Floating offshore wind turbine demonstration project at Goto Islands, Japan

Offshore wind energy resources in Japanese EEZ (Exclusive Economic Zone) are now considered to be huge. In order to utilize the huge amount of energy located in relatively deep water areas, Ministry of the Environment, Japan has kicked-off the demonstration project on floating offshore wind turbine (FOWT). The project will continue for six years beginning from 2010fy to 2015fy. In the project, two FOWTs have been installed. The first FOWT mounts a 100kW wind turbine of downwind type, and the length dimensions are almost half of the second FOWT (so called as 1/2 scale model). The second FOWT mounts a 2MW wind turbine of downwind type, and called as a full scale model. The FOWTs consist of PC-steel hybrid spar (which is cost-effective) and are moored by three mooring chains. The half scale model was installed at the site on 11 June 2012 as the first grid-connected FOWT in Japan. The half scale model was attacked by very severe typhoon Sanba (1216), the greatest tropical typhoon in 2012 in the world. The behavior during the typhoon attack, including the measured environmental data and the FOWT responses is introduced. The installation of the full scale model has also successfully been made. The installation at the site completed on 18 October 2013; as the first multi-megawatt FOWT in Japan. The installation procedures and current status are also presented.