Is there a limit to wind power?

[mheslep]

Even if we had enough U (which, based on present reserves and present consumption will meet demand until about 2050),

90 years at the current rate of 66,000 tU/yr, using only reserves known today, using only U-235 thermal spectrum reactors. Known U reserves have been increasing for decades. Switch to fast spectrum reactors and the usable fuel supply increases by 100 times. Then there's the ocean content, then there's thorium.

 

[Evanish]

Nuclear power in its present form is not sustainable. Even if we had enough U (which, based on present reserves and present consumption will meet demand until about 2050), the problems with decommissioning and spent fuel have to have simpler solutions. Perhaps the self-contained fast reactors would solve some of those problems and could allow us to use nuclear for another few hundred years. It takes 20 years to develop a nuclear plant. And it takes another 20 to shut one down. Fusion, if it is ever developed and becomes practical, would take even longer to develop and there are still huge shut-down and decommissioning problems and you are still left with radioactive core containment materials that won't be safe to go near for hundreds of years.

Breeder reactors can been done, have been done and should be done more in my opinion. Decommissioning and nuclear waste are small problems compared to something like building a world wide electric grid.

 

[Andrew Mason]

As I explained above, solar and wind as they exist now can not replace coal plants. Natural gas, nuclear, biomass, geothermal, hydro: these all can replace coal and do. Solar and wind can make coal plants run less, but not replace them and close them down. The cost of maintaining both systems side by side is, as shown Germany, very expensive.

I agree, so long as wind and solar are highly variable or intermittent. All I was suggesting is that if we combined all solar and wind into a world-wide grid, that would not necessarily be the case. There is always sun shining and wind blowing somewhere on the earth.

Reliance on biological sources for energy and materials in the past often led to their near extinction: forests, buffalo, whales. While fossil fuels have their own problems and there are reasons enough to limit their use, their introduction allowed forests to regrow where they had been nearly obliterated, e.g. most of the east coast forests of the US in the 19th century. A repeat of the mistakes of the past is comical as far as its currently gone; keep it up though and the comic might become tragic.

Biomass is just a way of storing solar energy. You raise some legitimate concerns. But saying it is difficult does not mean it can't be done. I am not prepared to accept, at least right now, that with careful management, biomass could not be used to generate electrical power. I'm just saying that along with hydro, wind, solar, it could be used to supply all of mankind's electrical energy needs.

AM

 

[Andrew Mason]

Breeder reactors can been done, have been done and should be done more in my opinion. Decommissioning and nuclear waste are small problems compared to something like building a world wide electric grid.

I would like to have seen the US proceed with the Integral Fast Reactor because it does provide a reasonably acceptable solution to the spent fuel problem. It has its own operational challenges - e.g liquid metal cooling. Assuming those are solved, it still leaves the decommissioning problem. But it was canceled and we may never get there.

In the long term, however, we have to use the energy from the sun. It will last as long as there is life on earth. It would be a challenge to make it work but it will work. It is not as if we have to commit huge resources to wind and solar all at once. But if we don't make it an important goal, we will never find the solutions to all the problems it faces.

AM

 

[Evanish]

I would like to have seen the US proceed with the Integral Fast Reactor because it does provide a reasonably acceptable solution to the spent fuel problem. It has its own operational challenges - e.g liquid metal cooling. Assuming those are solved, it still leaves the decomissioning problem. But it was canceled and we may never get there.

In the long term, however, we have to use the energy from the sun. It will last as long as there is life on earth. It would be a challenge to make it work but it will work. It is not as if we have to commit huge resources to wind and solar all at once. But if we don't make it an important goal, we will never find the solutions to all the problems it faces.

The breeder reactors that we can be built today are good enough in my opinion sodium coolant and all. We should start building them now. We likely won't, but we should in my opinion. In the long run breeder reactors could power civilization for millions if not billions of years. That seems long term enough to me. I've spent a good number of years reading about this subject. It has not left me with much confidence in wind and solar. I'd feel much safer if we were building nuclear instead, but I seem to be outvoted (in western society at least) so I guess I'll just have to wait and see. I am a bit curious why you think decommissioning is such a big issue.

 

[Andrew Mason]

The breeder reactors that we can be built today are good enough in my opinion sodium coolant and all. We should start building them now. We likely won't, but we should in my opinion. In the long run breeder reactors could power civilization for millions if not billions of years. That seems long term enough to me. I've spent a good number of years reading about this subject. It has not left me with much confidence in wind and solar. I'd feel much safer if we were building nuclear instead, but I seem to be outvoted (in western society at least) so I guess I'll just have to wait and see. I am a bit curious why you think decommissioning is such a big issue.

I'm not sure about your "millions" if not "billions" of years. The fuel consumption of a faster breeder reactor, assuming it can reprocess and eventually use all of its Uranium fuel, is about 1/100th that of current light water reactors. So you seem to be saying that nuclear power using current reactors would work for 10,000 to 10,000,000 years.

Decommissioning is a problem for sustainability. It is very expensive and difficult to dismantle and safely keep the core materials isolated from living creatures for the few thousand years that is required. You end up having to encase everything in concrete and seal off the site forever. We don't know all the details of decommissioning most of the current nuclear plants let alone the cost and feasibility of decommissioning one 50 years from now.

AM

 

[mheslep]

You end up having to encase everything in concrete and seal off the site forever.

Dozens of US nuclear reactors have been decommissioned, paid for by the industry. Here's the Maine Yankee plant before closing in 1996:

and after (overhead):

http://www.3yankees.com/images/thumb_002.jpg

 

[Evanish]

I'm not sure about your "millions" if not "billions" of years. The fuel consumption of a faster breeder reactor, assuming it can reprocess and eventually use all of its Uranium fuel, is about 1/100th that of current light water reactors. So you seem to be saying that nuclear power using current reactors would work for 10,000 to 10,000,000 years.

The amount of Uranium that can be recovered economically increases greatly when breeder reactors are used. Right now the lowest grade ore used has around 100 part per million uranium, but if we had breeder reactors that are one hundred times more efficient then current light water reactors we could go after ores that are 1 part per million. The Earth continental crust has http://www.world-nuclear.org/info/Nuclear-Fuel-Cycle/Uranium-Resources/Supply-of-Uranium/ on average. Pretty much everything is potential ore when breeder reactors are used. There is something like 40 trillion tons of uranium in the Earth's crust. Recovering just a fraction of that, and utilizing breeder reactors, would supply billions of people with a decent life till things heat up and life on the planet ends. We don't even necessary need to mine it ourselves since it's water soluble. The oceans are full of uranium that could be recovered if we were using breeder reactors, and rivers wash more uranium into the ocean at a rate of 32,000 tons (page 165). More then enough to meet all the worlds energy needs. It's awe inspiring really. It's a shame most people don't seem to be aware of it.

 

[rootone]

Regarding wind power, yes there is a theoretical limit, since the total amount of energy involved in driving the winds is not infinite.
However the proportion of that energy extracted by current wind farms is insignificantly small.
Even if we were to cover the entire surface of Earth with wind farms we wouldn't get anywhere near to approaching the theoretical limit

 

[OmCheeto]

Regarding wind power, yes there is a theoretical limit, since the total amount of energy involved in driving the winds is not infinite.
However the proportion of that energy extracted by current wind farms is insignificantly small.
Even if we were to cover the entire surface of Earth with wind farms we wouldn't get anywhere near to approaching the theoretical limit

I agree. I've been watching the wind power density above my house over the last few days, and my rough estimates are that there is somewhere between 1 billion and 20 billion times as much power in the wind as humans consume.

x axis is elevation in meters
y axis is watts/meter²

low power day (3/17/2015 16:00 PDT)​

high power day (3/15/2015 13:00 PDT)​

Numbers are from over my house 45.6°N 122.6°W
Data collected from earth.
Surface area of Earth: 510 trillion m²
Earthling annual energy consumption: 5 x 10²⁰ joules in 2010

On a somewhat humorous, very coincidental side-note; at about the same time I posted the following the other day:

Though, a 10km tall, 440 km long scaffolding, strikes me as a bit of an economic/engineering problem. Not to mention, the wind is constantly shifting.

A wind storm hit my city, and knocked down a 30 meter tall scaffolding.
I was like; "Yup. We can't even build a 30 meter tall scaffold. Good luck with one 10,000 meters tall."

 

[Buckleymanor]

Regarding wind power, yes there is a theoretical limit, since the total amount of energy involved in driving the winds is not infinite.
However the proportion of that energy extracted by current wind farms is insignificantly small.
Even if we were to cover the entire surface of Earth with wind farms we wouldn't get anywhere near to approaching the theoretical limit

Should imagine you might approach some kind of tipping point. If only from the reduction in the Earth's rotational speed, building all them windmills some sixty feet in hight covering the entire surface will surely affect the angular momentum of the planet.

 

[anorlunda]

Should imagine you might approach some kind of tipping point. If only from the reduction in the Earth's rotational speed, building all them windmills some sixty feet in hight covering the entire surface will surely affect the angular momentum of the planet.

Not if half the wind component is East and half West. East-west and north-south components of wind approximately cancel.

 

[Buckleymanor]

Not if half the wind component is East and half West. East-west and north-south components of wind approximately cancel.

Nothing much to do with the wind component. The construction of the windmills is all that is required to effect the angular momentum.Hold your arms out when you spin and you go slower.

 

[rootone]

I doubt if would affect the rate of the Earth's rotation in any noticeable amount though.
Probably it would have less effect then that does the tidal effect of the moon, which is already very gradually slowing the spin.
A sixty feet tower is trivial in mass compared to the bulk of the Earth, and even thousands of them would not add up to making a lot of difference.

 

[Buckleymanor]

The post quoted mentioned covering the entire surface of the Earth with wind farms. I doubt that would add up to thousands of wind mills.There are limits to any system and the effects they produce.I agree a few thousand windmills would not make much difference but a few million windfarms might.

 

[rootone]

Well obviously it's not a realistic proposition that the entire surface could be covered with windmills,
but in terms of the difference it could make to angular momentum in principal, we would need to consider the total mass of construction material this would involve and what difference it would make to angular momentum when displaced by 60 feet.
Compare this then to effect of the mass of the moon displaced by 384,400 km (1,261,154 feet).

 

[Vespa71]

Windmills and solar are actual contributions to future electricity solutions. They are much smaller, and require a vast reduction in total consumption, if they'ra going to replace fossile and nuclear. Hydro will buffer solar and wind on the grid. Artificial hydro-drops will possibly buffer some.

 

[Andrew Mason]

Well obviously it's not a realistic proposition that the entire surface could be covered with windmills,
but in terms of the difference it could make to angular momentum in principal, we would need to consider the total mass of construction material this would involve and what difference it would make to angular momentum when displaced by 60 feet.

Perhaps you meant angular speed of the Earth rather than angular momentum?

Compare this then to effect of the mass of the moon displaced by 384,400 km (1,261,154 feet).

I think you meant: 1,261,154,856 feet.

AM

 

[rootone]

Yes the latter was probably just a pasting error, (I used an online calculator).
I referred to angular momentum because this was the term used in the preceding discussion, but yes angular velocity would have been the correct term.
My point basically was that I doubt it would be much affected by construction of windmills even in enormous numbers, and that the existence of the moon probably has an effect which is orders of magnitude greater, and even that is too small to make any difference over timescales in the order of a human life span.

 

[Buckleymanor]

Yes the latter was probably just a pasting error, (I used an online calculator).
I referred to angular momentum because this was the term used in the preceding discussion, but yes angular velocity would have been the correct term.
My point basically was that I doubt it would be much affected by construction of windmills even in enormous numbers, and that the existence of the moon probably has an effect which is orders of magnitude greater, and even that is too small to make any difference over timescales in the order of a human life span.

You are probably wrong about the consiquenceis if windmills were constructed in enormous numbers if you consider that the construction of dams in the northern hemisphere allready has a measurable effect on the angular speed of the earth.

 

[rootone]

I'm surprised to hear that the building of hydroelectric dams has had a measurable effect on the Earth's speed of rotation.
However what does 'measurable' mean?, has it actually been measured?, and what are the numbers?
Do you have a link to this kind of research?.
Or even theoretical numbers based on a reliable source might persuade me.
What I need to be persuaded of is that large scale construction projects on or near the surface of Earth could alter the rate of Earth's rotation on a scale comparable to that which the Moon produces.

 

[Buckleymanor]

I'm surprised to hear that the building of hydroelectric dams has had a measurable effect on the Earth's speed of rotation.
However what does 'measurable' mean?, has it actually been measured?, and what are the numbers?
Do you have a link to this kind of research?.
Or even theoretical numbers based on a reliable source might persuade me.
What I need to be persuaded of is that large scale construction projects on or near the surface of Earth could alter the rate of Earth's rotation on a scale comparable to that which the Moon produces.

Here is a linkhttp://cel.webofknowledge.com/InboundService.do?product=CEL&SID=Y2BdCthPKMeqDIKaF7B&UT=WOS%3AA1995TM72800025&SrcApp=Highwire&action=retrieve&Init=Yes&SrcAuth=Highwire&Func=Frame&customersID=Highwire&IsProductCode=Yes&mode=FullRecord
If you have a google there is quite a lot of info on the subject.

 

[rootone]

It's a pity that I can't see the details without having to subscribe, but based on the abstract, I don't have a problem to accept that large scale construction could cause significant environmental impact.
That is something which I have never doubted, and for example changes to polar drift was mentioned as being measurable.
Bear in mind that I am not seriously proposing covering the entire surface with windmills or anything else.
Simply doubting that the amount of mass displacement involved would alter the Earth's rotation to a degree comparable to which the moon alters it.

 

[Andrew Mason]

You are probably wrong about the consiquenceis if windmills were constructed in enormous numbers if you consider that the construction of dams in the northern hemisphere allready has a measurable effect on the angular speed of the earth.

Are you referring to the .06 microseconds that the Three Gorges Chinese Hydro-electric project is calculated to have increased the length of Earth's day? I am not aware that this has actually been measured.

This is the calculated change in the Earth's angular speed due to raising 39 trillion Tonnes of water 175 metres. How many 60 m. 100 Tonne windmills do you reckon it would take to have a similar effect, assuming they were placed within 30 degrees of the equator? It would have to be at least a few trillion windmills or about 1,000 windmills for each person on the earth.

AM

 

[Skeptik22]

Given the complexity of the problem, I'd say that "taming hurricanes with strategically located wind farms", is about as doable, as herding cats.

Maybe if one could rely on the butterfly effect .. and trap the butterfly in Tiananmen Square before it has time to beat it's wings ...

 

[Skeptik22]

I'm sure lots of studies have been done. I can't find the webpage I looked at yesterday stating that one study says there would be little effect, and another study says there would be disastrous effects. Everyone has their model.

Here's one from MIT done almost exactly 5 years ago:

Odd that there are not "lots" of studies referenced in this thread...

In fact I have found very few ... which is really what prompted the question in the first place.

 

[OmCheeto]

Odd that there are not "lots" of studies referenced in this thread...

In fact I have found very few ... which is really what prompted the question in the first place.

There are probably lots of reasons for the lack of "Windmill effects on Global and Local Climates".

1. Climate modeling is complicated enough without additional variables.

2. No one had to worry about it before now.

HISTORY OF WIND ENERGY

• 1990–More than 2,200 MW of wind energy capacity is installed around California, creating more than half of the world’s capacity for wind power.
• 1992–The Energy Policy Act authorizes a production tax credit of 1.5 cents per kilowatt hour (kWh) of wind-power-generated electricity and re-establishes a focus on renewable energy use.
• 2000–The cost of wind-power-generated electricity is between 4 to 6 cents per kWh.
• 2004–The cost of electricity from wind-generated sources drops to 3 to 4 cents per kWh.
• 2007–Wind produces enough energy to power roughly 2.5 million homes and makes up 5% of the renewable energy used in the United States.
• 2008–The U.S. Department of Energy publishes their 20% Wind Energy by 2030 initiative.
• 2012–The amount of wind energy produced in the United States reaches the point of being able to power 15 million homes and becomes the number-one source of renewable electricity.
• 2013–Jose Zayas, Wind Program Director, announces Wind Vision, a new initiative to revist the findings of the 2008 report.
• 2015–The Wind Vision Report is released showing that 35% wind energy is possible by 2050.

I'm not even going to bother calculating what fraction of energy wind supplied in 1990.
BP conveniently collected some data for us: http://www.bp.com/content/dam/bp/excel/Energy-Economics/statistical-review-2014/BP-Statistical_Review_of_world_energy_2014_workbook.xlsx

y axis is in megawatts​

and didn't bother either. As it looks like zero, compared to today.3. There are worse things in life than minor localized climate change.

I'm sure there are more. You should learn to use the PF search engine. There are scores of threads on this topic.
Can this satisfy the world's energy needs? High-altitude wind power
etc, etc, etc.

 

[Skeptik22]

Just because a question is difficult doesn't mean we should not ask it .. or try to find an answer ...

The charts of installed windfarm "capacity" are readily available and have been referred to in the thread at least a couple of time now.

What is not so obvious is whether anyone has tried to correlate changes in climatic patterns with this existing data ...

Could one show a relationship between say.. increased occurrences of extreme weather events ... with the increase in windfarm activity.

Probably not, as OMCheeto suggests it is too difficult ...

so ...

at what point would any effect be detectable?There seems to be an assumption in the thread that any changes will be detrimental .. this may not be so ... it will depend on one's frame of reference...

 

[OmCheeto]

...
at what point would any effect be detectable?
...

Finally! A question.

It will be detected, when you see a blade of grass move.

 

[Skeptik22]

I think A.T. gave the correct answer in post #4.
If there was no windmill, 100% of the wind energy must eventually dissapate in the form of heat.

When there is a windmill, we produce electricity, but 100% of that energy also eventually dissapates as heat.

Unless the locations and timing of the two kinds of dissipation are widely different on a global/historic scale, the net effect on climate must be zero regardless of how much wind power is used.

Is this "proof" of climate change?

Fossil fuels are effectively the conversion of incoming solar energy to chemical.. over the whole earth.. over a long period of time ... Industrialisation has resulted in this being converted back to heat over a short period .. therefore it result in climate change ...

Sorry .. not really on topic ...

 

[Andrew Mason]

Is this "proof" of climate change?

Fossil fuels are effectively the conversion of incoming solar energy to chemical.. over the whole earth.. over a long period of time ... Industrialisation has resulted in this being converted back to heat over a short period .. therefore it result in climate change ...

...Interesting question. Let's work it out.

1. Human energy consumption heats only the atmosphere:
It takes 1KJ to raise the temperature of 1Kg of air by one Kelvin. The earth's atmosphere has a total mass of 5 x 10¹⁸. So to raise the temperature of the Earth's atmosphere (assuming no increased radiation into space and no heating of the Earth surface) would require 5 x 10¹⁸KJ of energy.

Combustion of one Kg of petroleum releases about 5 x 10⁴ KJ of energy. So raising the temperature of the atmosphere by one Kelvin/Celsius degree would require burning about 10¹⁴ Kg of petroleum or about 3 x 10¹² barrels of oil and retaining all that heat in the atmosphere. The entire world burns a bit less than 10⁸ barrels a day or about 3 x 10¹⁰ Kg per year. That is enough to raise atmospheric temperature by 1/100th of a degree C/K in a year if the heat was retained entirely in the atmosphere.

Since the world consumes about 2 x 10⁵ terrawatt-hours per year and one terrawatt-hour = 3.6 x 10¹² KJ, the world uses about 7 x 10¹⁷ KJ of energy annually. That is enough to raise the temperature of the Earth's atmosphere by about 1/10th of a degree C/K if all of that energy was produced from a source other than the sun (ie. nuclear or fossil fuels).

2. Comparison to total Insolation/heat radiated

Of course, we know that the Earth and surface water/oceans take up heat from the atmosphere and the Earth's atmosphere radiates energy into space. We know that without heat being added by non-solar sources, the Earth is in a state of thermal equilibrium so it radiates as much energy as it receives from the sun. So let's compare the amount of heat added to the Earth by human non-solar energy to the total amount of heat added by the sun.

Total solar insolation of 1.3 KW/m² over the cross-sectional area of the Earth 1.3 x 10¹⁴m² = 1.7 x 10¹⁴ KJ/sec. Since there are 3600x24x365 = 3.15 x 10⁷ seconds in a year, this amounts to about 5 x 10²¹KJ per year, or about 10,000 times as much energy as humans contribute from all sources and 100,000 times as much as the heat contributed from burning petroleum.

Conclusion

While the heat from non-solar energy sources used by humans is significant, it represents a tiny, insignificant fraction of the solar energy received by the Earth and which is radiated into space.

AM

 

[mheslep]

...raise atmospheric temperature by 1/100th of a degree C/K in a year if the heat was retained entirely in the atmosphere.

Right, if the atmosphere was inside a giant insulated oven with the door closed. It is not. The oven door is open. Received or generated heat is constantly being transferred into space, and the surface constantly seeking its black body temperature of -18 deg C (albedo included). The way to raise the temperature then of such a would be cold world is to effectively close the oven door, i.e. add some kind of insulating mechanism which slows heat transfer: water vapor, methane, carbon dioxide ...

 

[russ_watters]

Is this "proof" of climate change?

Fossil fuels are effectively the conversion of incoming solar energy to chemical.. over the whole earth.. over a long period of time ... Industrialisation has resulted in this being converted back to heat over a short period .. therefore it result in climate change ...

Sorry .. not really on topic ...

That's not what climate change is, and yes, let's keep it on topic.

 

[Evanish]

Earthling annual energy consumption: 5 x 10²⁰ joules in 2010

This number seems way to low. From here I get that the world used 13,217 Mtoe In 2013 . 13,217 Mtoe http://www.iea.org/statistics/resources/unitconverter/ 153,714 Terawatt hours. There are 8,765.81 hours in a year. From this we can reason that human civilization is run on around 17.5 Terawatts. That is a lot of power, and it is increasing every year as people all around the world escape poverty.

There is a lot of kinetic energy in the Earth's winds, but we can only sustainable harness so much of it. According to one of my http://www.theoildrum.com/node/8322 the total kinetic energy dissipation in the atmosphere vary from 340 TW to 3600 TW. So maybe if we could harness between 5 and .5 percent of that we could power civilization with wind, but doing so would be extremely difficult for a number of reasons. Also, you really can't say for sure that it wouldn't effect the weather negatively. Fluid dynamics is incredibly complex, and we are talking about major changes to a very large and complex system. Some people on the thread seem a little too dismissive of any potential problems.

 

[OmCheeto]

Earthling annual energy consumption: 5E20 joules in 2010

This number seems way to low. From here I get that the world used 13,217 Mtoe In 2013 . 13,217 Mtoe http://www.iea.org/statistics/resources/unitconverter/ 153,714 Terawatt hours.

per google calculator:
153 714 terawatt hours = 5.5E20 joules

There are 8,765.81 hours in a year. From this we can reason that human civilization is run on around 17.5 Terawatts. That is a lot of power, and it is increasing every year as people all around the world escape poverty.

There is a lot of kinetic energy in the Earth's winds, but we can only sustainable harness so much of it. According to one of my http://www.theoildrum.com/node/8322 the total kinetic energy dissipation in the atmosphere vary from 340 TW to 3600 TW. So maybe if we could harness between 5 and .5 percent of that we could power civilization with wind, but doing so would be extremely difficult for a number of reasons. Also, you really can't say for sure that it wouldn't effect the weather negatively. Fluid dynamics is incredibly complex, and we are talking about major changes to a very large and complex system. Some people on the thread seem a little too dismissive of any potential problems.

There are always problems. But one has to balance whether one wants to live in a modern, sustainable world, or, become a worm eater. (Shroom eater, if one is vegan).

 

[Evanish]

per google calculator:
153 714 terawatt hours = 5.5E20 joules

It seems my "way to low" was overstated.

There are always problems. But one has to balance whether one wants to live in a modern, sustainable world, or, become a worm eater. (Shroom eater, if one is vegan).

I want to live in a modern sustainable world powered predominately by nuclear power. The problems needing to be overcome for a nuclear world seem far more manageable to me.

 

[OmCheeto]

...
I want to live in a modern sustainable world powered predominately by nuclear power. The problems needing to be overcome for a nuclear world seem far more manageable to me.

That's why I joined the navy back in 1977! They said I could be a "nuke". And I became a "nuke". Then stuff happened. Then I decided it was not a good idea to put all my stones in one pot, or something like that.

Wind energy is one of many available sources. I've learned to diversify my energy investments.

Btw, have you seen this thread? "YOU! Fix the US Energy Crisis".

It's a lot of fun.

 

[Skeptik22]

This seems to have reached the level of a bar-room argument .. more about one's favoured source of power for one's toys .. rather than the original question .. and I am probably as guilty as the next person.

Given that this seems to be quite a tricky question .. one would have thought there would be more academic focus on trying to produce an answer.

The one paper which was quoted earlier in the discussion .. which actually attempted to put on number on the total power availability ...had lots of caveats .. is that what physics has come to .. making an educated guess and including a raft of get out clauses .. to prevent further debate?

 

[A.T.]

Given that this seems to be quite a tricky question .. one would have thought there would be more academic focus on trying to produce an answer.

This is definitely not how academic priorities are being set.

The one paper which was quoted earlier in the discussion .. which actually attempted to put on number on the total power availability ...had lots of caveats .. is that what physics has come to .. making an educated guess and including a raft of get out clauses ..

This is what physics always was: making predictions based on assumptions, which might be more or less certain.

 

[OmCheeto]

.. rather than the original question ..

Always a good idea to go back to the OP.

1. Is there a limit to the amount of energy which can be extracted from the wind?
2. There are a huge number of windfarms springing up around the world..
2.5 all taking energy from the wind.
3. The assumption seems to be that this is limitless and "free".
4. Clearly this is not possible.
5. The question is (I think) - how will the transfer of energy (from the wind) manifest itself on the climate,
5.5 and could the impact be measured?
6. The only research I have seen to date, relates to finding the "best" location for a windmill,
6.5 and some on the effect on local weather conditions.

{numbered for clarity}

My answers:

1. Yes
2. Opinion. Huge, for me, would be if wind farms extended for thousands of kilometers, all over the world. (Mostly along the coasts.)
2.5 Yes
3. Ha! Hahahahaha!
4. Ok. Sorry about laughing at your assumption. Yes, I mean no, you are correct.
5. This strikes me as kind of a rhetorical question. Perhaps it will manifest itself in good ways, and bad ways.
5.5 Everything can be measured.
6. Makes sense to me.
6.5 I would love to see wind farms put up to my east. Those winds are dreadfully bad in the fall. But I just discovered that one of the world's largest wind farms was put up, just there, and I haven't really noticed a change. Not surprising to me. There's still a lot of untapped energy up there.

This seems to have reached the level of a bar-room argument .. more about one's favoured source of power for one's toys

I hope I haven't given such an impression. I've been adverse to "one trick ponies" for quite some time.

One day, I was setting up my solar powered water pumping system to water down the sand volleyball courts, as they get dreadfully hot in the summer, and burn our feet, when someone walked by and said to me; "Wind power is better".
I thought to myself; "What an imbecile. If it were that windy, no one would be out here playing volleyball!"

On another occasion, someone told me that the only way to make cars more energy efficient, was to make them lighter.
I thought to myself; "What an imbecile. Electric cars are much more energy efficient, and they are heavier!"

Now, the above two examples, might peg me as some "solar" lunatic. Quite the contrary. Do you have any idea how much effort, not to mention the room, it takes to haul 150 watts of solar panels and 400 feet of garden hose out to the river in a 14 foot boat every day? No. Of course not. Only I do. It's a pain in the butt. And that's why I devised a wave powered volleyball court watering system. It would run 24/7! There are always ships running up and down the river making waves. Not to mention the wind generated waves.

But then, I'm sure you'd show up, and ask; "Have you done a study, on the global climate effects, of your wave machine"?
And I'd say; "No. It's not worth my time. Though, I'm sure it has had an effect on the shifting of the sand on the beach, but not enough to worry about".

Ditto with your wind question. We've so far extracted too little energy, to have an effect, IMHO.