Japanese Delegation to DECD, - Netherlands (10 070), represented by The Stichting Energieonderzoek Centrum Nederland, - Sweden (10070), represented by The National Swedish Board for Energy Source Development, - United States of America (20 070), represented by The Department of Energy. The operating agent was the Kernforschungsanlage Jillich, Projektleitung Energieforschung (Project No. ET 4085 A). The authors wish to thank the temporary co-workers on the project L. Griebl, R. Meyer and H. Renner (programming), J. Boase (preliminary translation of parts of the study), W. Dub and H. Pape made several helpful suggestions for the revision of the preliminary version of the report. The extensive services of E. List!, the project secretary, made a significant contribution to the carrying out of this research project. For providing extensive facilities in the computing centre and project rooms, and for handling the financial side of the project, the authors express their thanks to the University of Regensburg.