The generator of the wind turbine was three phase synchronous generator which is widely used for wind energy generation. The gearbox having the gear ratio of 2 was set between the generator and the blade. The rated power of the generator is 12.4[kW] and the rotational speed of it at the rated wind speed is 600[rev/min].
Fig.5. The setting place of the wind turbines
3.2.3 Wind Energy and Designed New Hybrid Electric Power Generating system
The wind energy of the wind turbines was calculated by Eq. (1), (2).
The result of calculation was as follows; the maximum value of wind energy was 2107.2[kWh/day], the average one was 964.40[kWh/day].
The designed electric power generating system was combined with the present electric power generating system, wind turbine, converter, the inverter having the capacity of 149[kVA], and transformer. The designed electric power generating system is shown in Fig.6.
The ratio of the wind energy to the electric energy consumption for two hundred and eighty days was as follows; the maximtan value of it was 33.4[%]. The average one was 12.9[%].
Fig.6. The designed electric power generating system
3.2.4 Effect of Weight and Air Resistance of Wind Turbines
The weight of the ship with the wind turbines increased by about 5[t]. The wet surface area of the ship increased by 0.004[%]. As the ratio of increase of the wet surface area was very small, the weight of the wind turbine was proved to have no effect to the brake horse power of the main propulsion engine.
The added brake horse power of the main propulsion engine by air resistance of the wind turbines was calculated by Eq, (3)-(6).
As the result of calculation, when the relative wind speed was 14.5[m/s] and the relative wind direction was from the head of the ship, the maximum value of added brake horse power was 23.0[kWh]. In case of that, the wind energy was 90.1[kWh] and the total fuel consumption decreased by 12.9[kg/h].
3.3 Reduction of Fuel Consumption and NOx and SOx Emission
The fuel consumption and NOx and SOx emission of the designed electric power generating system with those of the present electric power generating system were compared. They are shown in Table 2.
Table 2. The fuel consumption and NOx and SOx emission
In this paper, the design of new hybrid electric power generating system using diesel engine generator and wind energy generation system for a small ship and coal cargo one was presented. As a result, the amount of fuel consumption and NOx and SOx emission from these ships were proved to reduce by installing the wind energy generation system. The application of wind energy generation system to the electric power generation system of ship was shown to have the value of discuss to protect marine environment.
From now on, application of not only wind energy generation system but also photovoltaic generation system to electric power generation system of ship will be studied from the view of environmental problems at sea.
 P. Gipw, Wind Energy, John Willey & Sons, (1995)
 K, Sumi, T. Hashimoto, S. Yamamoto, and T. Hikima, "Basic Research on the Application of Wind Generation System to a Large Coal Cargo Ship", (2000), Proceeding of The Marine Engineering Society in Japan, 64, pp. 93-96.
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