# Expensive wind turbines

1. Mar 19, 2005

### Pengwuino

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 doesnt really understand why it costs so much either. The next week he brought up maybe theres sophisticated equipment making sure the gears and turbines are spinning at the correct frequency. Anyone know the absolute answer to this?

2. Mar 19, 2005

### Clausius2

I think wind turbines are designed in such a way to optimize the absorption of kinetic energy from the wind, and such a mission requires to refine a lot the aerodynamic shapes of the blades, and also to reduce the blade's weight by means of using lighter materials such as carbon fibers. Taking a look at one of these giant monsters I think the designers had a challenge getting the alternator up there and reducing the friction between shafts and journals in such a machinery.

3. Mar 19, 2005

thats exackly it. If you want an efficient turbine, you need to have it be aerofunamic, as little friction as possible and very efficient. Wind power is not that much of a power source so if you want the turbine to produce a lot of energy, it wil have to be top notch design. Also, have you ever seen any of these turbines. Theyre not that small. A wind turbine is usually twice the size of a car which is a lot of materials and dough.

Regards,

4. Mar 19, 2005

### willib

5. Mar 20, 2005

### Clausius2

and so they don't always have to be so expensive...

6. Mar 20, 2005

The larger a wind turbine is, the less expensive it is.
http://www.ucsusa.org/clean_energy/renewable_energy/page.cfm?pageID=128 [Broken]

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the cost per unit of electricity generated from smaller turbines is higher than that from larger turbines, so the payback period is longer.
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Last edited by a moderator: May 1, 2017
7. Mar 20, 2005

### Billy T

I am just a physicist so take the following with a grain of salt :tongue2:
Part of the problem is that the power in the wind goes as the cube of the wind speed. You need to make the machine work in the typical wind speed, perhps less that 20MPH and yet survive the worst storm in the economic life of the machine that might be 20 years and 100 MPH gust. That is you must build it to resists (or some way shed) power densities incident on it that are nearly 150 times its start up power level!

If your modest 100 HP car had to have a 15,000 HP engine in it, for use once in 20 years, think what it would cost. :yuck:

Last edited: Mar 20, 2005
8. Mar 20, 2005

### willib

http://www.speakerfactory.net/wind.htm
"Latest Selsam Wind Turbine Sets World Record! "
dont know why he calls his site speakerfactory !?!
But it is a very, very interresting site.. he uses multiple propellers on a single carbon fiber shaft..

9. Mar 20, 2005

### Staff: Mentor

I tend to think of it the opposite you guys are thinking of it: its not that the turbine is that expensive, its that the they don't produce much power.

10. Mar 21, 2005

### Clausius2

I was not thinking of the payback, only the cost of design and building it. :tongue:

Last edited by a moderator: May 1, 2017
11. Mar 21, 2005

### Billy T

I think your view very valid. My post showing that the peak power incident on the machine in economic life is about 150 times greater than the start up power level, is just another way of saying that you get little power for the size/ strength of the machine you must build.

Wind power available can not be matched to the demand - that is why it is never going to totally replace sources that can be. That other form of hidden solar energy, hydropower, is much better in this regard. Some have suggested that if wind machine is on relative flat topped mountain, you could improve the ability to match the demand with a mountain top reservoir -"pumped storage" - obviously more cost, but may improve the overall economics.

12. Mar 21, 2005

### ohwilleke

Another factor in the cost of wind turbines is the lack of mass production. Design costs are a significant share of total cost right now, because there are relatively few turbines in service and they have new designs. In twenty years or so, when patents run out on those designs, one would expect prices to fall.

13. Mar 21, 2005

### willib

not meaning to be picky , but how is hydropower a form of solar energy??

14. Mar 21, 2005

### Clausius2

It couldn't rain if we hadn't sun. By this same reasonement, I think that every energy in our planet is enhanced by solar energy.

15. Mar 21, 2005

### Billy T

I think it is useful to recognize that wind, hydro, and wave (not tidal) power as "hidden" solar energy - your dropped the adjective "hidden."
It is less useful, but still true that coal is also ancient solar energy and very probably true of natural gas also (Thomas Gold and a few others think it is from deep in the Earth.) Even "nuclear fission" energy is from some old supernova or slow cooked by neutrons in some ancient big star. It would be hard to claim "nuclear fusion" is not solar power as that is the sun's power. In short, every form of energy I can think of except tidal power is solar energy, only, IMHO it is not very useful to note this, except for the first three that are relatively recently converted versions.

I also like to note that there is far more solar energy stored in a salt dome, than if that same dome were full of oil. Only mankind has not yet found any way to economically harvest it.

16. Mar 21, 2005

### willib

i agree that wind , coal & even nuclear energy are all forms of solar energy ,as are most .. and i suppose that if the sun was not there , the water would be ice..
please excuse the way this looks , i suppose that there is no way to disagree in print that dosent sound horrible when you read it..(thats as far as i can go to imagine that hydropower is a 'hidden' form of solar energy..)
as for the salt dome , what do you mean??

17. Mar 21, 2005

Latent solar energy

http://www.csun.edu/~vcgeo005/Energy.html

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"The overwhelming preponderance of geological evidence compels the conclusion that crude oil and natural petroleum gas have no intrinsic connection with biological matter originating near the surface of the Earth. They are primordial materials which have been erupted from great depths."
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If hidden solar (hereafter referred to within the present document as latent solar) means charged by the sun during the lifetime of the earth, then isotopes with fusion fuel and fission fuel potential are not forms of latent solar energy resources.

If fission and fusion qualify as latent solar, then so does tidal power qualify as latent solar since our moon came from the same place as our fission and fusion fuels. If fission and fusion do not qualify as latent solar, then geothermal energy does not qualify as latent solar either since geothermal energy potential is charged by the decay of geologically-embedded radioactive isotopes.

What energy stored in salt domes are you thinking of? If it is http://home.flash.net/~lbh/whatis.html, that seems to be geothermal and therefore not latent solar, as explained above.

Last edited by a moderator: Apr 21, 2017
18. Mar 21, 2005

How the hydrologic cycle gives hydropower its latent solar energy status

The hydrologic cycle is powered largely by the sun.
http://people.howstuffworks.com/hydropower-plant3.htm

Water is evaporated by the sun from low elevations (such as low lakes and, especially, the earth's oceans). It forms couds in the sky and falls as precipitation on mountains from where it flows in rivers back down to low elevations. When the water is at a high elevation, it (like anything else at a high elevation) has potential energy. As the water flows down to lower elevations, it releases that potential energy. Tapping into that potential energy of the high-elevation water with hydropower generation stations is ultimately tapping into solar energy since the reason the water is at a high elevation in the first place is that it was evaporated from low elevations at least partly by the sun.

19. Mar 21, 2005

### Pengwuino

Aww look at my cute thread blosm :D Thanks for hte info guys!

20. Mar 24, 2005

### willib

i hadnt thought of that , but you are absolutly correct..
i did not think of how the water got to the higher elevation in the first place..