Offshore wind farms are likely to be a key component of the United Kingdom’s strategy for renewable energy, and the Energy Act 2004 introduced a new legislative framework for the development of wind farms beyond the limits of territorial sea within designated renewable energy zones. The compatibility of the new arrangements with international marine and environmental obligations is analysed. Rights of navigation, the protection of the marine environment and the decommissioning of turbines at the end of their operational life all raise significant legal issues. The introduction of the Energy Act is an important development in assisting the construction and operation of offshore wind farms. But the law was passed at a time when a number of major reviews had concluded that the legislative and policy framework for the protection of the marine environment suffered severe weaknesses. It is unfortunate that the UK Government did not consider the creation of an offshore renewable energy industry as an opportunity to develop and apply the sort of new marine conservation strategies and legal frameworks being advocated as essential in this area.