Ocean power is a dark horse in the race for the future of energy--few people know much about it yet, but I predict it will be huge. I also love biomimicry, so I was delighted to discover BioPower Systems Pty. Ltd., a new company using biomimetic designs to generate power from the ocean. They have two main designs--the BioWAVE, which imitates kelp fronds, and the BioSTREAM, which imitates shark or tuna tails.
Both designs are meant to oscillate back and forth in ocean currents rather than rotating like a turbine, and they use a proprietary drivetrain to convert that low-speed high-torque oscillation into high-speed low-torque rotation of a permanent magnet motor. (No doubt a gearbox and a mechanical rectifier.) Oscillating instead of rotating makes them much less dangerous to sea creatures; the only possibility of harm to fish and other creatures is them getting smacked by a device, which is unlikely, since the waves that push the devices will also be pushing the fish in the same direction. Even the base that holds these devices to the ocean floor is biologically inspired in its design--rather than having a single beefy piling, it has many small "roots" bolting it to the seabed. This way installing the system is easier and cheaper--it "does not require large specialised vessels or drill rigs due to the small gauge of each bolt."
BioPower says the BioWAVE (kelp-like) generator captures the widest and deepest swath of wave energy of any device that does not require a huge rigid structure. It also rotates freely, so it automatically orients itself to the wave direction to maximize output. In storms, it can also lay itself flat on the ocean floor to avoid the extreme forces which would rip apart a rigid generator. (Or which would require a rigid generator to be massively overbuilt and more expensive.)
The BioSTREAM (tail-like) generator is basically an active weathervane, which changes its pitch to make the waves push it around. While not as big as the BioWAVE, it should be more efficient: they say "The motions, mechanisms, and caudal fin hydrofoil shapes of [shark, tuna, and mackerel] have been optimised 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". They say they are developing the system in sizes from half a megawatt to 2 MW.
At first I thought these systems would be great to adapt to wind power as well (avoiding the whole bird-killing problem, the main objection to wind power). However, both of these systems require the fluid they're in to go back and forth--they use the power of waves, not the power of ocean currents. This is a fundamentally different ballgame than wind power.
In any case, it will be exciting to see where this goes. Their ideas are still just in the lab, but the company's Dr. Timothy Finnigan says, "The company is now planning to conduct lab-scale model testing, and follow this with a full-scale ocean-based pilot program in 2008. Commercial units are expected to be available in 2009."
Testing in the lab now, their first in-ocean tests are planned for 2008, and projected release into the real world is in 2009.
