A whale of a tale
My Clean Break feature this week is a story about a Toronto company called WhalePower Corp. that has designed a new type of wind-turbine blade that dramatically improves turbine efficiency. What’s unique about the design is that it mimics the aerodynamic feature of a humpback whale’s flipper, which has bumps or “tubercles” along its leading edge. Scientists have found that the tubercles reduce the drag and increase the lift on the flipper, having the effect of delaying stall. Earlier studies have attempted to apply this principle to airplane wings and rudders on boats, but WhalePower is adapting it to blades for wind turbines, fans — essentially anything with a rotating blade that moves through air or fluid. The co-founders of WhalePower claim their blade captures more of the wind’s energy at lower speeds where conventional turbines tend to stall. For example, a turbine equipped with WhalePower blades could produce the same amount of electricity from 5 metre-per-second winds as a conventional turbine tends to produce with winds blowing at 8 metres per second. This means the humpback-designed turbines could allow wind farms to produce more kilowatt-hours a year, improving the business case for wind farms.
The big question is: Even if this is a superior blade design, would the industry be willing to change? Given turbine manufacturers are already having a tough time keeping up with demand, there’s not much incentive in radically changing the design of their product for the benefit of customers. And while WhalePower says it has a way to retrofit existing turbine blades, there’s the question of voiding the warranty — something most wind-farm operators are reluctant to do.
All that said, it’s a neat company that’s bound to attract further attention from investors and the media. And the approach could represent a way for a newcomer to the wind-turbine manufacturing market to distinguish itself from the competitive pack.
Tyler Hamilton is senior energy reporter and columnist for the Toronto Star, Canada's largest daily newspaper. In addition to this Clean Break blog, Tyler writes a weekly column of the same name that discusses trends, happenings and innovators in the cleantech market. This blog is a personal project started in April 2005. It is not an official blog of the newspaper. Tyler can be reached at tyler@cleanbreak.ca
May 14th, 2007 at 10:42 pm
The power in the wind is proportional to the cube of the wind speed, so if whalepowers claims were to be valid, the power in an 8 m/s wind is 4 times the power of a 5 m/s wind. This would make their claim outrageous, (400% more at 5 m/s than past designs) is that what they are saying, or do they have their flukes crossed with their flippers?
cheers
May 15th, 2007 at 2:30 am
The question is:
Have they patented it?
AND
Do whales count as prior art?
May 15th, 2007 at 4:51 am
I agree. The easiest way to get more power in low wind speed regimes is to fit a larger blade. This is why you can buy the same MW turbine with a range of blade sizes. Blades are also getting lighter, eventually I expect them to be made from carbon fibre instead of wood and glass fibre. Blade shapes are being refined but I don’t think there is much more improvement to be had there (a few percent maybe).
May 15th, 2007 at 8:03 am
Steve, from what I understand that’s exactly what they’re saying. That’s why they need independent verification, otherwise the claims are difficult to believe.
May 15th, 2007 at 3:24 pm
There is a theoretical maximum to wind to electricity conversion efficiency. I suspect current designs are well below that curve, and that the losses are much higher at lower speeds.
May 16th, 2007 at 12:51 am
I guess the view on prior art might depend upon whether you are a creationist or not… and whether the Pope, or someone else, has power of attorney.
May 17th, 2007 at 12:37 am
“Even if this is a superior blade design, would the industry be willing to change? Given turbine manufacturers are already having a tough time keeping up with demand, there’s not much incentive in radically changing the design of their product for the benefit of customers.”
There’s a lot of VC floating around looking for promising energy companies. If the product really is as good as it claims (and I’m dubious because revolutionary claims in the clean energy field are a daily occurance) then people will be glad to spot them a hundred million to get things rolling.
May 22nd, 2007 at 1:01 pm
Hi Tyler,
I thought you might appreciate a nite from WhalePower.
Steve Lapp is absolutely correct about the cube rule with respect to the power in the wind. But his interpretation of the test data is ill-considered: His error is his assumption that the efficiency of modern turbines is uniform across all wind speeds. It isn’t. Conventional low speed performance is still very poor, even for very large turbines. Small turbines are worse.
The gains from tubercle airfoils should not be guaged against maximum turbine efficiency in higher speed winds. Anybody and everybody gets power out of high speed winds. But there are very modern wind farms here in Ontario which are only producing abouy 22% of the “rated” or “nameplate” power. Good sites run about 27% max. That’s why a turbine that is rated at 2 MW actually delivers as little as a 450 kilowatt average on an annualized basis.
If you look at real power curves plotted against the Weibull distribution of actual wind speeds in a given location you’ll see that power production dives down faster than the power available in the wind at lower speeds. Wind’s Achilles heel is that power drops or stops when winds fall or fail.
There are severe limitations with conventional aerodynamics at low speed. Pitch has to be kept low to avoid damage during stall. Some of the really big turbines require such a large safety margin that they operate at maximum pitches at or below 7 degrees despite theoretical stall angles of 16 degrees or better. At low speeds and at low stall angles the lift-to-drag ratio gets less and less favorale and measured efficiencies are far below the optimum speed ,measurements which are typically used to report a turbine’s effieincy.
Our test results are a real world comparison. The stock turbine we employed gets 00.0 kW at 5 m/s while our blades boosted that to between 9.3 and 10.2 kW. The comparison Mr. Lapp proposes would interpret that to mean our turbine’s per centage improvement was infinite, which is absurd.
Simply put: WhalePower’s tubercle technology does not violate aeordynamics, just the claims of aerodynamicists who “knew” for decades that there was no per centage in making anything but a smooth knife-like leading edge. They were and are wrong: tubercles change the rules for low speed fluid flows in ways we have just begun to understand but are well documented in peer-reviewed articles in scientific journals.
The science is rock solid. Our engineering is real and effective. The old dogs are going to have to learn some new tricks. Of course they many give up what they “know” easily. Some won’t even enter the facts into their consciousness, preferring not to have to uproot and reformulate their understanding.
Finally, there is another point worth commenting on. May we encourage the various industry insiders who have ventured to comment on our business prospects without ever enquiring about our business plans to suspend too easy judgements. Our plans may be ambitious but we thinnk they are attainable. We really do plan to transform the world of wind energy but we do not expect to build and install the pieces ourselves. That’s what turbine manufacturers are for.
While we expect that adoption by the industry will be subject to the same kind of inertia as the science, we do believe we can license manufacturers world-wide and provide engineering services for their development of tubercle retrofits for any of their existing turbines as well as the tools for the development of a new generation of fully integrated tubercle blades.
We are confident that even major manufacturers will sign on and, after appropriate testing, will extend their warranties.
Thank you for your encouragement and support.
KEEP AN EYE OPUT FOR whalepower.com THE WHALE’S ABOUT TO BUST OUT OF THE GARAGE.
Stephen W. Dewar
VP Business Affairs & Acting Dir. of R&D
WhalePower Corporation
27 Tyrrel Avenue
Toronto, ON M6G 2G1
(tel) 416-651-7559 (fax) CALL FOR CONNECTION
stephen.dewar@whalepower.com
May 22nd, 2007 at 1:03 pm
While I do hope there is some truth to the increase in low wind speed efficiency from this design there is no way that the claims in this article can be accurate. In the best case scenario they have been able to increase the efficiency of the blades at 5m/s to efficiencies normally experienced at 8m/s and the media has simply misquoted them.
Since the theoretical maximum efficiency for extracting power from wind is 59% (Betz law http://www.windpower.org/en/tour/wres/betz.htm) and the efficiency of a good turbine is approximately 42% at 5m/s and peaks at about 50% at around 8m/s there is still some room for improvement (though most of this loss is in the generator). In order to obtain the same amount of energy output at 5m/s as at 8m/s (with approximately 4 times the kinetic energy) the new design would not only have to disprove Betz law but would have to operate at 164% efficiency essentially drawing energy from somewhere other than the kinetic energy of the air.
Despite this I continue to hope that their work yields some benefits as I am getting tired of the number of renewable energy “breakthroughs” which receive all kinds of attention and do little or nothing to advance the technology