Here is another biomimicry for generating power from the ocean – BioSTREAM, imitating shark or tuna tails. This new tail-like generator is designed to oscillate back and forth in ocean currents, and not to rotate like a turbine.
To convert the low-speed high-torque oscillation into high-speed low-torque rotation of a permanent magnet motor the motor uses a proprietary drive-train. This oscillating, unlike the rotating method, endangers the sea creatures less — though the only possibility of the creatures being harmed is their getting smacked by a device. But, this again is unlikely, as the waves pushing the devices will also be pushing the fish in the same direction.
According to BioPower Systems Pty. Ltd. researchers,
The motions, mechanisms, and caudal fin hydrofoil shapes of [shark, tuna, and mackerel] have been optimized by natural selection and are known to be up to 90% efficient at converting body energy into propulsive force. Presumably when you reverse it to convert the propulsive force of waves to energy, the efficiency is just as good. The BioSTREAM would also self-orient to the waves, of course, and in rough seas can assume a streamlined configuration to avoid excess loading.
The system will be in sizes from half a megawatt to 2 MW.