Lightweight, flexible, and sporting multiple rotors, Selsam's Superturbines could greatly increase the amount of power wind generators can produce. Image copyright Selsam.

Super Wind Turbines
Tech Level: 11

Traditional wind turbines, while very innovative machines today, have a number of potential shortcomings. They rely on very large and cumbersome blades, many bigger than the wings of jumbo jets, as well as large complex gearboxes and slip rings to turn and steer their power-producing turbines.

Selsam, a leading company in windpower design, would like to supplant more traditional wind turbines with a smaller, simpler, cheaper, and more efficient innovation that they call the Selsam Superturbine.

The Supertubine is built for efficiency. Any component that does not contribute directly to the generation of power has either been eliminated or minimalized as much as possible. At its heart is a very long, flexible drive shaft, mounted on a housing with a versatile universal joint and designed to bend and twist at multiple angles to shift along with prevailing winds. Selsam compares it to the human spine, which can bend and twist forward, backward, and from side to side, but does not damage the nerves whithin. Similarly, the Superturbine shaft can do the same without damage.

The device is equipped with multiple small rotors along its shaft. Just how many depends on its length and design; most versions are depicted as having between six or eight rotors, but as many as a dozen or more could be fitted onto larger ones. They all rotate in synchronicity, with the exhaust of the upper rotors helping to drive the ones below it. As explained by Selsam officials: "Like a flock of geese, each rotor favorably affects the next in line. Like a set of louvres, the tilted rotors pull in fresh wind from above, deflecting their wakes downward to insure fresh wind for succeeding rotors and, like a stack of kites, to add overall lift which helps support the driveshaft against gravity and downwind thrust forces. The rotors act as gyroscopes or spinning tops, stabilizing the driveshaft where they are attached."

Selsam's seven-foot-diameter rotor prototypes have produced 6000 watts in 32.5 mph winds, six times more than similarly sized single-rotor wind turbines. If the concept can be scaled up successfully, the use of Superturbines could mean a tremendous jump in the amount of energy wind farms could produce.

The amount of energy could be increased even more by adding a dirigible anchored to the upper end of the turbine's spine. Thus anchored, the entire shaft can freely rotate, adding its own motion to the rotors and allowing even greater power generation. The blimp itself could be covered over with solar cells, so that every small component of the system is producing at least some power to feed into the grid.

While these devices can be deployed on land, Selsam has emphasized much more of their potential use in offshore windfarms. Moored by tethers to the sea bottom, the shaft's fulcrum would be at or very near the water surface, allowing the turbine to still tilt and twist with the wind as needed. During severe storms, it has been suggested that the Superturbine could be filled with water and "laid down" onto the water surface or below it to save the device from potential damage. Of course, this would preclude it being attached to a dirigible. The Superturbines, which are smaller and thinner than other wind turbines, would also have less visual impact on shorelines, which has been a sticking point for some windfarm locations.

Selsam also maintains that its Superturbines would be easier to transport and set up at offshore locations than traditional wind generators.

There may be some disadvantages to this system. The first is in gearing it up for full production scale and power generation. The universal joint for its fulcrum and the flexible drive shaft have proven themselves in smaller test models, but whether they will do equally well with full-scale turbines will have to be seen.

Also, because these devices move and sway with the wind, they could be potential hazards to ships, boats, and wildlife who wander too close, especially in unpredictable conditions. While sinking a ship with one is unlikely, they could still cause potential damage.

The additional cost and work of laying down subsea powerlines would also have to be taken into account with creating a Superturbine windfarm.

An artist's conception of a freighter passing close by a future offshore Superturbine farm. Image copyright Selsam.


Article added 4/20/11