Within the Rich North Sea Programme the focus will be on the enhancement of biodiversity within OWFs at the Dutch Continental Shelf. This report is intended as a first step in the programme and forms the basis of existing knowledge of reef and biodiversity enhancement in the North Sea. It provides a framework for selecting enhancement options for different OWF locations. It will be used in future activities within the programme, that will be explored together with the offshore wind farm industry and NGOs. It forms a basis for the design of five offshore projects within the Rich North Sea Programme.