What is Wind turbines: Definition and 37 Discussions

A wind turbine is a device that converts the wind's kinetic energy into electrical energy.
Wind turbines are manufactured in a wide range of sizes, with either horizontal or vertical axes. It is estimated that hundreds of thousands of large turbines, in installations known as wind farms, now generate over 650 gigawatts of power, with 60 GW added each year. They are an increasingly important source of intermittent renewable energy, and are used in many countries to lower energy costs and reduce reliance on fossil fuels. One study claimed that, as of 2009, wind had the "lowest relative greenhouse gas emissions, the least water consumption demands and... the most favourable social impacts" compared to photovoltaic, hydro, geothermal, coal and gas.Smaller wind turbines are used for applications such as battery charging for auxiliary power for boats or caravans, and to power traffic warning signs. Larger turbines can contribute to a domestic power supply while selling unused power back to the utility supplier via the electrical grid.

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  1. I

    Why do wind turbines pitch their blades?

    Hi all. I'm new to this forum and to wind turbine technology in general, and I watched one of these one-minute videos explaining why wind turbines pitch their blades but it doesn not make sense to me. Why don't you just get a bigger generator? You'd get more energy for the same blades, same...
  2. hagopbul

    De-icing the wind turbines in Texas

    Summary:: how we can de ice the turbine in case of sudden frezzing like what happened in texas hello all : i was watching the news and saw the news talking about frezzing of wind farms in texas state , and losing about 35% of the energy due to that problem can we use the following methods to...
  3. T

    Fluid flow around a wind turbine blade -- help please

    I have to estimate the Reynolds number of the fluid flowing around a blade but I only have one detail: the length of the blade is 0.66m. I have no idea how to do it and I got to submit the assignment in a week, I am desperate for help here.
  4. S

    Feasibility of stratopheric wind turbines?

    1/2" kevlar rope has a breaking strength of 31,000 lbs and weighs 7.8 lbs/100 ft. = 116 kg/km So a a bit over metric ton gets you up to 10 km altitude. 2 metric tons at a 30 degree angle. Still gives you 25,000 pounds potential drag without breaking the rope. Working strength is...
  5. jeffinbath

    B Why do modern wind turbines have 3 blades?

    Conventional Wind turbines now have 3 blades. I assume this is a matter of average air pressure. 1)Would a future wind turbine working on Mars with about 1% of Earth’s air pressure need to have many more blades? 2) Would all those Victorian windmills have been any more efficient with 3 sails...
  6. unseeingdog

    Multiple rotors on a wind turbine

    Could multiple, smaller rotors on a wind turbine (on the same shaft) be more effective than a single, larger rotor? Why do most wind turbines have only one big rotor? I was thinking about doing a science fair project on this topic, but I have been unable to find a conclusive answer to this...
  7. K

    Why wind turbines don't have their dynamos closer to ground?

    Why don't the electric generator mount closer to the ground. The advantage I can think is that it is easy to maintain(no need to climb) and reduce weight(reduce tower cost), however the extended shaft will cost more. Does the longer shaft cost out weight the easier maintenance and generator...
  8. S

    I Pinwheels for Wind turbines? In class, pinwheels proved most

    In class, of all the shapes we tested, the pinwheel won in the total amount of current and voltage, power generated. (used a regular fan and blew a bunch of different blade designs) Question is, why don't we see pinwheels designs for turbines? Where else can I look for turbines designs? Thanks.
  9. G

    Understanding Wind Turbine Efficiency: Exploring Betz's Law and Other Factors

    I am trying to understand wind turbine efficiency and the phenomena of Betz's Law. I have a basic grasp of Betz Law which says the maximum efficiency of a wind turbine is 59 % energy capture of the wind swept turbine area (more or less in those words). I understand that when the wind hits the...
  10. Curiosity and a Cat

    Just a Thought About Tornadoes and Wind Turbines

    I was asked a question and since I have no solid answer I'm re-asking it here. The question was about wind turbines and tornadoes/hurricanes. All that raw energy and we've never tapped into it. Here's the question: Why? I understand the difficulties inherent with a project like this but the...
  11. I

    Do Wind Turbines Significantly Alter Weather Patterns?

    As more wind turbines are installed worldwide, I was wondering how much of an impact on weather they could/would have. (Full disclosure: I am not trained, merely an interested non-scientist) Collectively, wind turbines are collecting considerably more energy than Lorenz's butterfly, so could...
  12. Erika Brown

    Wind Turbines and Conic Sections

    I am working on a project for my precalculus class. They are going to study wind turbines and design a wind turbine blade. I am trying to understand the math behind wind turbines myself. Can I relate wind turbines to a study of conic sections?
  13. K

    Wind turbines turning in no wind?

    So last week I was returning from a holiday (by car) and on the way I saw a field with about 20 wind turbines on it. They were slowly turning, as usual. At first it seemed normal but I suddenly realized, by the open window of the car, that there was no wind at all. So I wondered if there was an...
  14. Zeynel

    Wind turbines with many small generators

    Hello, This is not a homework question. I'm not a student. In fact I'm retired. The other day, I was passing by a wind turbine. I thought "wouldn't it be better to have hundreds of small generators with small wings connected together instead of one huge generator with huge wings?" But I did...
  15. R

    How does airfoil design affect wind turbines?

    I understand that when wind hits the blades straight on it spins for the same reason a pinwheel spins when you blow straight at it. But when wind is hitting the "cutting" parts of the blade how does air foil design help there? Wouldn't the lift generated by the air foil not matter since the...
  16. F

    Could wind turbines be used as wind breaks in open farm land

    my question is would a line of wind turbines have a comparable effect to a wind break in reducing wind velocity
  17. D

    Why do Wind Turbines have such large blades

    This might sound like a ridiculous question and I am sure it is (they don't build them like that for fun) but why on Earth do they? I read an article that said the new PMG style turbines only require the shaft to be rotating at 16rpm to generate up to 8.6MW. Is there so much resistance that...
  18. J

    Some numbers with wind turbines

    http://en.wikipedia.org/wiki/GE_Wind_Energy The rotor swept area is 4657 m^2, and wind speed is 11.5 m/s. Produced power 1.5MW. I assumed that the air density is 1.2kg/m^3, and computed, that the theoretical upper limit for produced power would be 4.25MW. This was obtained by computing the...
  19. S

    What about current de-icing technology used for wind turbines?

    I saw those giant wind turbines stopped working in winter, since winter has most wind in four seasons. so, what good comes out of that? while at least 1/4 of time in a year that the wind turbines don't generate power. and wind turbines are so expensive with limited life time around 20 years...
  20. B

    The affects of Lenz's Law on Wind Turbines

    Hi, If an electrical generator induces a current that opposes the shifting magnetic field that creates it then why don't the wind turbines on wind farms just stop turning after a while? Is it because they are not directly connected or drawn on by electrical devices? Thank you all in advance!
  21. sophiecentaur

    Wind Turbines - are they all they're cracked up to be?

    Whenever I see a wind farm, a huge proportion of the turbines just aren't going round. I don't mean in a flat calm, either. Why aren't the stationary ones doing their stuff? What were they put there for? I have a theory that politicians feel that they understand the wind (they are full of it...
  22. B

    Calculating Electric Power from Wind Turbines

    Homework Statement Consider a wind turbine farm that uses turbines with a blade span diameter of 80 m at a site subjected to wind speeds over the range of 4 to 32 m/s. Taking the overall efficiency of each turbine to be 25% and the air density to be 1.112 kg/m3, determine the electric power...
  23. T

    Why are Horizontal Axis Wind Turbines used other than Vertical Axis?

    Why are Horizontal Axis Wind Turbines used more often than vertical axis when it looks like a vertical axis has more of an advantage? Please can you explain it simply?
  24. E

    Generator types in wind turbines

    What are the percentages of types of generators commonly used in wind turbines? To clarify, what percentage are regular squirrel-cage machines? What percentage are doubly-fed machines, permanent magnet machines, synchronous machines, and so on. I'm looking for a general idea of these statistics.
  25. H

    Energy lost from Wind Turbines

    What is the effect of wind turbines on the aerodynamic of the wind system? Since energy is conserved, will excessive turbines lead to a leakage of wind energy and transformed into mechanical energy? [or concert to heat?] Also, what is the effect of the local pressure? Thanks in advance.
  26. D

    Electrical Systems questions (wind turbines)

    Hi, I am currently working on a year placement between my 2nd and 3rd years at university. I'm working at RWENpower in swindon, UK and goto Coventry University in the Midlands. I have a couple of questions about the industry and certain technical issues. 1. I am currently looking at...
  27. B

    Exploring the Pros and Cons of Wind Turbines

    As I live not far from Altamont Pass and often hike the wind energy area, I see the damage windmill blades do to birds by the number of dead ones on the ground. Also, these windmills are truly Star Wars ugly and insulting to the environment visually, not even considering what they do to birds...
  28. D

    Alternative method for power assessment of small wind turbines

    Hello, I am Daniel from La Plata, Argentina and would like some help on a complex (for me) question. I am working with some friends on the development of an innovative wind turbine. We have built several prototypes with diameters of 0.5 m and 2 m. We have tested these prototypes on trucks with...
  29. D

    Understanding 1MW and 500W Wind Turbines

    can someone explain in simple terms what does 1mw wind turbine mean? how many houses can this power? if it is a 500w turbine, how many houses can this power?
  30. K

    Wind turbines - recent developments

    Hello, I have been trying to find recent developments for wind turbines (post 2000) but so far haven't been successful. Does anyone have any ideas as to any recent developments that have occurred (even if you arn't sure, just some ideas that I could research)? thank-you!
  31. K

    Information regarding wind turbines

    Im looking for information regarding wind turbines. A 1.5 megawatt turbine rotates at 20 rpm and requires 338 kiloNewton meters of force. A 100 kilowatt turbine rotates at 60 rpm and requires 19.4 kiloNewton meters of force. Both are gearbox driven generators. Is there a formula that is used...
  32. M

    Wind Turbines for 2m/s Wind Velocity

    I have few question about wind turbine and its theory for the situation, the average wind velocity is 2m/s 1. what kind of vertical wind turbine is the best for the design? helix, Darrieus, "S" shape? 2. for a wind turbine, how to increase it's output current? 3. what is the...
  33. L

    Adding Secondary Battery Bank to Hybrid & Wind Turbines: Questions Answered

    I want to add a secondary battery bank to the hybrid and have that send a charge to the primary battery. I am considering 2 wind turbines mounted in the radiator inlets. I want to have the turbines charge a secondary battery that will feed to the primary battery. I am doing this to...
  34. S

    How does a wind turbine in a tunnel affect the volume flow rate?

    Hi everyone…. I’m trying to evaluate the feasibility of putting what is essentially a wind turbine inside a horizontal exhaust shaft. I have a feeling that this would affect the volume flow rate through the shaft, but am having difficulty proving it. I have found plenty of textbook examples...
  35. K

    Quiet Revolution: Can Our Wind Turbines Power Themselves?

    http://www.quietrevolution.co.uk/ I understand these things can spin, but what I'm questioning is whether they can really produce enough power to even power themselves? I mean, there have got to be a few hundred if not thousand LEDs on each one, as well as a control circuit to control the...
  36. Ivan Seeking

    How to avoid killing birds with wind turbines

    Stories about bird kills caused by wind turbines are common. I really don't see why this is a problem. It seems to me that something fairly simple could be done; lights, sound, optical effects using colored paints...something. Does anyone know much about this?
  37. Pengwuino

    The Mystery: The High Cost of Wind Turbines Explained

    So why exactly are wind turbines so expensive? I mean arent the generators alone $5-$10 million? One of my professors (hes just a physicist though) said he doesn't really understand why it costs so much either. The next week he brought up maybe there's sophisticated equipment making sure the...