Graduate School of Frontier Sciences

2003 Fiscal Year Final Research Report Summary

• Project/Area Number: 14350525
• Research Category: Grant-in-Aid for Scientific Research (B)
• Allocation Type: Single-year Grants
• Section: 一般
• Research Field: 海洋工学
• Research Institution: The University of Tokyo
• Principal Investigator: KAGEMOTO Hiroshi The University of Tokyo, Graduate School of Frontier Sciences, Professor, 大学院・新領域創成科学研究科, 教授 (40214275)
• Co-Investigator(Kenkyū-buntansha): KINOSHITA Tsuguki The University of Tokyo, Graduate School of Frontier Sciences, Research Associate, 大学院・新領域創成科学研究科, 助手 (10313008) ; AKUTSU Yoshiaki The University of Tokyo, Graduate School of Frontier Sciences, Associate Professor, 大学院・新領域創成科学研究科, 助教授 (30175814)
• Project Period (FY): 2002 – 2003
• Keywords: offshore wind farm / floating type / generation cost / natural energy / Mega-float

Research Abstract

Among various natural energy resources, wind energy is now considered as the best candidate together with solar energy. In Japan power generation by use of wind energy has been rapidly introduced for the last few years, although the total amount of power produced from wind energy is still far less than that in Europe. Since there is little land suitable for wind power generation in Japan, offshore wind power generation is now attracting attention. Particularly, it is considered that floating type offshore wind farms may be suitable for Japan, because, in most of the coastal area around Japan, the water depth is quite large even in the close vicinity of the coast.
In this research, the following subjects related to the feasibility of a floating offshore wind farm were investigated.
(1)Detailed cost analysis associated with the construction & installation of a floating offshore wind farm.
(2)Aerodynamic interaction effects among the wind power generators deployed in a floating wind farm.
(3) The sensitivity of the wind-power generation cost to various relevant parameters associated with a floating offshore wind farm.
As the result of the study, the following things have been clarified.
(1)Among the construction & installation cost of a floating wind farm, it turned out that those associated with a mooring system was not as high as it used to be considered. Therefore, it can be said that the wind-power generation cost due to a floating offshore wind farm is affected little by the water depth of the installation site.
(2)Deploying a single point mooring system for the station keeping of a floating structure, and thus enabling the floating structure rotate automatically by the wind force so as the wind-power generators mounted on the floating structure are always kept in the position directly opposite to the wind direction without any yaw control of the wind turbines, it has been clarified that the distance between two adjacent wind-power generators could be made much narrower than that of conventional land-based wind farm.
(3) Among various parameters that could affect the power-generation cost of a floating offshore wind farm, together with the wind speed and the construction & installation cost of a floating structure, the distance from the wind farm to the coast has turned out to affect the cost significantly.