After several decades of theoretical developments, desk studies, experimental wind turbines and prototype wind farms, the first large-scale commercial developments of offshore wind farms are now being built. To support and accelerate this development, the European Commission funded a project, ‘Concerted Action on Offshore Wind Energy in Europe’ (CA-OWEE), which aimed to gather, evaluate, synthesize and distribute knowledge on all aspects of offshore wind energy, including offshore technology, electrical integration, economics, environmental impacts and political aspects. The partners are from a wide range of fields and include developers, utilities, consultants, research institutes and universities. This article reports on the final conclusions of this project, with the complete report being available online at http://www.offshorewindenergy.org. Copyright © 2003 John Wiley & Sons, Ltd.