A practical method for conversion of ocean wave energy into electrical energy
The method enables practical, efficient and low cost harvesting of ocean energy. For more information please see the following figures and description.
The method is a mass – spring oscillating system consisting of one or two submerged water chambers connected via electromagnetic springs to a buoy that is floating on the ocean surface. The mass – spring system has a natural oscillating frequency that is equal to or lower than the frequency of the ocean waves. This will result in transfer of energy from the ocean waves into the mass – spring system. The energy is extracted from the system by using the electromagnetic springs to brake the relative motions between the masses. The electromagnetic springs brake as much as possible without stopping the oscillating motions and convert the braking forces into electrical energy.
The illustration above shows a power plant consisting of 4 wave energy devices where each surface buoy has a diameter of 3 m. The 4 energy devices are moored to 2 anchors on the ocean floor. Electrical cables (not shown on the drawings) may be mounted along the mooring lines to the sea floor and further to shore.
Estimated amount of produced energy from the power plant:
Wave height 1 meter with wave periode 6 sec: 26,8 kW
Wave height 1,5 meter with wave periode 6,5 sec: 65,6 kW
Wave height 2 meter with wave periode 7 sec: 126,0 kW
Wave height 2,5 meter with wave periode 7,5 sec: 210,8 kW
Wave height 3 meter with wave periode 8 sec: 324,0 kW
The illustration below show an energy plant located where the water depth is large.
Advantages of the method:
– relative low amount of materials to manufacture the power plant
– high efficiency in different wave heights
– ability to resist large wave forces due to flexible mooring of the components and as components are placed some distance below the surface where the wave forces are smaller
– the number of anchors on the ocean floor is small