Wind turbines are springing up all across the globe as Governments harvest one of the cleanest renewable energies, the wind. The majority of wind turbines are the traditional three-bladed turbines, and while they may be getting larger, and more efficient, there’s a limit to the efficiency achievable with a bladed wind turbine. It’s known as Betz’ Law and says that there is a limit to how much kinetic energy a (bladed)wind turbine can capture. Right now, most turbines can capture about 30 percent to 40 percent.
Some people claim that the bladed wind turbines cause damage to birds and bats, and don’t like the noise they generate. So would a solution to these perceived issues, and to break the Betz-barrier, be a bladeless wind turbine? Saphon think so. It’s a company set up by a Tunisian Hassine Labaied, who was inspired by the sails of ancient Carthaginian ships and his Punic heritage:
During the Era of the Carthagian Empire (814-146 BC), “Baal Saphon” was known as the divinity of wind. The wind had a strategic importance during that period as the dominance of Carthage over the western Mediterranean Sea was made possible thanks to the power of its maritime wind-powered fleet. Carthaginian dominance over large parts of the Mediterranean Sea was perceived as such a threat to Rome that three Punic Wars fought between the two mighty empires.
While the bladeless wind turbine has not yet been used commercially, it’s design and the attraction of greater efficiency and silent operation, may well see its adoption. How does it work?
The blades are replaced by a sail-shaped body, and there is no hub or gearbox. The wind is being harnessed by a sail, which follows a non-rotational back and forth to and fro motion. This allows the conversion of the majority of the kinetic energy into mechanical energy (using pistons). This is converted to a hydraulic pressure that could either be stored (in hydraulic accumulator) or instantly converted to electricity via a hydraulic motor and a generator. This can produce an energy efficiency of 60-70%, busting Betz, Law.
Prototypes have been built and the company is seeking a manufacturing partner to develop the technology, and hopefully make it commercially available within the next two years. There is a lot of interest in the innovation; Hassine spoke at TEDGlobal 2012’s stage on June 27, 2012 at Edinburgh, Scotland, and the company won the 2012 KPMG energy innovation award.
The video below gives a history of the development of this bladeless turbine technology: The Saphonian Bladeless Wind Turbine