Name and Location
Fukushima recovery/floating offshore wind farm experimental project, Japan.

Client
A consortium comprising Marubeni Corporation (project integrator), the University of Tokyo (technical adviser), Mitsubishi Heavy Industries (MHI), Japan Marine United, Mitsui Engineering & Shipbuilding, Nippon Steel & Sumitomo Metal Corporation, Hitachi, Furukawa Electric, Shimizu and Mizuho Information & Research.

Project Description
The recovery/floating offshore wind farm experimental project aims to carry out experimentation and verification for the realisation of a sufficient number of offshore wind power generation plants to be commercialised, with floating wind turbines and a substation installed about 23 km off the Fukushima coast.

The first phase of the project, dubbed Fukushima Mirai, involved the installation of two floaters, with a 2 MW wind turbine and a substation each. The wind turbine blades are 122 m in height and 80 m in diameter. A downwind type of blade – located leeward – was adopted because wind blows mainly upward from the sea surface. A downwind type of blade will presumably increase power-generating efficiency by blowing wind upward.

In the second phase, two 7 MW wind turbines, with blade diameters of 160 m and a total height of 200 m, will be introduced. This will make it the world’s largest wind turbine.

The substation, dubbed Fukushima Kizuna, is 60 m above sea level, with a draft of 50 m, totalling 110 m in height, nearly as large as Fukushima Mirai. The wind turbine will produce 22 kV. The substation boosts the voltage to 66 kV to increase transmission efficiency and then transmits the power to an onshore substation 23 km away. In case of emergency, it shuts down all electrical current safely.

This is the first time that such operations have been conducted on a floating substation.

Value
Not stated.

Duration
Not stated.

Latest Developments
Preparatory works for the installation of the 7 MW oil-pressure drive-type wind turbine on the three-column semisub floater at Onahama port, Fukushima, are almost complete and delivery of the floater from Nagasaki to Onahama has started as part of the second phase of the project.

Construction of the nacelle for the 7 MW oil-pressure drive-type wind turbine is in progress at MHI’s Yokohama Dockyard & Machinery Works, while construction of the tower for the floating wind turbine is in progress at MHI.

Meanwhile, installation of chains, anchors and undersea cables at the testing area has been successfully completed.

The ground improvement and installation of the undersea mound at the Onahama port for mounting the wind turbine on the three-column semisub have been successfully completed.

Key Contracts and Suppliers
MHI, Yokohama Dockyard & Machinery Works (nacelle) and MHI Kobe Dockyard & Machinery Works (wind turbine tower).

On Budget and on Time?
Not stated.

Contact Details for Project Information
Marubeni Corporation, tel +81 3 3282 2111.
University of Tokyo, tel +81 3 3812 2111.
MHI, tel +81 3 6716 3111 or fax +81 3 6716 5800.
Japan Marine United, tel +65 6268 7360 or fax +65 6268 5827.
Nippon Steel & Sumitomo Metal Corporation, tel +81 3 6867 5607.
Hitachi, tel +81 3 3258 1111.
Furukawa Electric, tel +81 33286 3001.
Shimizu, tel 81 3 3561 1111.
Mizuho Information & Research, tel +81 3 3259 2185.