Figure 10 shows efficiency of power output (from wave energy to generating power output) corresponding to significant wave period. In this figure, the peak of efficiency is around 12% that it is ranging from 6.5 sec to 8.5 sec of wave period. This range agrees with the range of wave period for the generating system operate efficiently in Figure 9.
The results of the open sea tests data analysis at this time, these are approximately similar to the values estimated by the theoretical analysis and water tank experiments before the open sea tests.
Figure 10 Efficiency of wave energy absorption (From wave energy to electric energy)
3. Multi-Purpose Utilization
To ensure effective utilization of Mighty Whale, research also is conducted technology for producing calm sea area, seawater drawing technology using compressed air produced by wave energy and hybrid power generation system combined with other renewable energy.
3.1 Technology for Producing Calm Sea Area
In the technology for producing calm sea area by Mighty Whale, it is the most remarkable energy which exists in the sea surface, and it is one of the large goals to make possible and calm ocean space of doing the vanishing wave of the wave as a failure of the safety in the marine, and initiating new industry there,etc.. Mighty Whale has the function equal to a floating breakwater. The efficiency of wave height dissipation by Mighty Whale is inferior than a breakwater which perfectly shields the wave, and the exchangeability of the sea water is not hurt, and still, it has the advantage of again, it is installable in spite of the water depth. In addition, the improvement in the efficiency of wave height dissipation is expected in comparison with the general floating breakwater, since the function that absorbs the wave energy is also combined. In the future, it is necessary to examine the arrangement and layout method in order to develop the calm sea area like Figure 11 by arranging Mighty Whale in large numbers.
Figure 11 Schematic of the future plan for producing calm sea area by Mighty Whale multi system
Plane arrangement and configuration also compared it on the case in which the distance of arrangement changed in the linear array, while the case in which linear array of Mighty Whale was done and case in which it was staggered are compared. Figure 12 shows characteristic of wave height dissipation in the behind area by the difference between arrangement and layout method of Mighty Whale 11 units. It is possible to do efficiency of wave height dissipation by the configuration group under 0.5 to near λ (wave length)/L(length of device) = 2.0 and seems to satisfy general performance of wave height dissipation. Especially, the wave period of 8 sec or less is occupational over about 85% on the wave period of the open sea tests area according to the data measured in a past(4).