Westerlies??? …. you surely can’t be serious; you have just stated yourself that you are asking about easterlies, and westerlies are the exact opposite.

The Hadley cell is a circulating system which is driven by upwards movement by convection in the tropics (as a result of heating the air), and downwards motion in about latitudes 30 degrees both north and south (the "Horse Latitudes" in the case of the northern hemisphere) as the air cools. Therefore the high altitude air between the two moves towards the poles, and as a result of the Coriolis Effect it is deflected to the right in the northern hemisphere (and to the left in the southern hemisphere), i.e. eastwards in both cases, thus creating the Jetstream. At sea level the air returns towards the Equator, and again is deflected to the right in the northern hemisphere (and to the left in the southern), thus giving rise to the Trade Winds.

From the phrasing of the question this looks like a piece of school homework; please next time do your own homework rather than asking the online community to do it for you!! An internet search on "Hadley cell" should provide all this information, along with information about the polar cell and the Ferris cell, which give rise respectively to the polar easterlies and the prevailing westerlies.

Note that the westerlies are very far from constant, merely prevailing, because the Ferris cell is a secondary one, driven only by the friction created by the upward motion of the polar cell in latitudes somewhere around 60 degrees (both north and south) and the downward motion of the Hadley cell in the Horse Latitudes. The air in the Ferris cell moves in the opposite direction from what convection would suggest if you were to consider this cell in isolation. The air moves as it does because we have opposing sets of forces, but the frictional forces are USUALLY stronger than the convective forces within the Ferris cell. Thus the Ferris cell is characterised by turbulence and instability, and this in turn can create undulations in the polar front and these can be the nuclei for the start of depressions, which are characterised by winds rotating around the centre (anticlockwise in the northern hemisphere), and usually by associated frontal systems. Likewise, localised regions of high pressure can arise, characterised by winds rotating clockwise in the northern hemisphere, and normally with no fronts (although I have known occasional exceptions).

So winds in latitudes about 30 degrees to about 60 degrees (either north or south) CAN come from any direction, and at almost any strength from zero up to storm, but they are more often southwesterly than any other direction; this is what "prevailing" means in this context.

Note also that westerlies in the southern hemisphere are much stronger and more stable than those in the north, because of the near absence of land at those latitudes in the southern hemisphere. The "roaring forties" are such because with the solitary exception of Cape Horn they meet no land at all as they blow around that band of latitude.

For example, the Roscoe wind farm cost about $1.25m/MW of capacity. Assuming wind resources are UK average, the capacity factor will be bout 30% (UK average is 28-31% depending on year). Therefore each MW will generate about 2.62 million kWh/year, or $262k/yr.

The Danish Wind Energy Association claims that maintenance costs are under 3% of initial outlay, so you should expect that over a 25 year life, excluding decommissioning costs and assuming $0.10/kWh, a wind turbine has a yield of about 8% annual return, assuming that you put aside the maintenance money at the beginning, an annual rate of interest of 3% and a rate of electricity inflation of 3%.

Assuming $0.05/kWh, then the rate of return is just under 5% over the 25yrs.

In general, coal is cheaper than wind without subsidy; but we can’t really tell how much. In the US, the subsidy is equivalent to about 1.2 cents/kWh, and that has led to an explosion of wind power. Since I’m not aware of any countries that have large wind power without some kind of encouragement, I can’t think of any empirical data to show just how competitive wind is.

That said, there are very good reasons for either taxing coal or subsidising wind. Coal adds social costs in terms of billions of dollars in healthcare and agricultural damage from air pollution plus the social costs of climate change. Considering these costs are typically estimated at between 1-10 cents per kWh, the US subsidy looks justified to me.

And… how far is that prarie away from a city?

But that is no reason to not *start* doing it; why should we be reliant on an energy source that has a finite quantity?

And re Feinstein’s comment, she didn’t say that she was only concerned about the "aesthetics" of the project; her objection was that the land in question had been donated or purchased by conservationists with the intent that they would be protected forever, not used for energy projects.

The manufacturing of the components isn’t so clean

What is the deal with Carbon Dioxide (CO2) when an engine or fire burns it produces Carbon Monoxide(CO) (a poison gas), When anamals breath they produce Carbon Dioxide (an inert gas), The fizz in colas and beer is Carbon Dioxide , you can check the soda fountains at your local conveniance store to see what gas they put into the cokes
If you want to clean up the CO2 plant some grass ,flowers and trees.

Elevation often gets more wind speed but adds cost and greater chance of falling over

blade length adds more weight and greater chance of broken parts

But speed is critical in both design and power output. If you double the speed of a car, you have four times the wind resistance. The energy in the windflow is a function of the square of the speed, but for a turbine, the change in energy is even greater because as you double the speed of the wind, you also increase the speed of the turbine blade, which further adds to its energy output. If you want to see this in a mathematical expression, the best place to go is the American Wind Energy Associations website, and look for the page with the wind power formula or equation. Or you can just google, "Wind Turbine Power Formula," and the link to the AWEA website will take you straight to that page. In that formula you will find variables for the air density, which of course decreases with altitude, turbine blade swept area (blade length), and the velocity cubed, (to the power of 3). So by looking at the formula, we can easily see that doubling the blade swept area will double your output, but doubling the wind speed can result in 9 times the energy. Increasing elevation does add a small benefit of wind speed, but at an ever increasing cost for each unit of height. This is why most turbines are only as high as they need to be for the bottom of the blade sweep to avoid the turbulent air near the surface. I hope this helps explain things for you, I’ll include some sources below. Take care Hardip, Rudydoo

Wind on the other hand, doesn’t even seem to be as cost effective as hydroelectricity, of which there is an abundance of, just north of the border in Canada. But nobody cares. They’d rather have Google build a giant windmill covering the entire east coast than do business with the Canadians.

Remember after 9/11 the first act of defiance was to rename potatoes "freedom fries". People actually wonder why the dollar’s value heads south.

Cost – variable… for either. Both can be achieved with relatively minimal costs (depending upon exactly what effect is desired) – both can be scaled up quite a ways before issues arise.

Technical limits… a bit like costs – it varies – and depends what you are trying to achieve. If you want to pump water from a well in Oaklahoma or heat water for a swimming pool in Arizona – then wind and solar power respectively will require very little in the way technology beyond what we may already have. The real limiting factor is energy *storage* and transmission.

Environmental impact – - solar energy likely has the advantage here. Solar power cells can be installed upon the roof of your house or office building without having any significant effect upon the local environment. A windmill out on your yard could be a nuisance for your neighbors….

YMMV

Thanks for the comments.

Seriously, the output of a wind farm depends on three things:

1. The number of wind turbines. This could be anything from one unit to hundreds.

2. The ratings of the turbines. Modern land-based wind turbines are 1.5-2.5MW, while units designed for off-shore application are 3.5 – 5MW each.

3. How fast the wind is blowing. On average, a typical wind farm has a capacity factor of around 35% meaning that the overall, long term output is about 35% of the maximum capability based on the number and size of individual units. The reason that this is so low is that the wind does not always cooperate.

Sorry but there are very few "pros" that anyone but diehard environmentalists can conceive of. These might include nonsense such as "green economy" and well paying jobs and technology advancement, but they are all false claims!

Cons:
1. It is only "free" initially when on public lands or oceans. When it moves into the agricultural areas it will cost a fortune due to lease agreements with farmers to place windmills on their land.
2. It will reduce agricultural production and grazing lands substantially. Who wants to grow anything in and around windmills, when you are getting annual surface rentals that exceed the value of agricultural product? Who wants their livestock to be subjected to high frequency noise?
3. It will cost 2 X the cost of conventional electrical transmission lines, which taxpayers pay directly, since the baseload of conventional power must be preserved , while having the ability in peak wind generation periods, to carry the doubled overflow load.
4. It will kill hundreds of thousands of bats and migratory birds.
5. It already costs, despite heavy taxpayer subsidies, 50% more than conventional power and will actually become MORE expensive as mass production occurs.

Wind power is one of the few examples of dis-economy of scale that I have ever seen. Usually mass production creates economy of scale, but not in this case. Ultimately wind power will cost 2-3X more than conventional energy!

To Rudydoo – Your philosopy is great but your concept of economy and societal benefit need work. Please keep your comments to yourself. I do not appreciate them, need them and nor will I really heed them. If you want to answer someone’s question then go ahead, but mind your own business!!

There are also mechanical and political benefits. We all know after the oil embargo of 1973, and the gulf war what it means for our country to rely on foreign oil. Wouldn’t it be nice if we only shipped in 20% of our energy instead of 60% the next time something like that happens? Our home has been powered by the wind and sun for years now, but we still remain connected to the electric grid. Last year alone there were two power failures in our county that lasted about a half day each. In both cases, we were not aware of them because our solar array and wind turbine kept on feeding the house. It’s difficult to put a price tag on something like that. Did you know that there are over 100,000 homes and businesses in the United States alone that use some level of solar or wind power to operate their electrical devices, that’s good news.

Beyond the mechanical, political and environmental benefits however, lies a less obvious benefit, the social benefit. Right now we pump oil out of the ground, and mine for coal. The process of getting those materials to market involves shipping, military escorts and other activities that use up a good portion of that energy as well as putting lives at risk. Jobs in solar and wind power are higher tech than jobs in coal mining, oil drilling and shipping, and there are more of them. Using more wind power would require us to put more people to work, and increase our education base because the work involved requires certain skills. I would personally like to take all those people out of the coal mines, send them to school and put them to work building solar panels and wind turbines. Nobody would have to die again in one of those dark holes in the ground trying to find food for our hungry power plants. They could work on a factory floor where they would not be exposed to coal dust, radon and other toxins and dangers. Most of our solar and wind resources are spread pretty evenly over the middle half of our globe, so everyone has access. This puts people in Bogota on a more equal footing with people in Boca Raton by giving them access to electricity, heat and clean water, and the education to use the resources that provide those things. Oil, coal and natural gas is generally piled up in a few places, such as Russia and the Middle East. This gives those countries and the richer governments that rule them more horse power in bargaining for the other resources of our planet. These are the things that wars are made of.

The one thing that always amazes me when I read forums like this is the amount of misinformation there is about the subject. Take Bad Moon’s complaints about wind power for example. Our wind turbine has been powering our home for 10 years now, it has killed fewer birds than our picture window, does not blot the landscape any more than the power lines running to our neighbors home, and the animals and plants that graze and grow beneath it have never noticed it. Yet Bad Moon is happy to complain about the perceived problems of wind power without ever having owned or operated a turbine. Well power companies are finding the same thing out today we have known for years, and that’s why they are busy buying and installing turbines. As a side note, I clicked on Bad Moons Avatar to see what other answers might be posted, but they are private, no surprise. I encourage you to look at mine, they might give you some more information regarding your subject, and y

There are really too many variables too give a good answer here, if you would have no problem spending $20,000 (and wouldn’t totaly freakout over $50K+) then contact a local consultant for more information. If you can’t afford that, it is probably not really worth giong any further since $20K is at the very bottom of the price range for that size of instalation.

is there any wind?
how strong?
all day?
or just part of the day?
what do you consider "a small scale wind generator"?
does your AC use 110 or 220 power?
(it might uses both. although 5 ton isn’t all that large.)

where are you going to put this?
how are you going to anchor it?
is it allowed where you live?
are you going to have an alternate power source for when there is no wind?
in which case, have you looked at what it takes to hook up to the power grid?

maybe you ought to talk to someone around where you live about this.

Dutch wind mills. Pumping Water, Grinding Grain into flour. Sailboats. Drying food. Drying clothes. Making Salt.

Also they were used to turn large turbines that milled grain or moved machinery (remember those large fan looking things from old movies of European country sides).

Also used in sail boats.

The issue is more of a ‘when’ than an ‘if’. The most promising are wind and biomass. Turbines are a well-established technology, so thats why we are starting to see major increases in wind generation.

Biomass is pretty promising for replacing our liquid fuel needs, but currently concerns about competition with food and land-use changes are holding it back. However, numerous researchers are investigating non-food based biofuels such as algae or jatropha.

Solar power gets a lot of media attention, but the technology is still too inefficient and expensive for large-scale use.

We are not likely going to see any new major hydropower, like Hoover or Grand Coulee dams, but quite a few people are looking at microhydro systems (i.e. underwater turbines that sit in a river or off the coast but do not block the entire path of water).

Its only a matter of time before the technology for these alternative energy sources is developed enough to be cheaper and more efficient than current fossil fuel sources. However, its hard to tell when this is going to happen (i.e. next year or in 50 years).

Power usage is increasing every year, so the increase in solar and wind and nuclear has to be equal or greater than that increase, or fossil plants have to increase also.

.

If the facility is not in existence, you have to consider all of the energy required to get the facility operational before you can make the call about whether or not it saves fossil fuels. I would expect hydropower installations like dams, etc. to take a tremendous amount of energy to get built before they could ever generate one KW of power without fossil fuels.

They are so unreliable that they are almost completely useless for powering anything requiring a constant power source, such as a city. When the wind dies, or a cloud obscures the sun, you can’t just "fire up" another fossil or nuclear power plant or spin up another turbine in your hydro dam. The existing plants need to operate at nearly 100 percent of the predicted load so they are constantly capable of picking up the slack when the heavily subsidized and economically flawed "alternatives" suddenly die.

Run search for "Wind Generators"

(Available from 100 watts or less to several megawatt sizes.)

If you are up for building the turbine this can drop the costs to as little as $200. The only real expense for a DIY build is the generator which can be a DC motor. A well positioned turbine can produce over $2000 worth of electricity a year, so it’s well worth the effort.

It’s not that difficult to mount a turbine. You need some steel piping to mount the turbine on and also some supporting ropes to make sure it doesn’t blow down in strong winds.

The largest wind farm in the United States is the Horse Hollow Wind Energy Center in north central Texas. It’s rated output is 735 megawatts, which is about the same amount as a small nuclear plant.

The relatively flat and featureless terrain of north Texas does not provide many obstacles (friction) for the wind, allowing it to reach higher speeds and be more constant. This same effect is taken advantage of in the oceans.

The power that is required to run the wind turbine at the same speed normally comes for the grid; (grid integrated wind turbines). You are refering in this case to the fixed speed wind turbines, where it’s speed is governed by the synchronous speed of the AC frequency of the national grid. Normally this does not require much power without wind, because there is little drag and the rotation continues mainly by inertia; only little power is required to maintain this rotation against resistance. When there is wind, depending on wheather the turbine is direct drive (gearless) or with a gear, it is adjusted to give the optimal torque on the generator.

Are you asking if a wind turbine is ever operated as a motor when there is no wind?

I don’t think so, what would be the reason to do that?

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They are noise and visual pollutants too. Hollands idea of building them at sea is the best idea I have personally seen.

Old auto generators were used too- in fact http://www.lindsaybks.com carries a reprint of a 1945 LeJay manual where they have a number of plans using automobile generators and tips and tweeks to get them to produce well at lower wind speeds, even direct driven.

Flat stator Axial Flux AC mills have been popular because they are reasonably easy to fabricate and will produce useful amounts of power at low speed. Also available through Lindsay are some books on home brewed power, Hugh Piggott’s is probably most copied because it is a simple design. Even a book pulished by the UN aimed at thrid world development agencies has one of these Axial Flux designs in it. His homepage is here: http://scoraigwind.com/ His propeller plans in his books are a basic design that works well, and has a proven track record of reliability.

One thing- NEVER use plastic pipe for blades. They break far too easy, ABS is too weak, and PVC will degrade exposed to sun light like it is. When they break they travel great distance with great force behind them- they can kill people. Unless your nearest neighbor is 4 miles away- just use the wood, or the commercially made blades. If you try working with metal- fully understand what metal fatigue is before you start for the same reasons.

At night, after everyone has gone to bed, the household demand is as low as a few 10s of watts – an alarm clock or two, the displays on a VCR and a microwave, perhaps a cell phone charger and a cordless phone base station.

Then the refrigerator will kick in and you have a very short-term peak load of over a kilowatt, as the motor starts, which then settles down to a couple hundred watts. But if it is a frost-free refrigerator, when it goes into defrost mode the heater may draw between 1/2 and 1 kW.

During the day you will switch on some lights, perhaps some electric cooking appliances, maybe a couple of air conditioners. You can easily have a demand of 5 kW or so, sustained for several minutes. If you have an electric stove, electric water heater, or electric dryer, you add between 3 and 10 kW to that load for each appliance.

So, it comes down to this: you add up the power of all the appliances you think you will ever want to run at the same time. You should add 25% to allow for non-unity power factor and to leave some excess capacity to start motors. That’s your minimum wind turbine. If you have a house with electric heating appliances, it is likely to be a shockingly large number. (although if a lot of your demand is due to heating, then the 25% safety factor is too generous.)

However,
There are economies of scale in wind turbines, i.e. larger machines are usually able to deliver electricity at a lower cost than smaller machines. The reason is that the cost of foundations, road building, electrical grid connection, plus a number of components in the turbine (the electronic control system etc.), are somewhat independent of the size of the machine.

On our farm, we have it run straight into our house to power lights/heater/well/dishwasher/etc. Any electricity we don’t use we sell to the local power company and the same thing happens, it gets sent out along the same lines the normal electricity follows.

Just the turbine itself will not work. In order for a generator to connect to the power grid directly There are things that have to match, the voltage, the frequency, and I think the power factor and something else I cant remember. If these things are not correct your system will go unstable. There are systems that can regulate this stuff for you however I don’t know if there are any for singular homes yet because the technology is fairly new.

Other things you may not have thought about:
Is your area consistently windy (and at a fairly consistent speed?)
Are you allowed to put this in your yard by home owners associations to city governments?

One home would probably be a little bit too big of a load for the 20kW wind driven generator on a relatively still day.

Perhaps 8.

Production of wind generator…
A wind generator has a threshold to start generating, like 12km/h.
It may generate 50% output at 18km/h and 100% output at 24km/h.
These figures depend on the design.

Wind availability…
In what is called a "good/excellent location" for wind, the penetration may be 30%. That means the total production is 30% of the full rating. That means 6.6kWh x 24h per day, averaged over a year. This is very dependent on the site, winds, time of year and the wind generator itself. Call that 160kWh/d.

Load per house…
The average load is a vague thing, perhaps something between 3 and 24kWh per day (or any other number snatched from the air). This depends very much on the community, the culture, the location and the time of year. It is also a statistical measure, not an indication of the peak power demand at particular times. For example, do the houses have air-conditioners, clothes driers and heaters. Does everyone switch these on at the same time each day. This is still a rate where the houses take some care with electricity use. Divide your electricity bill by the rate per KWh and the billing period in days to see how you compare for KWh/d.

At that rate, we could hope for 160kWh/d / 24kWh/d etc, so between 7 and 50 houses (on average over the year). This analysis gives no guarantee there will be enough power at any particular time. The excess power to demand at any particular time also needs to have a place to go – some sort of storage system. Batteries for even this modest power level would be huge, but also difficult to determine exactly how big without actually trying it out. For the feel of it, to store a day’s good operation, perhaps say 160kWh/d. Let the battery be 240V, it would be 666Ah capacity. A typical car battery is 12V at 40Ah.

This power we are talking about is only useful when the houses are statistically averaged (they don’t all switch their heaters on together). It should be seen as a fuel saver for the existing power system. How much fuel is saved depends on , the way electricity is used in the houses, and when the wind happens to generate electricity.

It works must better if the wind generator is connected to a grid where there are a lot of houses (many thousands) over a large area, say one or two states in the US. The connection uses a special inverter that can regenerate the energy from the wind generator at the correct phase and voltage to export power to the grid when required. This distribution over geographical area and a large number of houses evens out the load variations. Basically the wind generator exports power to the grid to supplement the power the grid gets from other sources. This is perhaps the best way to achieve a meaningful result, though if done on a grand scale the grid itself may have stability problems that come from the base load steam stations not being able to vary their output quickly. The bigger the variety and the geographical area the more likely that the system works, but individual lines in the network need to be considered too. Not simple.

If there is no grid, like on a small island, the next best thing is to continuously run diesel generators that are specialised in that they can run for extended periods with small loads when the wind is good, and instantly take over when it is not good. Once again the wind generator is a fuel saver, but less effective because the houses may all increase and decrease loads simultaneously. The diesel generators must be big enough to generate the full load at some times, and there may not be enough load to use all the wind generator output at other times.