Fukushima Floating Offshore Wind FarmDemonstration Project（ Fukushima FORWARD ）Fukushima Floating Offshore Wind Farm Demonstration Project

Fukushima Floating Offshore Wind Farm Demonstration Project
Fukushima offshore wind consortium, which
consists of Marubeni Corporation (Project integrator),
the University of Tokyo(Technical advisor), Mitsubishi
Corporation, Mitsubishi Heavy Industries, Japan
Marine United Corporation, Mitsui Engineering &Shipbuilding, Nippon Steel & Sumitomo Metal Corporation, Ltd., Hitachi Ltd., Furukawa Electric Co., Ltd.,
Shimizu Corporation and Mizuho information &Research, is proceeding with Fukushima floatingoffshore wind farm demonstration project (Fukushima
FORWARD) funded by the Ministry of Economy,Trade and Industry.
In this project, three floating wind turbines and one
floating power sub-station will be installed off thecoast of Fukushima. The first phase of the project
consists of one 2MW floating wind turbine, the world
first 25MVA floating substation and undersea cable,
and will be completed in 2013. In the second phase
two world largest 7MW wind turbines will be installed
before 2015.
This project will establish the business-model of thefloating wind farm and contribute to future commercialprojects. The consortium members are also expected
to learn know-how of floating offshore wind farm,
which will be one of the major export industries inJapan.

The Fukushima FORWARD project believes tohelp Fukushima to become the center of new industry
which will create new employment in this region torecover from the damage of the Great East Japan
Earthquake in 2011.

Field view of FORWARD

Floating Substation

Compact Semi-sub

Advanced Spar

V-shape Semisub

Scope of FORWARD
PhaseⅠ(2011～2013)
Floating Substation

Compact Semi-Sub（2MW）

PhaseⅡ(2014～2015)
Advanced Spar
（7MW）

V-shape Semi-Sub（7MW）

Three key factors for successTechnical Challenge ／ Social Acceptance ／Design ／Test
Test ／ Optimization

Recovery of Fukushima

Cost efficiency ／ Standardization ／ Industrialization
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Vision of Fukushima Floating Offshore Wind Farm
Two decades have passed since the first bottommounted offshore wind turbine was installed inEurope and many large scale commercial projects
are in operation now. On the other hand, a few floating offshore wind turbine(FOWT) has been installed
as a pilot project in Norway and Portugal. Several
technical questions such as floater optimization andtransmission system need to be solved for future
large scale projects.
A V-Shape semi-sub floater with the world largest
7MW turbine, the world first 25MVA floating substation and the 66kV undersea cable will be implemented in Fukushima project and the economicalfeasibility will be studied.
A metocean measurement system considering thefloater motion compensation will be developed inorder to evaluate the performance and the motion ofFOWT. Furthermore, the characteristics of eachfloater and the wind turbine, and the effect of control
system on floater motion will be investigated.
In addition, the advanced steel material against
corrosion and fatigue and construction technology
under severe weather condition will be developed.
The project will not only focus on technical challenges but also on collaboration with fishery industry,
marine navigation safety and environmental assess-ment, which are needed for the future large offshore
floating wind farm. Public relations work will be
carried out so that the status and results of thisproject will be open to public.

Vision of FORWARD
Fukushima Recovery
・Wind energy industrial accumulation
・Employment creation
・Offshore wind energy introduction

Fukushima ProjectTechnical challenge

Social acceptance・Floater concept

・Marine navigation safety

・Measurement and predibtion
・Floating substation
・Advanced steel material

・Environmental assessment
・Collaboration with fishery industry
・Public relation

FORWARD member and Main role
FORWARD member

Main role

Marubeni Corporation [ Project integrator ]Feasibility study, Approval and licensing, O & M,
Collaboration with fishery industry

The University of Tokyo [ Technical adviser ]Metocean measurement and prediction Technology,
Marine navigation safety, Public relation

Mitsubishi Corporation

Coordination for grid integration, Environmental impact assessment

Mitsubishi Heavy industries, Ltd.

V-shape semi-sub(7MW)

Japan Marine United Corporation

Advanced Spar, Floating Substation

Mitsui Engineering & Shipbuilding Co., Ltd.

Compact Semi-sub(2MW)

Nippon Steel & Sumitomo Metal

Advanced steel material

Hitachi Ltd.

Floating Substation

Furukawa Electric Co., Ltd.

Large capacity undersea cable

Shimizu Corporation

Pre-survey of ocean area, Construction technology

Mizuho Information & Research institute, Inc

Documentation, Committee Operation

Pre-studies
approval

Measurement
prediction

Floatingwindturbine

Floating
substation

O&M

Envi. Assess.
navigation
Safety collab.
with fisheryDocument

Publicrelation

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Metocean Measurement and Floater Motion Prediction
A metocean measurement system is developed by considering the floater motion compensation. Wind
speed profile and wind direction are measured by anemometers on a met mast and a lider on the floater andare compared each othes. The motion of the floater is measured by using gyro, compass, accelerometer andGPS, and used for the motion compensation.
Also, in this project a dynamic analysis model of FOWT is developed. The model is improved by comparing
the model results with water tank test and measurement data at the site.
1

Metocean and floater motion measurement
Items

2

Prediction of floater motion

ScopesScopes

Items

Metoceanmeasurement

・Development of a metocean measurement system
considering the floater motion compensation.

Floater motion
measurement

・Development of accurate floater motion
measurement system by combining gyro, compass,accelerometer and GPS.

Dynamic
analysis model
Refinement of
the model

・Development of a coupled analysis model ofwind turbine, floater and mooring.
・Development of the wind turbine control model
which takes the floater motion into account.
・Improvement of the analysis model by comparing withwater tank test and on site measurements.

Measurement system on the floating substation

Water tank test

●Measurement systemmeteorology
oceanography
motionwind

cup anemometer,wind vane,thermometer,barometer, lider

casecurrent

1

○

wave

wind

motionwave

wave buoy, ADCP○

2current

accelerometer, GPS, gyro,compass

mooring stress3●Lider・Able to measurewind speed up to
200m above sea
level.
・Ceonveenient andeconomical thanconventional tower
measurement.

○○

○

wave
current

wind

Advanced spar

Water tank test

Floating Wind Turbine Technology
In the first phase of this project, minimization of floater motion, safety and power generation efficiency areattempted by using a compact semi-submersible floater with 2MW downwind wind turbine.
In the second phase, optimization and verification of the design is attempted by using V-Shapesemi-submersible floater with the world largest 7MW wind turbine. These studies will establish technologies fora future large scale offshore floating wind farm.
1

Compact semi-sub floater with 2MW down wind turbine

2V-Shape semi-sub floater with 7MW turbine

Items

Scopes

Items

Scopes

Turbine・Verification of 2MW down
wind turbine.

Turbineof・Verification
hydraulic turbine.

・Development of compact
semi-sub floater.

Floating

・Development of V-shapesemi-sub floating.

・Minimization of floater
motion and optimizationof power generation byturbine control.

Floatingofthe・Development
reductionof
floating
motion by turbine control
and O&M program.

Mooring・8 pieces catenary.

・Minimization of floater
motion by optimization ofballast

Mooring・6 pieces catenary.

7MW・Rotor diameter・Hub height・Height of the floater

80m
65m (ASL)
32m

・Rotor diameter・Hub height・Height of the floater

164m
105m (ASL)
32m

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Floating Grid Integration System
An offshore floating transformer system which is both durable and unsusceptible to motion is developed byevaluating its performance against vibration and inclination through the shaking table tests.
Furthermore, a large capacity water proof riser cable superior to fatigue is developed and optimized bymotion analysis. The goal of these studies is to establish the world first floating offshore transformer systemagainst severe metocean conditions.
1 Transmission system for floating offshore wind farmItems

2Scopes・Establishment of design criteria under motion.
・Vibration test, inclination test.

Design and test

Riser cable, cable joint and motion analysis
Items

ScopesRiser cable

・Development of water proof cable superior to fatigue
under high voltage(22/66kv) condition.
・Design and optimization of dynamic cable by cablemotion analysis.

Joint device
for riser cable

・Development of joint device between different
materials and development of anchor device.
・Design of sub system (intermediate buoy, teminalreinforcement) by motion analysis.

・Comparison of two type.
(GIS and Vacuum circuit breaker）

Verification of GIS・Periodical cut on & off of equipment and continuous
observation.

O&M

Behavior analysis of riser cable

Grid integration system

G

Inclination test

Offshore transformer

Onshore gridconnection point

buoyancy
66kV submarine
cable

Section of riser cable

Floating
offshorewindturbine

Floating substation

buoyancy

buoyancy

66kV risercable

22kV riser cable

Optimized form of joint cable by motion analysisjoint

Pre-survey and Construction Technology for Floating Offshore Wind Farm
Optimal construction method which can be conducted under severe weather and minimize the impact on fisheryenvironment is developed based on preliminary survey and estimation of meteocean condition.
Furthermore, optimal construction method for windfarm which consists of multiple floating wind turbines will beestablished.
1Pre-survey and environmental evaluation
Items

ScopesDevelopment of construction technology
Items

Nearshore ・Sounding survey.
area・Diving survey.

Scopes・Optimization of construction method, workfleet
Construction technology
and construction equipment.
for offshore
・Development of construction method minimizing
floating wind turbine
deployment area of mooring for large scale offloating offshore wind farm.

Marine survey

・Sounding, seabed surface,core sampling.

Offshorearea

2

Environmental condition
・Estimation of wind velocity and wave height.
for construction

Offshore seabed survey

Construction method of floating offshore wind turbine

Side scan sonar

Cable length（30ｍ～400ｍ）
Survey ship
Patrol ship
Transponder in waterSide scan sonar

Positioning
device in water

Multi beammeasurement
equipment

Earth layer search

Construction method
for minimizing deployment areaof mooring

SeabedEfficientinstallationof mooring

sedimentary layer
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Advanced Steel Material
The TMCP and UIT developed in Japan are applied into steel material for the world first FOWT and thewelding efficiency, corrosion resistance and fatigue for the long operation under the severe metocean conditionare verified.
These studies will achieve shortening of the construction time and reduction of the construction cost.
1 Advanced steel material for floating offshore wind turbine
Items

Advanced steel material for tower, floater and catenary

ScopesSteel forfloating wind turbine
made in Japan・Application of TMCP to floating offshore wind turbine
steel material and clarification of improvement ofwelding efficiency.
High tension steel
for offshore
wind turbine

TMCP（Thermo-mechanical Control Process）
High heat input welding to be utilized for high tension
steel among ship building and construction field andfeatured to be as high efficiency welding and easy
construction control.

・Application of UIT technology into ultrasonic blow
wave treatment and clarification.
Fatigue solution

Catenary chain

UIT（Ultrasonic Impact Treatment）:
Promising technology which improve dramaticallyfatigue feature of welding joint.

TMCP

High heat input welding

・Preheated free・Better welding efficiency

・Better weld ability

・Reduction of welding risk

・Better base material

・Better joint performance

Improvement of fatigue performance by UIT・Development of steel material for catenary superior
to durability and corrosion.
Improvement of fatigue feature by UIT（cross welding connection）

Marine Navigation Safety
For floating offshore wind turbines, collisions between ships or collisions between ships and turbines might occur. Development of a collisionrisk model is carried out and the quantitative collision risk is assessed. Actual traffic data in the coast area along Fukushima are collected. Thecollision risk assessment makes it possible to take appropriate safety measures.
If mooring is failed by severe storms or accidents, drifting floaters may collide with other wind turbines and ships. A simulation method basedon actual response of floating turbines is developed and the consequences of drifting of floating turbines is confirmed.
1

Assessment of collision risk
Items

ScopesCollision risk analysis
and risk control option

・Quantitative risk analysis for collision based on risk
model and traffic data・Adoption of appropriate risk controloption (safetymeasures)

Observation of navigation
Oceangoing vessels’ traffic

Domestic and fishing wessels’ traffic
Fishry vessel

Fishry vessel

Observation by rader

Collection oftraffic datain the coast area

2・Analysis of oceangoing vessels’ traffic by AIS data.
(past and daily data)
・Observation for domestic and fishing vessels’ traffic
by Rader.

Assessment of drifting risk
Items

ScopesView of recorded data
by Automatic identification system

Oceanographic vessel

Safety verification by drifting risk
Concurrent drifting

Drifting test

・Development of analysis method of low frequency,
Response ofwave frequency and high frequency motion ofmoored floating offshore
moored floating offshore wind turbine.
wind turbine

Drifting Collision

Analysis method ofdrifting risk offloating wind turbine

・Development of a simulator for risk analysis ofdrifting floating offshore wind turbines considering
coupled response of a floater, a wind turbine anda mooring system.
Wind, Current, Wave

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Environmental Impact Assessment
The environmental impact assessment is implemented around the sea where FOWT and seabed cable areinstalled.
The habits for seabirds, marine mammal and fish in addition to noise, scenery and radio disturbance will besurveyed and the environmental impact from the installation of the turbine and seabed cable will be clarified.
1

Survey area and item
Items

Detail (in habiting situation)
・Feedings, migrant of bird

Bird

Survey for seabird and marine mammal around the floating offshore wind turbine
7km

Survey area
aturbine cable

H：130ｍ以上

4km

b

3km
5km
3km

●

ab

3km

Marine mamma ・Whale, Dolphine●

M：30 ～ 130ｍ

・Background noise and horizontal component
in normal condition water●・Fish, prawn/crab, squid octopus●●

Fish egg
larval・Fish, egg, young fish●

●Plankton

・Zooplankton & phytoplankton●●Intertidalorganism

・Attached organism and benthic living fromseashore to 3m deep water.

●Marine plant

・Brown algae such as sea grape and Ecklonia
stolonifera.

●Macrobentos

・Benthic activity such as bivalve, univalveshee
and shell fish.

●

・Benthic activity such as sea chestnut,
sea cucumber and sand star.

●・Sediment made of seawater, earth and sand.

●Underwatersound

A：0 ～ 100ｍ

B：100 ～ 200ｍ

L：0 ～ 30ｍ

Fish

Attached
OrganismMegabenth.
OthersAround the seabed cable survey for fishery, fish egg, and plankton
fishery

fish eggplankton

Collaboration with Fishery Industry
A committee formed by the government, Fukushima prefecture, local public entity and fishermen’s union isorganized. The impact on the sea and fishery operation around the project after installation of FOWT and a new
fishing method are investigated working together with the special consultant of fishery industry.
After that, a proposal for fish gathering effect by marine farm, marine fertilization and culture raft and providing sea
information will be discussed.
1

Proposal for new fishing method
Items

ScopesMarine farm・Construction of new fishery farm by automatic feeder,sound and fishing bank using floater and mooring

Marine fertilizationand culture raft

・Cultivation of shellfish and seaweed by marine
fertilization through water pumping of deep sea
by density diffusion equipment and marine fertilizer

Fish gathering effect・Observation of fish gathering around floater by ROV

Sea information

Marine farm

Marine fertilization

・Providing of real time sea information throughobservation equipment on floater to fisherman
and disaster control center

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Marubeni Corporation
1-4-2 Otemachi, Chiyada-ku, Tokyo 100-8088

The University of Tokyo
7-3-1 Hongo, Bunkyo-ku, Tokyo 113-8656

Mitsubishi Corporation
2-3-1 Marunouchi, Chiyoda-ku, Tokyo 100-8086

Mitsubishi Heavy industries, Ltd.
2-16-5 Konan, Minato-ku, Tokyo 108-8215

Japan Marine United Corporation
5-36-7 Shiba, Minato-ku, Tokyo 108-0014

Mitsui Engineering & Shipbuilding Co., Ltd.
5-6-4 Tsukiji Chuo-ku, Tokyo 104-8439

Nippon Steel & Sumitomo Metal
2-6-1 Marunouchi, Chiyoda-ku,Tokyp 100-8071

Hitachi Ltd.
1-6-6 Marunouchi, Chiyoda-ku, Tokyo 100-8280

Furukawa Electric Co., Ltd.
2-2-3 Marunouchi, Chiyoda-ku, Tokyo 100-8322

Shimizu Corporation
2-16-1 Kyobashi, Chuo-ku, Tokyo 104-8370

Mizuho Information & Research institute, Inc
2-3 Kandanishikicho, Chiyoda-ku, Tokyo 101-8443

Contacts:
The University of Tokyo
Department of Civil Engineering
School of Engineering
Prof. Dr. Takeshi Ishihara
Manager Shigeru Taki
2-11-16 Yayoi Bunkyo Tokyo 113-8656 Japan
Tel +81-3-5841-6145 fax +81-3-5841-0609