EXPERIMENTAL STUDY
OF FLOATING OFFSHORE WIND FARM (FOWF) IN FUKUSHIMA

Tomofumi FUKUDA, Satsuki SUGAI, Rentaro HOSOYA, Shunsuke SATO and Shinji SUGIURA
Domestic Power Project Dept.,Marubeni Corporation
SUMMARY: Fukushima Floating Offshore Wind Farm Demonstration Project is world’s first project of offshore
wind power which consists of floating wind turbines and power sub-station. Marubeni promotes this project as aproject integrator with consortium and research 4 themes, permitting process, establish control system ofOperation & Maintenance, collaboration with fishery industry and project evaluation for futurecommercialization and expansion of offshore floating wind farm.
INTRODUCTION
Power shortage and a nuclear crisis caused by
the Great East Japan Earthquake two years ago
triggered Japan’s awareness to build renewableenergy infrastructure. Implementation of renewableenergy infrastructure and development of newtechnology are promoted by the Japanese
Government.
Fukushima Floating Offshore Wind Farm
Demonstration Project (Fukushima FORWARD) isthe experimental study sponsored by the Ministry ofEconomy, Trade and Industry since March 2012.
Marubeni promotes this project as a project
integrator and form a consortium with another 9companies and 1 university.
The purposes of this project are:
1) Redevelop Fukushima as a center of industry
with a strong focus on renewable energy andcreate new industries.
2) Create practical business scheme and deploy
large scale floating wind farms
3) Build up the experience and knowledge of theFloating Offshore Wind Farm (FOWF) andlead to the development of Japan’s new exportindustry.

Figure 1.

Project Execution Organization

CONSTRUCTION PHASE
This experimental project consists of threefloating wind turbines and one floating power

sub-station off the coast of Fukushima. The firstphase of this project started from 2012 is to install
2MW floating wind turbine, the world’s first 66kV
floating power sub-station and undersea cable. The
installation of these was successfully completed on
31st of October, and then the operation has been
started since December 2013.
In the second phase, two units of 7MW windturbines are scheduled to be installed in 2015.

Figure 2.

Plot of turbines and sub-station

FUNCTION OF MARUBENIMarubeni’s function of this experimental studyof FOWF is:1) Permitting process; trying early acquisition forpermits consulting with relevant ministry.
(There is no precedent FOWF in Japan.)2) Establish control system of Operation &Mntenance; Establish efficient control system
for future commercialization.
3) Collaboration with fishery industry; seeking forapproval and cooperation from fisheries.
4) Project evaluation; due diligence of estimatedcapacity, construction and maintenance cost.
OPERATION & MAINTENANCE
It is required for O&M plan thatmaximizes availability at least cost by the best
possible access to offshore plant, carrying out
maintenance as efficiently as possible. In order toestablish efficient control system, a comprehensive
O&M plan for FOWF is to be produced through thisexperimental study.
Data Monitoring
With the start of operation, we have started
supervisory control and data acquisition (SCADA)
monitoring at switching station. The operating dataof Generator and the image of floating system aremonitored in real time.
Access System
To improve accessibility to the turbines and thesub-station, we have been started to charter
catamaran offshore support boat as a transfer vessel
since December 2013. It provides more reliable,safer and effective access to the floater. The
measuring instruments on boat also help to evaluate
the sea condition.

Figure3.

investigate the sea condition before and after
installation of facilities. To collect as muchinformation as possible, the tests are carried out atvarious areas by different methods. The test showsthat the installation of FOWT does not affect thecatching condition so far.
Research of Fish Gathering EffectTo ensure the fish gathering effect, whichis said that fish is tend to be drawn to floater, theundersea condition around facilities is observed byROV. Materials stuck with the floater, which may
impact fish gathering, is also investigated. Seashells
are found sticking with the chains a month after
installation of facilities and some fish are found to
migrate around the chains and sit near the anchors.

The catamaran boat ‘J CAT ONE’SAFETY NAVIGATION
Prior to monitor safety navigation, acommittee has been established to settle themeasure of safety navigation during and after
installation of the facilities. Lights, foghorns andAIS have been installed. It has been also carriedout to notify to the parties concerned to keep alockout for other vessels and keep distance fromfacilities.
COLLABORATION WITH FISHERYINDUSTRY
It is vital to gain approval andcooperation to this experimental study fromfisheries. Some experimental ideas are put in action
to study the fish resource and fishing activity aroundproject site and to discuss the project with thefishing industry.
Committee and Working groups
A committee formed by the government,
Fukushima prefecture, local public entity,
representative of fishermen’s union and authorities
on the fields has been organized. As subordinates ofthe committee, working groups which consist of
local fishermen, the government and us are alsoorganized. We have been discussing about theimpact on the sea and fishery operation after
installation of facilities, the development of new
fishing methods, and other measures whichcollaborate with fishery.
Catching Test
Fish catching tests have been carried out
continuously with the cooperation of fishermen toFigure 4.

Figure 5.

Fish gathering, by ROV

Seashells sticking with chains

Sea Information
Sea information through observationequipment on floater is to be provided to fishermen.
The useful ways for fishermen to receive info isunder discussion. The information service such as
online or radio may be provided.
ACKNOWLEDGMENT
Special thanks to the consortium members; The
University of Tokyo, Mitsubishi Corporation,
Mitsubishi Heavy Industries, Ltd., Japan MarineUnited Corporation, Mitsui Engineering &Shipbuilding Co., Ltd., Nippon Steel & Sumitomo
Metal Corporation, Hitachi, Ltd., Furukawa ElectricCo., Ltd., Shimizu Corporation and Mizuho
Information & Research institute, Inc..