Turbines with blades rotating about a horizontal axis are the most mature type of free flow turbines. Other types such as vertical axis turbines and designs using an underwater kite are less advanced. In addition to the open sea, vertical-axis turbines are also suitable for use in rivers and kite concepts can be applied at lower flow speeds, which offers additional market opportunities for free-flow turbines. The Dutch industry is working on all three variants of free-flow turbines (MET support, 2015). As horizontal-axis turbines are further in development, more information is available about this turbine type. This fact sheet generally assumes horizontal axis turbines, unless stated otherwise.
All information in the datasheets is also available in ESDL (Energy System Description Language). You can find them in the Energy Data Repository (EDR).