As America’s appetite for alternative energy grows, so does the length of the backorder on many green-energy inventions. Wind power is certainly no exception – keeping up with demand can be nearly impossible. Massive, city-sized wind farms produce immense power, but the materials and energy required to produce and transport 30-story-tall monster blades can be costly and tricky.
But one California inventor believes the answer lies in thinking smaller. Doug Selsam suggests that putting several (anywhere from two to dozens) smaller rotors on the same shaft linked to the same generator could produce the same amount of power with fewer raw materials. But the physics behind the invention - called The Sky Serpent - is no cake walk. To increase efficiency, each rotor needs to catch its own wind flow, not just the wind kicked out from the next rotor up the line. To do this, Selsam needed to figure out the precision angling of the shaft in relation to the other rotors plus the optimal spacing between each rotor. If that sounds confusing and complicated, that’s because it is.
Selsam first thought of this concept during a fluid dynamics class at the University of California at Irvine. Although he never made it all the way to graduation, his interest in new wind-power designs strengthened. In the next decades, he spent countless hours gathering information on the latest technologies. In 2003, the California Energy Commission awarded him a $75,000 grant to develop a 3000-watt turbine. Turns out “lucky seven” isn’t just a superstition – it’s the magic number of blades needed to provide that amount of wattage.
Wind currently produces about 1 percent of world-wide electricity use, but countries like Denmark (where 19 percent of the country’s electricity needs are met by wind power) are leading the charge. Globally, wind power generation increased more than fivefold between 2000 and 2007. The reasons why there’s such a renewed interest in wind power are plentiful. Wind power is renewable, clean and readily available. Many jurisdictions receive some financial or other support to encourage its development. Wind power consumes no fuel for continuing operation, and has no emissions directly related to electricity production.
According to his statistics, Selsam’s invention uses just one-tenth of the blade material required to produce today’s enormous turbines. He’s even moving into the residential market; Selsam has built and sold more than 20 dual-rotor turbines to homeowners. In the not-too-distant future, Selsam envisions strings of wind rotors stretching across the sky. “The wind-turbine designs out there are a thousand years old,” he told Popular Science (who honored his invention as one of 2007’s best). “More rotors equals more power.”
