hibernicus writes:
I also transgressed. Apology accepted, and an apology offered in return. I consider this matter to be closed.
Yes, well. I’ll chalk that up as another blow to my battered dignity:).
Phobos is right about the efficiency limit. To take all the energy out of the wind, you would have to stop the wind completely. But if you do that, the turbine will be stopped and you’ll get no energy at all. Betz’s Law says that the maximum energy is extracted if you reduce the wind speed by two-thirds, yielding 16/27 of the wind’s power. This is around 59%.
Of course this is for a “single-stage” turbine, and you could in theory take as much of the energy as you wanted using multiple rotors.
Would that be a stainless steel Ruger Mini-14 with a factory folding stock and a 30-rd. mag? 
hibernicus - It certainly wasn’t meant to be a end-all statement…I was just throwing it into the mix of responses to the OP. I agree you can build more/bigger to make up for what is lost in effeciency but, as had been said, I’d note that it costs more (more equipment, more land, etc.) and becomes more technically challanging (multi-staged turbines, etc.).
Anthracite - It’s been about 10 years since my college coursework in Powerplant design (not my specialization), but yes, IIRC, that is all the technology can get out of the wind (thanks to hibernicus for more info on that one). The textbook is still sitting on my shelf…if you’re interested, I could try to dig up some more details.
Good point about other fuel/technology efficiences. I did not compare. From my same reference, I see that solar cells have a max theoretical efficiency of 48%. After a quick glance, I don’t see other types…I assume that is because efficiencies are dependent upon the power plant technology in addition to the fuel type.
Jeeze…Betz’s Law. I had it in a book right here, and forgot all about it. Sorry all, carry on. Just not about (twitch) oil power as a primary (twitch, twitch) electrical generation source…
Quoting myself:
- please insert the phrase “Power Goddess of Vengeance, Retribution & Eradication of Ignorants” where I inadvertently typed “Power Goddess”. Thank you.
Silliness aside: Noise is a problem - to the degrre where the bigger turbines are designed to be run in more or less quiet modes at the expense of power generation. I nicked those figures from the website above: A Vestas V80 2MW turbine - admittedly a biggie (rotor diameter: 80m) has a a noise level between 40 and 45 dB at a distance of 340 m from the tower. OK, 45 dB ain’t much, but 340 m is quite a ways - and if you have a bundle of these things standing around, it doesn’t help.
S. Norman
I think you all are missing the biggest problem with wind-power. You can’t schedule it. You don’t know when it will be available. If you are looking for reliable system capacity you might want to schedule a small portion of your wind resources, but the portion would certainly be much less than more traditional generating facilities. Maybe as little as 20% compared to 80%. Basically this means you still have to sink the capital costs for the other generating facilitities, so to do a fair comparison on costs you would have to include a back-up plant’s cost on the side of the wind farm, plus the wires to the wind farm sized for it’s max output rather than it’s typical output or face the possibility of having to dump energy during the number of hours per year when it’s really blowing.
That being said, I like the wind farms and believe that even though they are more expensive than many other sources they have a place in the mix.
Now I’m trying to remember where I saw the latest twist in wind power, Popular Science perhaps. Anyway there was a short story and artist rendering of the use of two wind turbines enclosed within pipes sitting up on shore with tunnels down to the ocean. Wave action actually drives the air up through the tunnels and through the propellers. IIRC vanes then open letting air fill the tunnel back up as the waves recede then close as the next wave pushes the air through the propellers again. Much more reliable and can be put pretty much anywhere along the coast. Considering the fact that the much of the world’s population lives within close proximity of the coastline this may become very prevelant in the future, that is if fuel cells and hydrogen don’t pan out.
hibernicus writes:
Akatsukami responds:
Ah, I can feel the love. Thanks to both of you. I appreciate it.
Okay, 'fess up which one of you works for the National Geographic Channel ? They just did a little bit on their “National Geographic Today” show, 7 ET, about NY state investing money in wind power. The numbers they gave stated that the price of producing wind power has come down from 40 cents per kilowatt hour to 5 cents per kilowatt hour. They didn’t say where they got this figure.
The following is about the wind farm I mentioned above. This information along with the information that the National Geographic Channel mentioned can be found at the following site, American Wind Energy Association
"PG&E CORP. DEDICATES LARGEST
WIND POWER PLANT IN EASTERN U.S.
PG&E Corporation’s National Energy Group, of Bethesda, Md., will host a ribbon-cutting ceremony today to mark the beginning of commercial operation of the largest wind power plant in the eastern United States, an 11.5-megawatt (MW) facility in Madison County, N.Y., near the town of Hamilton.
The project is located on farm land and consists of seven Vestas 1.65-MW wind turbines, the largest operating anywhere in the nation (eight units of the same model were installed last year at Big Spring, Tex.).
The Madison plant is New York’s first commercial wind farm, and highlights the growing attractiveness of wind energy as a source of electricity in the northeastern U.S. A 6.6-MW wind project is also nearing completion in Wethersfield, Wyoming County, New York. Vermont is home to the region’s first wind plant, a 6.05-MW project installed in 1996, and a 10.4-MW wind facility began operating earlier this year in Somerset County, Pa. In addition, construction is scheduled to begin soon on a second and slightly larger (12-MW) wind project in Madison County, in the town of Fenner.
The following is relevant information about wind energy in New York, the U.S., and the world. (See also: Wind Power New York)"
It is simply “generation economic dispatch” and “availability”, excluding the complications of the PURPA act. The investment cost of the generation type is amortized over the expected life of the unit, y axis at x=0. The slope is the cost of the fuel and the maintenance cost based on hours utilized, x axis.
(below is approximate but shows the economic dispatch with a very poor graph, sorry)
$/kw/yr
…|……-----.
…|……---------------------<Wind
…|---------------------…---- *******
…|……----<Base Coal/Nuclear
…|…***----…
…|…----…
…|……----…
…|….---- <Intermediate Oil/Coal
…|…-–…
…|----…
…|……
…|……
…|. <Combustion Turbine
…|_…
…|…
…|------------------------------------------
…0…8760
…hours/year
Thus, for up to let’s say 1000 hours/year the combustion turbine is more economical … then the oil intermediate units to 2000 hours/year, then coal intermediate and coal base load units to 4000 hours/year, then nuclear base units greater than 4000 hours/year. All are essentially available on demand. There are various economics for hydro units, but they also follow economic dispatch considerations. (The above hours are only illustrative since the current utility economics haven’t been assessed for a few years.)
Wind turbines considering amortization of capital cost and maintenance cost can’t compete with any current generation even with “free” wind energy. Plus the wind units would have to be on line 85%+ of the year, capacity factor, to be even slightly competitive, not considering the lack the availability relative to demand.
Anyone who believes, outside of economics, that wind is a better choice for whatever reason … please feel “free” to pay for it!
funnee, here’s a short story about the wave-driven wind turbines: http://www.msnbc.com/news/493172.asp
Thanks manhattan, that was the generation plant I had read about before. Looks promising and also produces electricity at competive rates.