Wind generation pulls a tiny fraction of energy out of the wind. Consider the relative size of all the worlds wind generators to the available wind space - an area equal to the surface of the earth and several miles tall.

Yes, and it will reduce the wind damage to structures like buildings and trees too.

And then there is the damage due to the falling windmills to conseder.

The damage caused is minimal due to the fact they generally don't fall down and they are located in areas where if they did they are unlikely to land on anyone, even when this happens.

http://www.liveleak.com/view?i=cdd_1203701257

Jack - A power engineer who actually designs and commissions wind farms.

It would be a big plus if it can turn a tornado / twister / hurricane into a whirlwind.

Don't worry we have top men working on it. Top...Men.

http://www.uberreview.com/2007/07/what-a-concept-emissions-free-tornado-power.htm

A tornado for every backyard, I say.

I have a great deal of difficulty understanding why otherwise intelligent people imagine they will get 200 Mwatts of electricity out of a man-made tornado or solar chimney. One cannot get more energy out than one puts in, and providing hundreds of megaWatts of heat is not easy. Yes, a turbine in a chimney can turn the spit for the roasting meat, but the efficiency is low, and the temperature difference is high. The idea that simply warming air will make it rise with useful energy, with or without a proper chimney, is entrancing. After all, that is what powers thunderstorms (with some help from water vapor) and sailplanes. However, if you build your thingee in the desert, to get the hot surface to heat the air, you will probably find that, if "nature" intended the air to rise, it has already done it without your help. Likewise, building the chimney up the side of a mountain won't help. If the air will rise in a chimney, it will rise without one. Usually, the turbines to extract energy from the "tornado" are at the base (not at 3000 meters in the air), so the kinetic energy of the incoming air is very limited. We read of grand plans, but has anyone made money from such a scheme?

With conventional wind turbines, the situation is different. One does not have to build some sort of vortex generator to get the wind. You build the turbine where the wind already exists. A perfect turbine can extract about half the kinetic energy of the wind through the disc. (Perfection isn't necessary, when the wind is free) Clearly, the wind speed downwind is decreased, but with turbulent mixing you won't notice the difference. (Behind an aircraft propeller the wind is increased, but across the field you don't feel it)

Those who espouse chaos theory and the "butterfly effect" would say that if the wings of a butterfly in China can trigger a hurricane somewhere else, then of course the wind turbines will alter the climate. That's a big if. Has anyone evidence that butterflies can do that? Isn't the effect of the butterfly insignificant compared to that of a jet aircraft?

The reason winds are there in the first place is to move heat from the tropics to the poles. The amount of heat to be transferred is approximately constant (about as constant as the solar constant), and if something, a turbine, a tree, or a mountain, obstructs the flow, the heat will be transported somewhere else. If you remove energy from the air in Texas, slowing the flow of heat, the rest of the atmosphere will compensate to keep the heat flow the same. (By analogy, the Mississippi river exists to move water to the Gulf of Mexico, and putting your finger in the river will not reduce the flow) Were this not the case, there would be warming in the tropics and cooling at the poles which, of course, we have not observed. (According to those who measure temperatures, people at NASA, "global warming" stopped ten years ago)

In short, the consequences, climatewise, of wind power generation are unmeasurable.

As I drove through the Midwest this summer, I had a thought about ringing the small towns with the wind generators. There are 100's if not 1000's of them in Iowa.

Since tornados are a problem, I would think that having them around a town could be networked as to wind speed and direction and detect a tornado before the eye could pick it out? If all the wind generators were monitored, and a few are sourcing wind from the West, and others are sourcing wind from the East, that may indicate a tornado? I would think there could be enough data generated to indicate something is developing?

If anyone knows the right people, you might suggest this?

Generally in the Midwest, there are doppler radars which can track storms and detect tornadoes fairly well. As for "the eye can pick it out", while the actual funnel cloud may be difficult to see (mostly because people are inside buildings), the storm which spawns it is usually very obvious. Interestingly, a tornado touched down in my back yard, toppling a large tree before going on to remove roofs, etc. nearby. I watched the tree go down, but I could not say I saw the funnel, just the blowing debris. I was, I suppose, too close.

I would suppose that using a wind turbine as a tornado detector would be like using the Titanic as an iceberg detector. A more expendible instrument would be better.

Guess I'm old fashioned but the barometer seems a better choice without reservation

Hello realist,

There is no consequence of the so called sucking of energy from wind, other than it provides extra power.

'Wind' is not a 'power-bank'. It is not something like electricity which will slowly run down as a charged battery would.

The wind 'down-wind' of a 'wind farm' is no less powerful than it was before it went through the wind farm.

As long as the sun shines and the earth spins there will be wind, in almost all cases more than we can make use of. If the land on earth was completely filled with windmills, there would be just as much wind at sea directly off land as there ever was. The you would still get the 'doldrums' exactly where they are usually.

Which is, a belt of calms and light baffling winds north of the equator, between the northern and southern trade winds, in the Atlantic and Pacific oceans.

This is a natural phenomena and will not be affected in the slightest by wind mills.

I may be old but I still believe E=MC^2 is still valid which makes your comment invalid unless of course there is a reduction in mass, and I don't believe there is.

Do you mean that the molecules hit the vanes and then drop to the ground? (where they are accumulated in buckets for a calm day).

Hi..

Electricity is also extracted from flowing water. Does this change the quality of water?

My dear the answer is no. Only some turbulence is created in the wind after it passes through the blades. Generally speaking the turbulence gets settled at a distance approximately about 8 X Dia of Blades. After this distance you can put up another wind turbine without effecting it's power output. Ofcourse, there is issue of turbine noize. But, it is minor as most machines are large and the nacelle assembly is mounted a good 50 meter or more above the ground.

Anil Tiwari / New Delhi

Anil Tiwari

With hydro power the dam / reservoir will loose water.

Amazing how many educated persons believe in "perpetual motion". Basic principle - you cannot extract energy from one system without changing the energy, potential or kinetic, in the system the energy is extracted from.

I agree the impact is minimal but there MUST be consequences.

realist,

The wind that is 'extracted' in fact, is not extracted. It is used to spin whatever can freely move anyway. Any turbulence will dissipate soon after the wind has passed through the wind mill. Even if the energy had been 'extracted', your word, the sun and spin of the earth will make more wind anyway.

In that respect 'wind' can be seen as a perpetual motion device, as it will work until the earth stops spinning, the time frame is billions of years, so effectively it is perpetual motion. Though this point could be argued. When does 'perpetual motion start and finish, is it in the life of the earths time frame?

I'm with you. I am also aghast that other posters feel there is no consequence. True, at today's deployment levels of wind turbines, there is probably no way to measure the change, but it's there. But then again, we can increase the CO2 in the atmosphere by .01% and people howl. Go figure.

Hi...

You ought to brush up your concepts of perpentual motion. The ocean and air flow systems on this planet draw energy from the sun, earths movement and the moon etc. It is due to the influence of these forces that the wind blows and the tides rise...otherwise, this planet will appear to be dead wherein only calm prevails.

To build a perpentual motion machine you'll need a location where non of these forces are able to cast their effect!!!!...maybe away from the solar system.

Surface wind speeds get effected due to roughness factor of the earths surface, forests & buildings etc. Roughness factor over water is assumed as '0'. Then it goes up as 1,2,3.. Wind turbines are put up in high wind zones. Several such sites are identified across the world. One such site in India is called Kayathaar. It faces the Palaghat Pass which is a 30KM gap in the 1500m tall Western Ghat mountain chain. Here the winds from the Indian Ocean pass through this natural gap and gain high speed due to the venturi effect. This has phenomenon resulted in hundreds of wind turbines coming up in this place totalling to over 500MW of installed capacity.

Anil Tiwari / New Delhi

But there is additional headloss through the turbine (or other device) used to generate power and thus an increase in head on the upstream side of the device. And in cases a large dam is built to further increase the drop through the turbines.

Non issue. The high pressure flows to the low pressure. More drag eg. windmills, trees, uplifting mountains- causes a higher differential due to the sun energy and the earths rotational energy that are so large compared to what even a mountain range converts and redirects is insignificant. Think of it as an island in the ocean, it can not stop the tides or currents. If it is large enough it can redirect them, amplify or mute them in one area but this is offset by another area. And unlike an island a windmill or mountain raise only a fraction of the depth of the atmosphere.

Brad

Bearing in mind that the wind you describe is within the earth's envelope please elaborate upon the leverage described as effecting the earth's rotation...

he didn't really mean slowing down... he meant dumbing down. won't affect rotation at all!

Hi,

As global wind direction is against the earth's rotation, the wind MUST be slowing the earth down.

The earth spins within its own envelope of atmosphere and the friction between the earth and the atmosphere causes the atmosphere to apparently move. The earth spinning at about 1000 mph (1600 Kilometers Per Hour) and any winds that have been recorded that I know of, are a pretty small fraction of the total spin speed. ~ 10-20% max. Even the wildest 'Twisters' rarely go above 200 mph (32 Kilometers Per Hour, which is where the 20% comes from.

It could be argued that a single giant Coniferous Redwood of California would produce as many vortices, and or turbulence, air disturbance, whatever you want to call it, as a wind mill.

Hi all,

in answer to post 15 I sent post 33.

Please note: I did bold in normal type, this was to copy and past the relevant piece from the post I was answering. (Number 15).

Sorry if it made it look like my "statement"

Sorry for the mistake.......................

Shouls be

>>> 320 Kilometers an hour <<<.

Hi Guest, This is complete nonsense!

I think this is getting over analyzed. Obstructions on the earth have always been present, as little as 150~200 yrs ago several parts of NA and the world were covered with trees, now much of that populated area has been cleared but now we have man made structures (ie, buildings / cities, hydro towers and on and on.) (Try to sail a yacht with a tooth pick! ) So the point being is that wind goes up over and around obstacles, everything going on around us is moving with global rotation.

Perhaps I have opened more discussion and it is fun and interesting but the real concern with our long term survival or demise will be what we have done to the earth in the past 200 yrs. You know how we are always concerned about invading species of bugs, wildlife or vegetation on indigenous ecosystems? What do you call humans to the earth than? Look what we have done to North America in a few measly years!

Josh.

Hello PTT,

You make some very interesting points!

This thread is in danger of too much thinking about a subject or phenomenon which does not exist?

IMO you cannot 'extract' power from wind, end of story really. As you say the wind flows over the earth as a consequence of the sun heating the earth and the earth spinning. There is not a finite amount of wind. There may be a certain finite amount of water from a river for instance, but not of wind.

It could be argued that wind mills do not 'extract' wind, but actually make it by the wind mills making eddies which is another wind, but perhaps in a slightly different direction?

Thanks for kinda getting to the point. The Creator made this earth remarkably self-adjusting but that does not negate the consequences of mans actions. "Dust Bowl", mud slides, forest fires, floods, not to mention pollution, man created deserts, etc.

Everything has consequences that really should be analyzed, even over analyzed so rational trade-offs can be made.

Man may have acted in part to allow opportunity for events to effect the landscape but it is a reallocation of the material it doesn't cease to exist.

Hello realist,

I fully understand what you said. However, you should differentiate between areas of man-made-deserts, and the much larger 'natural' deserts.

In the thread discussed IE. Wind, the alteration of the extremely thin 'skin' on earth on which we build and live may redirect the wind. But it does not lessen it.

If a wind turbine was 100% efficient the wind behind it would be 0 knots. This would build pressure in front thus stopping the turbine altogether. This does not happen. Obstructions like trees, buildings and mountains do not stop the wind either, but re-route the wind to a different path. If your scenario was valid it would have already happened with the existing structures on the earth.

"If a wind turbine was 100% efficient the wind behind it would be 0 knots." One might think so, but the pressure would be higher, and it would dissipate sideways. Of course,the flow rate through the turbine would be esentially zero, so efficiency is meaningless. That's why "perfect" is about 50 per cent.

When an obstruction is placed in the path of the wind, (flow) two things happen.

1) some of the energy is "transformed" into another form(s) of energy. (Energy can not be created or destroyed, only changed from one form to another.)

2) the rest of the wind energy will alter its path (flow) and therefore,the consequences will be altered patterns of flow. Because wind also carries moisture, this can affect crops downwind.

In addition to noise, this is another reason for spacing wind generators evenly. Still, if we build cities stretching for say fifty miles along the coast of lake ontario, no one asks what the consequences are...

GA

GA. I think it should also be noted that most likely the energy from the wind turbines is turned into electric energy, which is sent somewhere else and ultimately turned into heat. If we did not harvest that energy from the wind, this same energy would be ultimately be turned into heat by viscous losses. It is just where the energy becomes heat not if.

I cant believe you guys are actually discussing this . Remember the " butterfly effect "

the swirling air caused by the movement of a butterflies wings can cause and effect the weather on the other side of the planet .? What would happen REALIST if we planted propellers everywhere , i shudder to think !

long time ago there were many, many, many, many, many, many, many forests that didn't seem to slow down the winds to much.

The machinery for taking energy from the wind will restore some of the effect that the trees made before they were cut down to develope the land in the down-wind regions.

lol

reminds me of the water spinning in different directions, depending on what hemisphere you live in.

The physics related to scale will make change impossible

If you suck energy from the wind in the northern hemispere it will be balanced by sucking the same amount of energy from the opposite flowing wind in the southern hemisphere.

This all sounds like a bunch of pot heads trying to argue against global physics. Its way beyond most of our present comprehensions.

I have to honestly ask the nay sayers this, What do you propose we power our human civilization with since you don't like fossil fuel or AE systems?

Gerbils on exercise wheels? No wait, that wont do either, thats cruelty to animals.

Your obviously not a true environmentalist or energy conservationist in the real truest form. Being your here using a computer to make these lame ass arguments!

SO honestly answer the question I asked above. What do we use according to you? And be quick about it! According to the nay sayers the collective world wide winds are going to stop any minute now and we are all going to run out of oil so you had better hurry up and respond before the whole internet powers down from global energy depletion!

And no chaos theory answers either. I have my fly swatter set for kill just for when the next butterfly shows up!

"Gerbils on exercise wheels? No wait, that wont do either, thats cruelty to animals."

If you pay them, provide safety equipment, medical insurance, lunch and coffee breaks and vacations there will be no problem.

Jon

For the gerbils or the animal rights nuts?

Its been a few days and still this crazy power hungry internet has yet to power down! Was someones unquestionable environut funded research wrong?

Or did they accidentally carry the zero the wrong way and put the decimal point 5 places to far to the left? Or is it to the right? Which way works in your favor when making up environut numbers???

Obviously the rights nuts.

"power hungry internet"

There is talk of the power hungriest part of internet moving to Iceland for the more economical Geothermal power.

Jon

Reynolds Number + Stokes Law = Myth Busted

...and go easy on the swat

I think there will be less evaporation downwind. Perhaps more bugs because the strong wind makes them uncomfortable and calmer conditions attract them? bees will like it but plants like alders and others that use the wind to distribute their pollen will be disadvantaged. I guess swallows will like it too, more bugs, to eat and not so much mental calculations to catch them! I made a pulser pump (low grade water power to pump water). It would have been swirling rushing turbulent water but instead was calm and very well oxygenated at the exit. I could hardly ever find a stonefly larvae in that stream but at the exit to that pump there were dozens of them! So, what else. Hotter in the day? Because the wind is not blowing quite so hard. I think there will be lots of differences and effects but they will not be documented for several years.

I think a river is analogous to this question. If you place, say, a desk-fan in the surface of a river, a bit a turbulence is created behind the fan and quickly negated by the overwhelming flow of the river. If you place a hundred fans across the river you create a bit more turbulence, but, as the overwhelming flow of water occurs under the fans, the turbulence is soon negated. Like wind turbines, the overwhelming flow of air occurs above the turbines and any terrestrial turbulence is negated by atmospheric airflows above. If you built a turbine, or turbines, which spanned from the surface through the stratosphere, then, like a dam effecting the whole flow of the river, you could dramatically effect downstream flows. I think any surface built turbines would have a negligible effect on overall air currents.

I think the windmills will create less turbulence. They are taking a lot of energy from the wind. slower air = less turbulent flow. sure it might be turbulent round the mill itself but a hundred meters or 200 meters later, I bet the wind is a lot calmer. Has anybody checked? We saw a humming bird hit a glass outdoor windbreak today. (round a patio) It dropped stunned to the ground and flew away after a minute. Lucky for it, there were no cats around. Has anyone statistics for birds killed by glass windows? I think it is like the trees falling in the forest. Perhaps we need a birdquake monitor for window research.

Realist,

Using wind to generate power will provide power that does not pollute, conserves those resources that do pollute, allows removal of dams that interrupted the natural flow and restores habitat to creatures that depend on the natural flow of water and provides energy for pumping and recycling water for agriculture.

The microclimatological effects are less than the artificial methods currently used.

Windmills reduce the force of the wind and the reduce the amount of topsoil blown away by the wind when plowing exposes it in the fields down wind.

Birds that hit windmill blades are sacraficial trainers for the others.

The chicken crossed the road to show the Oppossum that it can be done.

Jon

you've framed the question in such a way as to suggest that one could actually suck "the energy out of the wind". in debate, it's called a "leading question" <LOL> :D

fact is, it's impossible to do so. wind is fluid energy. trying to do so would be tantamount to being able to applying a brake on earth's rotation.

If you don't take energy out of the wind, where does the energy come from?

Pressure, thermal and humidity differentials from all over the world, with the earth's rotation create wind currents.

Well, what is the difference between wind and hydro then? You ARE sucking the energy out of the wind. Just as in a river you are sucking the energy out of the flowing water.

you've framed the question in such a way as to suggest that one could actually suck "the energy out of the wind". in debate, it's called a "leading question" <LOL> :D

fact is, it's impossible to do so. wind is fluid energy. trying to do so would be tantamount to being able to applying a brake on earth's rotation.

please see post 52. my answer would be akin to that.

while both wind and water are fluid, the difference is compressibility. structures on the ground create turbulence at the lower strata, but the miles-high atmosphere which is moving in response to pressure and thermic inducements, with the earth's atmosphere is largely unaffected. the wind's kinetic energy is preserved overall (with a miniscule transmitted to the windmills and other structures).

perhaps a theoretical question can answer the OP's question, as well. what if large air fans were made to blow in one direction (say, East) would they increase the earth's rotation, or trigger some climate change? the answer is still, NO.

for hydro, the water head dictates the amount of kinetic energy that is being transmitted to the impellers. but downstream, the nearly same kinetic energy is recovered by the flowing water (head differential). a case in point is the Agus River in Mindanao, Philippines. along the 33 km length of that river (which starts from Lanao Lake in Marawi City, which has an elevation of 700m ASL), are 7 hydroelectric plants. these series of installations proves that while the water's kinetic energy was transmitted to impellers, the impellers serve only as "baffles that create turbulence", but by virtue of the water's head, the water will practically (not totally) still have lots of energy to proceed with its flow, all the way to the sea.

"these series of installations proves that while the water's kinetic energy was transmitted to impellers, the impellers serve only as "baffles that create turbulence"".

If a turbine in a river takes away 60 or 80% of the energy, it is not a baffle that creates turbulence. Turbulence is energy dependent. Less energy means less turbulence. Imagine the river before the turbines. Swirling rapids, perhaps? Surely not less turbulence.

I cannot imagine how the air flows above a wind turbine due to the turbine slowing the wind throught it but there has to be computer simulations of it and lots of them.

There must be consequences.

If a turbine in a river takes away 60 or 80% of the energy, it is not a baffle that creates turbulence. Turbulence is energy dependent. Less energy means less turbulence. Imagine the river before the turbines. Swirling rapids, perhaps? Surely not less turbulence.

I suppose the turbulence before the dam was similar to that discharged from the turbines.

What's the rub?

"I suppose the turbulence before the dam was similar to that discharged from the turbines.

What's the rub?" Before the dam was built, the water was flowing turbulently to the sea. Now that the dam is built, it is not flowing turbulently because the dam is taking energy from the water. So although the water is flowing at almost exactly the same speed, (volume of water wise) its energy is less. The river conditions are also totally different. When there is wind power everywhere, we can expect different conditions too. I am not saying it is bad. But we should expect it.

The biggest problem I see with windmill power generation is the scattering of dead birds around some installations. I see this as primarily a training problem. After all of the ignorant birds get killed off, there will only be those left that are smart enough to avoid the whirling blades.

Hey! it worked for hawks and eagles. If a bird sees one of them, they either give it a wide berth or attack. In the case of windmills, attacking one will be a self eliminating event so there will be no windmill attackers left after a few generations.

No problem!
TT3

The answer is blowing in the wind

A 100% efficient, horizontal axis windmill can extract a max of 65% of the energy from the wind over it's disc area (Betz law).

In practice, a very good one will extract about 40%, leaving 60%.

The disc area of a very dense wind farm will be a poofteenth of the volume of the atmosphere, and if you try to extract too much a small pressure build up occurs causing some of the wind to bypass around the windmills, further reducing the total amount extracted.

The area below and above the windmills is unaffected, unless extra air is pushed in to bypass the windmills.

It will not be possible to build and install enough windmills to significantly affect the wind at the elevation of the mills, and this is only a small section of the atmosphere.

A massive wind farm, built on a completely uneconomic scale would have less effect than a forest over the same area, and this has happened before without any major problems, just as there were no huge climate problems in most of the world when these areas were cleared for agriculture. (The clearing in some areas may have caused a drying of the climate, eg Australia before and after aborigines cleared most of the rain forest by fire. This probably dried out the entire continent, but this is a special case and has nothing to do with wind turbines).

Consider the opposite of wind extraction, wind generation! What about all of the thousands of Jets taking off in the world? Typically they take off towards the west as the prevailing wind is usually going eastward... Have you ever seen what happens to anything behind the wake of a 747 taking off? (referencing an episode of Myth Busters) The thrust / wind generated from the turbines will pick up a car or bus and send it flying for hundreds of feet like it was a cardboard box. I am pretty sure that a half mile away from the airport it is not windier than any other place in the vicinity. Hey maybe this will counter act all of the wind sucked up by wind turbines!