Initial capital cost for floating offshore wind farms is assessed considering manufacture and installation technologies. Engineering cost models for floating offshore wind farms are proposed and the cost parameters are evaluated based on the database. The baseline model is built for the floating offshore wind farm with six wind turbines in Japan. The cost reduction effect by the novel technologies of the flat panel welding method for the floater, the hybrid mooring line, the floating-to-fixed turbine installation and mooring line installation using AHTS is quantitively evaluated by using the proposed engineering cost model. It is found that CAPEX reduces 15 % comparing to the conventional technologies. The sensitivity study using the engineering cost model is conducted and the scenarios for the initial capital cost reduction in Japan are discussed.

抄録全体を表示

Renewable energy has significant output fluctuation. In areas with a small thermal power generation capacity, some wind power plants need to install storage batteries. Additionally, fluctuations in wind power generation output on remote islands are putting pressure on the control capacity of thermal power generation. This paper proposes a new wind speed prediction method using a wind generation power system with redox flow batteries. A fixed order of the autoregressive (AR) coefficient predicts the wind speed 60 minutes ahead, the AR model's predicted wind speed is added to the average value of the difference between the actual wind speed and the AR model's predicted wind speed, and the prediction wind speed curve is passed through a low-pass filter. As a result, the predicted power output of the power system was determined with high prediction accuracy by using the measured wind speed data, and frequency fluctuations were suppressed within an acceptable range.

抄録全体を表示

The life extension of a wind turbine is receiving more and more attention as many wind turbines reach their design life. The fatigue damage of an existing wind turbine under actual wind conditions is one of the useful information for the life extension decision. In this paper, an approximate expression of fatigue damage at the base of the tower is proposed for a reference turbine as a function of wind speed, turbulence intensity and wind direction. Next, the wind conditions at three locations measured by nacelle-mounted anemometers are presented. The fatigue damage at the base of the tower is then calculated for the site wind conditions and the design wind conditions for the reference turbine. The effects of the wind conditions on the fatigue damage are evaluated. The difference in fatigue damage between the site wind condition and the design wind condition is separated according to the effects of wind speed, turbulence intensity and wind direction.

抄録全体を表示