This paper presents developments of the Wave Dragon, a large offshore wave energy converter. A prototype has been tested in a real sea environment for over 20 months. During 2005 the plant has been in harbor for a major overhaul of several of its components. The motivation for the upgrades, the laboratory testing procedure and the design and manufacture are described. The modifications are complete and the prototype is scheduled to be deployed at a higher energy site in December 2005.


The Wave Dragon is a floating offshore wave energy converter of the overtopping type. A full scale Wave Dragon designed for the North Sea would have a installed power of 4–11 MW. A 18.2 kW prototype has been tested in Nissum Bredning, a large inland waterway in Denmark since May 2003.

After this period of testing much information has been gained about the main components of the Wave Dragon, it is now to be deployed to a higher energy site within the Nissum Bredning area. Before redeployment several of the components have been upgraded, renovated and improved. The most noticeable of these is the joint between the long reflector arms and the main body. Issues with the robustness of the previous design for the joint necessitated replacing it with a ball and socket type joint. This new design has been extensively tested on a 1:51.8 scale model in the wave basin facilities at Aalborg University.

The manufacture of this joint is now complete and fully instrumented. Other upgrades include refurbishment of the low head hydro turbines and re-ballasting of the reflector arms. The Wave Dragon prototype is now ready to be redeployed.

Waves overtopping the ramp fill the reservoir with water at a higher level than the mean sea level.

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