Darnok

Large-scale wind energy slows down winds and reduces turbine efficiencies

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This is already a pretty well-known and intuitive effect. What these guys have done is just to quantify it. Interesting research, but reducing average windspeeds downwind of a turbine doesn't make them less clean or safe, aside from the fact that a less efficient turbine has a greater impact per kW in terms of rare earth metals etc. than a more efficient one.

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"The authors calculated that when wind energy is used at its maximum potential in a given region, each turbine in the presence of many other turbines generates on average only about 20% of the electricity compared to what an isolated turbine would generate."

"Dr. Axel Kleidon, group leader at Max-Planck-Institute for Biogeochemistry, admits that these scenarios of wind energy are hypothetical. Yet, he sees the results as highly relevant for the future expansion of wind energy."

I find it hasty to say "clean energy is not so clean and not so safe for environment". At most the result means that wind turbines should not be placed right next to one another in huge numbers, which makes intuitive sense both environmentally and financially.

To those who post after us: the OP did make a sweeping and provocative claim, but please let others be the ones who lapse into insults. Thank you.

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I thought it was obvious that a wind turbine screws with the air behind it, making that space not the most efficient place to use another turbine in?

It's still better than coal and plastic trash people throw into their chimneys.

Edited by Veeltch

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18 minutes ago, peadar1987 said:

This is already a pretty well-known and intuitive effect. What these guys have done is just to quantify it. Interesting research, but reducing average windspeeds downwind of a turbine doesn't make them less clean or safe, aside from the fact that a less efficient turbine has a greater impact per kW in terms of rare earth metals etc. than a more efficient one.

It changes micro-climate in factor of a lot larger than CO2!

 

5 minutes ago, SchweinAero said:

I find it hasty to say "clean energy is not so clean and not so safe for environment". At most the result means that wind turbines should not be placed right next to one another in huge numbers, which makes intuitive sense both environmentally and financially.

To those who post after us: the OP did make a sweeping and provocative claim, but please let others be the ones who lapse into insults. Thank you.

They are not safe, since they destroy micro-climate near wind turbines, what is affecting water vapour and this gas is much more dangerous than 0.0003% of CO2 produced by our industry :)

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1 minute ago, Veeltch said:

I thought it was obvious that a wind turbine screws with the air behind it, making that space not the most efficient place to use another turbine in?

Yeah, the immediate wake of wind turbines is pretty well-understood, you definitely don't want another turbine within about 5 rotor diameters of another, but this is more about the longer-term effects after the wake itself has dissipated, but still has slowed down the bulk fluid because of shear and turbulence.

Just now, Darnok said:

It changes micro-climate in factor of a lot larger than CO2!

 

They are not safe, since they destroy micro-climate near wind turbines, what is affecting water vapour and this gas is much more dangerous than 0.0003% of CO2 produced by our industry :)

Have you got a citation for this?

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4 minutes ago, Darnok said:

It changes micro-climate in factor of a lot larger than CO2!

 

They are not safe, since they destroy micro-climate near wind turbines, what is affecting water vapour and this gas is much more dangerous than 0.0003% of CO2 produced by our industry :)

I'd like to hear the details of this mechanism. Is it a significant effect per unit of energy in comparison to other energy sources? Relevant citations wouldn't hurt either, if it's not too much trouble.

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Unless someone has data on how a persistent reduction in wind in a given ecosystem affects the life there, you basically cannot say one way or another what the effect might be. For people who want policies based on "just in case..." this seems pretty odd.

I suppose you could look at prevailing wind directions, and see if there are any critters or plants that prefer the open vs lee sides of rocks.

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Browsing for Dr. Lee Miller i get the feeling that this is a "sponsored research". He doesn't even state his climate model, it seems like it was created for that purpose.

There already has been more serious work on the impact of turbines on local (!) windsystems. Global atmospheric circulation is driven by the the arrangement of continents, sea currents, large scale solar insolation, atmospheric composition ... these things. Even mountain ranges have "only" sub-continental impact on gc.

With my (limited) knowledge of earth science i'd say: nonsense.

Until proven wrong of course :-)

Edit: if course, the wind behind the turbine is different than in front of it, but the amount of energy taken out even by a large scale windpark (northsea comes to mind) is neglectible compared to what is available. And polluting the atmosphere with even more greenhouse gases or radiation is the ... second best solution, to say the least ;-)

 

Edited by Green Baron

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Quote

But the researchers found that in the predawn hours, when the atmosphere is less turbulent, a large windmill array could influence the local climate, raising temperatures by about 2 degrees Celsius (about 4 Fahrenheit) for several hours. The rotating blades could also redirect high-speed winds down to the Earth’s surface, boosting evaporation of soil moisture.

https://www.masterresource.org/climate-sensitivity-climate-change/nano-climate-change-an-issue-for-industrial-wind/

So we have few hours per day higher temperature by ~2C I only hope they calculated that into global warming models and average temperature readings. Change in 2C for few hours per day affect average temperature by about 0.4C, which is seen as inevitable disaster by global warming fanatics caused by CO2 :)

 

https://www.theguardian.com/environment/2012/apr/29/wind-farms-night-temperatures-study

http://www.ucsusa.org/clean-energy/renewable-energy/environmental-impacts-wind-power#.WCsaK7VVK1E

 

Really guys you should try to find something... even on wiki you have

https://en.wikipedia.org/wiki/Environmental_impact_of_wind_power

Quote

Wind farms may affect weather in their immediate vicinity. This turbulence from spinning wind turbine rotors increases vertical mixing of heat and water vapor that affects the meteorological conditions downwind, including rainfall.[107] Overall, wind farms lead to a slight warming at night and a slight cooling during the day time.

Which means turbines are changing farm-land into deserts, since such change in temperature levels also affects rain levels over the area.

 

Edited by Darnok

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@Darnok: weather and climate are different things.

10 minutes ago, Darnok said:

Which means turbines are changing farm-land into deserts, since such change in temperature levels also affects rain levels over the area.

 

No.

The slight temp differences refer to a few .1 of degrees a few 100m behind the turbines. Data from social media is grossly misleading (disinformation), go to the sources ;-)

 

Edited by Green Baron

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2 minutes ago, tater said:

Unless someone has data on how a persistent reduction in wind in a given ecosystem affects the life there, you basically cannot say one way or another what the effect might be. For people who want policies based on "just in case..." this seems pretty odd.

I suppose you could look at prevailing wind directions, and see if there are any critters or plants that prefer the open vs lee sides of rocks.

I've had a quick dig...

Wind turbines cause mixing of the air in their immediate vicinity. This causes warmer days and colder nights, on average. Modelling was carried out to estimate the long-term effects of large amounts of wind turbines. They predicted very small effects in regional climate, mainly caused by changes in wind direction, amounting to perhaps a few tenths of a degree in the most affected places, and up to a 5% change in precipitation.

1 minute ago, Darnok said:

Your first and second resources only talk about the impact within the footprint and a few km downwind of the wind farm. It is also worth noting that global temperatures are largely unaffected. The increase in ground level temperature due to mixing is offset by a decrease in temperature up to a few hundred metres above the wind farm.

Your third resource doesn't mention turbulence and mixing effects at all, it's all things like bird and bat kills, and lifecycle carbon emissions.

Your wiki link contains this: " Wind power has a negligible effect on global mean surface temperature, and it would deliver "enormous global benefits by reducing emissions of CO2 and air pollutants". Another peer-reviewed study suggested that using wind turbines to meet 10 percent of global energy demand in 2100 could actually have a warming effect, causing temperatures to rise by 1 °C (1.8 °F) in the regions on land where the wind farms are installed, including a smaller increase in areas beyond those regions. This is due to the effect of wind turbines on both horizontal and vertical atmospheric circulation. Whilst turbines installed in water would have a cooling effect, the net impact on global surface temperatures would be an increase of 0.15 °C (0.27 °F) "

So more mixing effects that only have an effect right at the surface, only having a tiny effect on overall temperatures. There's no evidence that I can find suggesting that wind power is "changing farmland into desert", for example.

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49 minutes ago, Darnok said:

Thank you for the sources. Looks like the global effect is very small then compared to, say, the carbon emissions of coal powerplants.

According to the source on the Wikipedia page you linked, the existing temperature change is on the order of .5 degrees Celsius. @Green Baron has said nothing to contradict the evidence.

Edited by Red Iron Crown
Removed quote

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Nope, wikipedia, newspapers and internet news magazines are not sources. The content is in no way controlled and endangered to serve the purpose to transport a message. So that should be taken with salt ;-)

Dr. Miller mixes weather and climate and seems to use a climate model that suits his assumptions. He is, as i read, not a climatologist but a neurobiologist and i couldn't find any other publications of him on the subject, so i find it hard to take it serious.

Climatology is a very complex field of earth science and from time to time driven by politics because much of it can be subject to interpretation. If you just post a link to a text that contradicts a main-stream view you should expect responses like mine ... :-)

I'm not that much into local climate or weather phenomina since these are very difficult to model and put into numbers. In fact, measurements are often uncomparable since on a day with more sun you'll have completely (local) different temps/humidity/thermal winds than on a cloudy day. Regional weather changes or overlays the local conditions, seasons do and large scale circulations as well.

But, as a peace offer, i change my response from "nonsense" to "i do not believe it".

Peace ?

gb

 

Edited by Red Iron Crown
Removed reference to removed post.

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Thread tidied up a bit. If you cannot make arguments without resorting to personal attacks please don't bother posting.

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For anyone wanting a peer-reviewed source, there is a fairly extensive review paper here:

http://www.sciencedirect.com/science/article/pii/S1364032115016457

Might be behind a paywall for some, but conclusions are basically the same as those outlined above. Some significant local effects, warming of up to 1 degree within the footprint of the windfarm and immediately downwind. Some smaller effects elsewhere due to changing weather patterns. Possible impacts on agriculture and the local ecosystem, again within the footprint of the wind farm. No implications of turning farmland into desert or anything, although it does stress the need for more research.
 

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@Darnok,

i probably didn't hit the right tone in my responses, sorry if i upset you.

I must admit that posts like (sloppy) "look i found out that climate care isn't as important as we all should believe" do in fact provoke me, that is my excuse. Nevertheless, i didn't mean anything personal, i'm not your enemy.

But i'm not a teacher as well, searching for publications on a special subject like the above takes a lot of time that i do not always want to invest. That might be the reason why you had the impression i was posting just an opinion. Of course, your impression was correct. Touché.

:-)

gb

Edited by Green Baron

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1 hour ago, peadar1987 said:

I've had a quick dig...

Wind turbines cause mixing of the air in their immediate vicinity. This causes warmer days and colder nights, on average. Modelling was carried out to estimate the long-term effects of large amounts of wind turbines. They predicted very small effects in regional climate, mainly caused by changes in wind direction, amounting to perhaps a few tenths of a degree in the most affected places, and up to a 5% change in precipitation.

That's pretty substantial, actually. Unfortunately there are wind plants here in New Mexico (I can now see some out near Mt Taylor, what an eyesore on a beautiful landscape, luckily it's about 80km from my house, so they are tiny---still an eyesore with their blinking lights, though). Anyway, we only get about 25cm of rain a year, and 5% matters. The desert is a harsh environment, and small changes matter.

Primary solar is better than secondary (wind).

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10 minutes ago, tater said:

 

Primary solar is better than secondary (wind).

Yes. Though i believe that on- or offshore windparks could provide a good part in renewable energies ...

 

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Just now, Green Baron said:

Yes. Though i believe that on- or offshore windparks could provide a good part in renewable energies ...

Yeah, except the people pushing wind in the US have beach houses, they want the eyesores in someone else's neighborhood.

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5 minutes ago, tater said:

That's pretty substantial, actually. Unfortunately there are wind plants here in New Mexico (I can now see some out near Mt Taylor, what an eyesore on a beautiful landscape, luckily it's about 80km from my house, so they are tiny---still an eyesore with their blinking lights, though). Anyway, we only get about 25cm of rain a year, and 5% matters. The desert is a harsh environment, and small changes matter.

Primary solar is better than secondary (wind).

Well the actual source said "from 0 to 5%". Implying 5% is the absolute upper limit, and most places would get far less. Solar is not without its impacts as well, I think the best form of renewables will depend very strongly on the exact area. The researchers have noted that in mountainous or wooded areas the impact of wind turbines on atmospheric mixing should be far less, as the air is already turbulent and well-mixed in these regions.

 

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Finding the right mix indeed is the biggest technological challenge, together with means for storage and distribution. A grid for power distribution for renewables has to be much more flexible due to the inpredictability.

Edit: ... that leads us to home made electricity, if local conditions permit. Quite a few here (San Miguel de La Palma) have disconnected themselves from the public grid.

 

Edited by Green Baron

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36 minutes ago, peadar1987 said:

Well the actual source said "from 0 to 5%". Implying 5% is the absolute upper limit, and most places would get far less. Solar is not without its impacts as well, I think the best form of renewables will depend very strongly on the exact area. The researchers have noted that in mountainous or wooded areas the impact of wind turbines on atmospheric mixing should be far less, as the air is already turbulent and well-mixed in these regions.

With the tiny farms we see---the one I can see from my house has maybe 25-50?---it's not a huge thing, but those farms also produce meaningless amounts of power (the power density of wind is ~2.1W/m2). I seem to recall seeing something that said to just cope with annual growth in electrical need the world would need to cover an area the size of a middle of the road US state entirely with wind turbines... each year, every year. Wind power is silly, frankly. It's also incredibly ugly, and visible for vast distances, so the ugliness matters. Having something ugly that you have to be parked next to to see is no big deal, spreading the ugliness over 10s of thousands of square kilometers is criminal, IMO. I don't like billboards, either, BTW :wink: .

Edited by tater

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Well, i agree with the uglyness and noise and some sites could have been chosen more wisely (though i wouldn't call it criminal), but the power output is not that bad and i wouldn't say it is silly. A decent turbine produces 2-6MW if the wind blows (needs less than one might assume), some of the offshore parks produce power in the range 0.5GW and slightly more. That's not as much as a nuclear or fossil powered power plant can do but wind energy can contribute its part.

We just don't want it right in front of out door. The "ugliness" of a nuclear or a correctly cleaned coal power plant is just less visible to the human eye ...

btw: in front of the door of those on the other side of the island, above Santa Cruz, is a heavy oil power plant with a constant smelly blue cloud over it. I wouldn't want to live there, people often complain about the bad air. But the power company is state owned and of course everything is in compliance with the rules ...

Edited by Green Baron

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3 hours ago, tater said:

Unless someone has data on how a persistent reduction in wind in a given ecosystem affects the life there, you basically cannot say one way or another what the effect might be. For people who want policies based on "just in case..." this seems pretty odd.

I suppose you could look at prevailing wind directions, and see if there are any critters or plants that prefer the open vs lee sides of rocks.

Reduced wind speed would have close to no impact. Yes it might change a bit so other plants do better downrange, but this is the same effect as hills or even tall trees gives. 
Only negative ecological effect wind energy have is blade strikes on large birds. 

And yes its funny how some environmentalists start to go after wind power once it make economical sense. 
No it can not solve your energy needs but works well if combined with an fast ramped source like hydro or gas it works very well. 
 

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