抄録
This paper presents optimization of the SPAR-type floating structure for offshore wind turbine. Water depth of sea around Japan becomes steeply deeper with the distance from the coast. Different from Europe where bottom mounted wind turbines are installed in the shallow water, floating wind turbine is necessary for wind energy development in Japan. Total amount of energy expected on the sea around Japan is far larger than that of expected on land. The main challenge in developing the floating wind turbine is cost reduction. The authors have been studying and developing the SPAR-type wind turbine. This paper presents improvement and verification test of the 3-D response analysis program of the SPAR-type wind turbine first. Then optimization of the floating structure using the program is presented. Objective function is weight which is a dominant parameter of the cost of steel structure. Length of submerged column is changed and optimum configuration is selected.
From the research some conclusions were obtained, 1) accuracy of the analysis program was improved and verified through wave and wind tank experiment, 2) fin which is necessary to improve dynamic response of the wind turbine is not necessarily important for long column case, and 3) cost of floating structure was dramatically reduced by increasing the maximum allowable inclination limit.
