Image: Wagner Christian
One of wind power’s drawbacks is its variability: sometimes the breeze is weak; other times it is strong. To convert the rotation of wind turbines into electricity efficiently, however, generators require a single turning speed. Faster or slower than this “sweet spot” and efficiency falls off fast. To compensate, engineers design turbine hardware to have adjustable blade angles to shed surplus wind energy or to capture more. Wind turbines often also employ a transmission to gear the shaft speed up or down to the sweet spot. But both mechanisms add weight, complexity and cost.
ExRo Technologies in Vancouver is commercializing what should be a better idea: a generator that operates efficiently over a wide speed range. Retrofitted wind turbines could produce as much as 50 percent more power over time, CEO John McDonald states.
The device works much the same as a traditional generator, except that fast-acting electronic switches can engage individual generator coils as needed to harvest energy effectively at different wind speeds. An intelligent controller turns on only a few coils at low speed and connects more at higher velocities. “This means that the generator has many sweet spots,” says McDonald, who likens the concept to a car engine that saves fuel by shutting down cylinders when the driver demands less power.
ExRo has successfully tested a prototype generator. The company and an industrial partner expect to start side-by-side trials of turbines with and without the new generators soon and plan to commercialize their product by the end of 2009.
Note: This article was originally printed with the title, "Efficient Power in Any Wind".
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Add CommentCombine this electronic wizardry with the newer batteries that accept charge across a wide range, from minuscule currents to huge surges, but discharge normally on demand, and we have the makings of a sweet home sized system, perhaps rivaling solar cells or exceeding them in low sunlight, high wind areas in Canada for example. Given rising oil prices and not being overwhelmed by huge nuclear investments, wind power may prove to have a very important niche in the overall clean, renewable, or perpetual, if you will, energy sources and their solutions to the energy short-falls of the future.
Reply | Report Abuse | Link to thisi want wind power to implement in my country nepal as an practical can i be helped from your organization or not all the document are needed videos and all
Reply | Report Abuse | Link to thisgive us donation or technical help for the practical of the wind energy lproject in our college st xaviers maitighar ktm nepal
Reply | Report Abuse | Link to thisThis is a very innovative way of making wind power more efficient. It would be nice to have such high technologies work in developing countries that are more dependent on the very inefficient hydro electric power.
Reply | Report Abuse | Link to thisCoclAfrique
Reply | Report Abuse | Link to thisHydroelectric power plants have a "minimum" overall efficiency of 85% from the potential energy of the stored water to electricity. Wind generators cannot have an efficiency greater than 59.3% (the Betz coefficient); and the most efficient wind generators now produced reach only 85% of this limiting value, or appox. 50% overall efficiency (wind to electricity). Therefore, when you discuss replacing "inefficient" hydroelectric power with wind generation, you obviously don't know what you are talking about, because hydroelectric power plants are much more efficient than wind generators.
Hydroelectric plants are very destructive to the environment. If you've seen the Three Gorges area in China, you've seen the devastation and the displacement of millions of people to very poorly built tower blocks. There is just no way to build dams without environmental destruction... and isn't that the *point* of these alternative energy sources -- to learn from what we've done wrong in the past, and do better? If you wish to use water to provide power, there are better ways to do so: wave power, thermal gradient power... oh, and saying "you obviously don't know what you're talking about" is *rude*. If your viewpoint can't hold it's own w/o insults, perhaps you ought to research your topic better.
Reply | Report Abuse | Link to thisIT appears thixotropic would rather insult rather then learn a few facts from someone that has real knowlage.
Reply | Report Abuse | Link to thisThe article describes an interesting way of electrically loading the wind turbine generator to match the energy from the turbine blades. Energy control has always problem in wind turbine electric generation systems. I would like to see more on the specifics of this system.
Reply | Report Abuse | Link to thisThixotropic
Reply | Report Abuse | Link to thisI have seen the Three Gorges hydroelectic power plant in China. It was built because 300,0000 Chinese people were killed in floods on the Yangtze River in the 20 th century. It's ancillary benefits of power generation and navigation helped it get approval for construction.
Whether it is more destructive to the environment than the killing of 300,000 people is the question. If your father and mother were killed in one of the floods, I assume you would be in favor of the dam? Then think about other people that have had their fathers/mothers killed in the floods. The question from a countries point of view is: Do you build the dam to stop continual floods that kill thousands of your own people, or do you ignore the problem? Fortunately, from China's point of view, they decided to resettle people, build the dam, and save many future lives.
As far as my being rude, I was not being rude; I was just being accurate when I said that CocoAfrique did not know what she was talking about concerning efficiency. It's evident that he or she was dead wrong. When you state something that you know nothing about, what is rude in telling you that you are wrong, and don't know what you're talking about?
Yes, CocoAfrique was wrong about the 'efficiency' of hydro. But you didn't try to educate that person with so much as a few well-chosen links, either.
Reply | Report Abuse | Link to thisI suppose that is what I found to be rude; saying "you know nothing" and yet doing nothing to remedy that.
I'm troubled that you state that the Chinese government engaged in this (massively expensive) project because they were concerned about people dying in floods, and that the power generation was ancillary, just a bonus. This seems a dangerously naive viewpoint. If the government's concern was truly the safety of it's people, it could have done the same forcible relocations sans dam.
My intent here is not to insult the Chinese. After all, consumer goods and petrol are dirt cheap in the US, but medication or the expertise to save your life is often just "too pricey": this in a nation replete with both medication and expertise. It's about the do-re-mi, not about human lives.
You mention only seeing the power plant, and nothing of the areas of historical and archeological significance that were destroyed to build it.
Environmental devastation is forever. It affects future generations (and the planet's ability to support life of any kind) so much more than the death of 300K people ever could. Medicinal plants lost... animals and insects that turn out to be keystone species necessary to entire ecosystems... these things just cannot be replaced.
Certain Native American tribes believed that actions taken should be considered in the light of 7 generations to come, and our failure to do so now has far greater consequences, in keeping with our far greater power to effect drastic changes.
Were my own parents to be killed in such flooding, that would certainly not alter the inescapable logic of the situation.
Or, I could have just said, do you believe the precautionary principle has merit?
Reply | Report Abuse | Link to this;-*
Thixotropic
Reply | Report Abuse | Link to thisAs it is obvious we will never see eye to eye, this my last comment to you:
1. Rudeness - You say I was rude to CocoAfrique because I did not educate her when she stated a wrong opinion. I see my goal in these comment columns as one of verifying that the statements made about hydro & energy are truthful (not inaccurate), because there is so much misinformation out there, esp. about hydro projects. I don't see my goal as educating the general populous. If you don't know whether what you say is correct or not, don't say it. That's simple.
2. Three Gorges - I didn't say the Chinese government built Three Gorges "only" to save human lives; but I did say that this was one of the goals that assisted in the dam being built, in addition, to navigation benefits and electric power generation. I would like to think it was a primary goal, but as we all know, politics is complicated.
If the Chinese government had tried to relocate the people in the flood zone without construction of the dam, the number of people relocated would have exceeded 20 million due to the large flood zone of the Yangtze. So to minimize the amount of people that had to be relocated, you had to build the dam.
3. Deaths - I see saving human lives as more important than animal lives. Having said that, I am against species extinction by humans; but will trade that off against hundreds of thousands of human lives.
4. Environmental devastation - Environmental devastation may be forever, but natural events (volcanoes, earthquakes, tsunamis, etc.) also cause environmental devastation on a large scale (larger than man in most cases). Therefore, I see a trade-off against losing a few species, (plants/animals) as acceptable to save the thousands of human lives. One of these humans could be the next Einstein, who may indeed revolutionize the world, whereas the river dolphin has a very little chance of accomplishing that task.
4. Parents killed - We wouldn't be having this discussion if your parents had been killed; and there is no "inescapable" logic for this situation. The Three Gorges dam was built because it prevented flooding thereby saving hundreds of thousands of lives. It also generates 11,000 MW of"zero emission" electricity which is equivalent to 22 standard coal fired plants, and provides navigation facilities so that the poor farmers in the interior of China can export their grain at a reasonable price. These are trade-offs versus the animals, insects, archaeological ruins, etc. that were located in the area. I agree with this.
Fair enough. Hydro is your thing; and you are certainly not obligated to educate the general populace.
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