This study aims at development of a cost-effective, floating offshore wind turbine. The prototype model considered herein is composed of (1) 2-MW horizontal-axis wind turbine (HAWT) of downwind type, (2) steel monotower with 55-m hub height above sea level, (3) steel-prestressed concrete (PC) hybrid SPAR-type foundation with 70-m draft, and (4) catenary mooring system using anchor chains. In order to demonstrate the feasibility of the concept, an at-sea experiment using a 1/10-scale model of the prototype has been made. The demonstrative experiment includes (1) construction of the hybrid SPAR foundation using PC and steel, the same as the prototype; (2) dry-towing and installation to the at-sea site at 30-m distance from the quay of the Sasebo shipbuilding yard; (3) generating electric power using a 1 kW HAWT; and (4) removal from the site. During the at-sea experiment, wind speed, wind direction, tidal height, wave height, motion of the SPAR, tension in a mooring chain, and strains in the tower and the SPAR foundation have been measured. Motion of the SPAR has been numerically simulated and compared with the measured values, where basically good agreement is observed.

References

References
2.
Nielsen
,
F. G.
,
Hanson
,
T. D.
, and
Skaare
,
B.
,
2006
, “
Integrated Dynamic Analysis of Floating Offshore Wind Turbines
,”
Proceedings of 25th International Conference on Offshore Mechanics and Arctic Engineering
,
Hamburg, Germany
, Paper No. OMAE2006-92291.
3.
Skaare
,
B.
,
Hanson
,
T. D.
,
Nielsen
,
F. G.
,
Yttervik
,
R.
,
Hansen
,
A. M.
,
Thomsen
,
K.
, and
Larsen
,
T. J.
,
2007
, “
Integrated Dynamic Analysis of Floating Offshore Wind Turbines
,”
European Wind Energy Conference and Exhibition
, Milan,
EWEA
,
Brussels
,
May 7–10
.
4.
Roddier
,
D.
,
Cermelli
,
C.
, and
Weinstein
,
A.
,
2009
, “
Windfloat: A Floating Foundation for Offshore Wind Turbines. Part I: Design Basis and Qualification Process
,”
Proceedings of 28th International Conference on Ocean, Offshore and Arctic Engineering
,
Honolulu, HI
, Paper No. OMAE2009-79229.
5.
Cermelli
,
C.
,
Roddier
,
D.
, and
Aubault
,
A.
,
2009
, “
Windfloat: A Floating Foundation for Offshore Wind Turbines. Part II: Hydrodynamics Analysis
,”
Proceedings of 28th International Conference on Ocean, Offshore and Arctic Engineering
,
Honolulu, HI
, Paper No. OMAE2009-79231.
6.
Aubault
,
A.
,
Cermelli
,
C.
, and
Roddier
,
D.
,
2009
, “
Windfloat: A Floating Foundation for Offshore Wind Turbines. Part III: Structural Analysis
,”
Proceedings of 28th International Conference on Ocean, Offshore and Arctic Engineering
,
Honolulu, HI
, Paper No. OMAE2009-79232.
7.
Jonkman
,
J. M.
, and
Sclavounos
,
P. D.
,
2006
, “
Development of Fully Coupled Aeroelastic and Hydrodynamic Models for Offshore Wind Turbines
,”
National Renewable Energy Laboratory
,
Golden, Colorado
, Report No. NREL/CP-500-39066.
8.
Utsunomiya
,
T.
,
Nishida
,
E.
, and
Sato
,
I.
,
2009
, “
Wave Response Experiment on SPAR-Type Floating Bodies for Offshore Wind Turbine
,”
Proceedings of the 19th International Offshore and Polar Engineering Conference
,
Osaka, Japan
, Vol.
1
, pp.
378
383
.
9.
Utsunomiya
,
T.
,
Sato
,
T.
,
Matsukuma
,
H.
, and
Yago
,
K.
,
2009
, “
Experimental Validation for Motion of a Spar-Type Floating Offshore Wind Turbine Using 1/22.5 Scale Model
,”
Proceedings of 28th International Conference on Ocean, Offshore and Arctic Engineering
,
Honolulu, HI
, Paper No. OMAE2009-79695.
10.
Matsukuma
,
H.
, and
Utsunomiya
,
T.
,
2008
, “
Motion Analysis of a Floating Offshore Wind Turbine Considering Rotor-rotation
,”
IES J., Part A: Civ. Struct. Eng.
,
1
(
4
), pp.
268
279
.10.1080/19373260802401702
11.
Sarpkaya
,
T.
,
2010
,
Wave Forces on Offshore Structures
,
Cambridge University
,
Cambridge, UK
.
12.
Germanischer Lloyd
,
2005
,
Guideline for the Certification of Offshore Wind Turbines
,
2005 ed.
,
Germanischer Lloyd
,
Hamburg, Germany
.
13.
Utsunomiya
,
T.
,
Yoshida
,
S.
,
Ookubo
,
H.
,
Sato
,
I.
, and
Ishida
,
S.
,
2012
, “
Dynamic Analysis of a Floating Offshore Wind Turbine Under Extreme Environmental Conditions
,”
Proceedings of 31st International Conference on Ocean, Offshore and Arctic Engineering
,
Rio de Janeiro, Brazil
, Paper No. OMAE2012-83985.
You do not currently have access to this content.