Tubercle Blade Design

For those naysayers who doubt that Cape Wind can produce the equivalent of 75 percent of the Cape’s electricity, I have to agree that that figure is not exact. Actually, Cape Wind could provide the equivalent of 93 percent of the Cape’s electricity. That figure is not Jim Gordon’s–he is much too modest for that. It is mine. The latest research and facts bear that out.

The idea for a different turbine blade took root on Cape Cod years ago. Dr. Frank Fish, a biology professor at West Chester University in Pennsylvania, was looking at the bumps on the leading edge of the flippers on a humpback whale sculpture here on the Cape and wondered why they were there. Recognizing that there was a reason and that nature is rarely wrong, the question simmered for years, and then he decided to run some tests.

The result is a collaboration between Dr. Fish, and Dr. Paul Jacobs and Thomas McDonald, both of Technology Development Associates (TDA) of Rhode Island, to design a radical wind turbine blade that has proven, in actual performance tests, to increase electrical power generation by up to 25 percent over existing blade designs.

Historically, all blade designs have been streamlined, presumably to minimize drag and maximize efficiency. It was curious, therefore, why nature had endowed humpback whale flippers with leading edge bumps, or tubercles, with which to glide smoothly through the water. These bumps seemed counter-intuitive.

Preliminary laboratory tests comparing conventional blades with bumpy leading edge, or tubercle technology, blades showed promising results. The tubercle technology blades demonstrated a reduction in drag, higher efficiency, less noise and less blade vibration. This design showed the potential to significantly improve both the performance and economic viability, in dollars per kilowatt-hour, of wind-generated electrical power.

The next step was an in situ test, which was conducted by the Wind Energy Institute of Canada on full-size tubercle technology blades fabricated by the aptly named Whalepower Corporation of Toronto. The tests were conducted on an actual tubercle technology wind turbine, running alongside conventional wind turbines, on a bluff overlooking the Atlantic Ocean on Prince Edward Island.

The results were obtained from a year of testing, with winds ranging from dead calm to gale warning. The mean wind speeds of 5 to 7 meters/second pretty much span the mean wind speeds for Cape Wind’s Nantucket Sound wind farm.

Newly released results show that the radical leading edge turbine blade alone increases electrical energy output by a staggering amount of 22 to 24 percent. Those naysayers of Cape Wind’s claim of generating 75 percent of the electricity for Cape Cod were right. Using tubercle technology blades, it could now be closer to 93 percent.

This increase comes without taller towers, without bigger turbines, in fact without any change whatsoever in existing moving parts. It can be achieved merely by using the radical new blades or retrofitting existing blades with a tubercle leading edge.

With the Cape Wind farm permitting process now in the final stages, it is possible that we will have the pleasure of being among the first to see these radical tubercle blade designs running right off our shores.

And as unconventional as they may seem, they will effectively serve to remind us what we all learned in kindergarten: that nature is seldom wrong.

By Solon Economou, a frequent Op Ed Page contributor to The Providence Journal and a former Cape Cod Times columnist. Solon is a retired professional engineer and military officer, former physics teacher and training developer. He’s been writing professionally for over 20 years. Solon’s opinions are strictly his own, so if you don’t agree with them, don’t blame anybody else.
[relatedposts]