MIT analysis suggests generating electricity from large-scale wind farms could influence climate...

[OKIsItJustMe]

http://web.mit.edu/newsoffice/2010/climate-wind-0312.html

Wind resistance

MIT analysis suggests generating electricity from large-scale wind farms could influence climate — and not necessarily in the desired way.

Morgan Bettex, MIT News Office

March 12, 2010

Wind power has emerged as a viable renewable energy source in recent years — one that proponents say could lessen the threat of global warming. Although the American Wind Energy Association estimates that only about 2 percent of U.S. electricity is currently generated from wind turbines, the U.S. Department of Energy has said that wind power could account for a fifth of the nation’s electricity supply by 2030.

But a new MIT analysis may serve to temper enthusiasm about wind power, at least at very large scales. Ron Prinn, TEPCO Professor of Atmospheric Science, and principal research scientist Chien Wang of the Department of Earth, Atmospheric and Planetary Sciences, used a climate model to analyze the effects of millions of wind turbines that would need to be installed across vast stretches of land and ocean to generate wind power on a global scale. Such a massive deployment could indeed impact the climate, they found, though not necessarily with the desired outcome.

In a http://www.atmos-chem-phys.net/10/2053/2010/acp-10-2053-2010.html">paper published online Feb. 22 in Atmospheric Chemistry and Physics, Wang and Prinn suggest that using wind turbines to meet 10 percent of global energy demand in 2100 could cause temperatures to rise by one degree Celsius in the regions on land where the wind farms are installed, including a smaller increase in areas beyond those regions. Their analysis indicates the opposite result for wind turbines installed in water: a drop in temperatures by one degree Celsius over those regions. The researchers also suggest that the intermittency of wind power could require significant and costly backup options, such as natural gas-fired power plants.

Prinn cautioned against interpreting the study as an argument against wind power, urging that it be used to guide future research that explores the downsides of large-scale wind power before significant resources are invested to build vast wind farms. “We’re not pessimistic about wind,” he said. “We haven’t absolutely proven this effect, and we’d rather see that people do further research.”

...

[Ian David]

1. The good news is, windfarms on water will LOWER temperatures.

Prinn cautioned against interpreting the study as an argument against wind power, urging that it be used to guide future research that explores the downsides of large-scale wind power before significant resources are invested to build vast wind farms. “We’re not pessimistic about wind,” he said. “We haven’t absolutely proven this effect, and we’d rather see that people do further research.”

[OKIsItJustMe]

4. In short, very large wind farms have the potential to affect climates

They may warm on land, they may cool on the water.

More research is appropriate.

[kristopher]

7. This is the second study reporting similar *microclimatic* results.

It doesn't affect climate, just the specific areas where the wind farms operate - maybe.

A good thought experiment is this. Equate one wind turbine to 6 large tress in terms of the effect on the transfer of energy in wind. Would you object to planting millions of trees on the basis of the idea that they will disturb the flow of energy in the wind?

[OKIsItJustMe]

9. From the article:

...

For the land analysis, they simulated the effects of wind farms by using data about how objects similar to turbines, such as undulating hills and clumps of trees, affect surface “roughness,” or friction that can disturb wind flow. After adding this data to the model, the researchers observed that the surface air temperature over the wind farm regions increased by about one degree Celsius, which averages out to an increase of .15 degrees Celsius over the entire global surface.

...

[kristopher]

18. That doesn't makes sense.

I wrote, "A good thought experiment is this. Equate one wind turbine to 6 large tress in terms of the effect on the transfer of energy in wind. Would you object to planting millions of trees on the basis of the idea that they will disturb the flow of energy in the wind?"


Your reply, "For the land analysis, they simulated the effects of wind farms by using data about how objects similar to turbines, such as undulating hills and clumps of trees, affect surface “roughness,” or friction that can disturb wind flow. After adding this data to the model, the researchers observed that the surface air temperature over the wind farm regions increased by about one degree Celsius, which averages out to an increase of .15 degrees Celsius over the entire global surface."

Wind turbines affect the transfer of energy, they do not generate heat nor do they cause the planet to retain heat. While microclimatic effects could be expected, the idea that this would equate to an increase in global temperatures seems much more likely to be an artifact of the modeling than anything else.

[joshcryer]

28. Haha, bashing models.

Comparing wind turbines to trees. :rofl:

Fucking gold.

[OKIsItJustMe]

29. Perhaps you should read the paper...

http://www.atmos-chem-phys.net/10/2053/2010/acp-10-2053-2010.html

...

Abstract. Meeting future world energy needs while addressing climate change requires large-scale deployment of low or zero greenhouse gas (GHG) emission technologies such as wind energy. The widespread availability of wind power has fueled substantial interest in this renewable energy source as one of the needed technologies. For very large-scale utilization of this resource, there are however potential environmental impacts, and also problems arising from its inherent intermittency, in addition to the present need to lower unit costs. To explore some of these issues, we use a three-dimensional climate model to simulate the potential climate effects associated with installation of wind-powered generators over vast areas of land or coastal ocean. Using wind turbines to meet 10% or more of global energy demand in 2100, could cause surface warming exceeding 1 ◦ C over land installations. In contrast, surface cooling exceeding 1 ◦ C is computed over ocean installations, but the validity of simulating the impacts of wind turbines by simply increasing the ocean surface drag needs further study. Significant warming or cooling remote from both the land and ocean installations, and alterations of the global distributions of rainfall and clouds also occur. These results are influenced by the competing effects of increases in roughness and decreases in wind speed on near-surface turbulent heat fluxes, the differing nature of land and ocean surface friction, and the dimensions of the installations parallel and perpendicular to the prevailing winds. These results are also dependent on the accuracy of the model used, and the realism of the methods applied to simulate wind turbines. Additional theory and new field observations will be required for their ultimate validation. Intermittency of wind power on daily, monthly and longer time scales as computed in these simulations and inferred from meteorological observations, poses a demand for one or more options to ensure reliability, including backup generation capacity, very long distance power transmission lines, and onsite energy storage, each with specific economic and/or technological challenges.

...

The computed air temperature over the installation regions in Run L is elevated by more than 1 ◦ C in the lowest model layer (∼30 m thick at sea level) in many regions (Fig. 2), but the increase, averaged over the entire global land surface, is only about 0.15 ◦ C. Although the surface air temperature change is dominated by the increase over the wind turbine-installed areas (Fig. 1), the changes go well beyond these areas (Fig. 2). The frequency distributions for temperature also shown in Fig. 2. The global land-average temperature changes are 0.05, 0.16, and 0.73 ◦ C, respectively, for these three other land-based runs (VL, H and VH). In all these runs, except for Run VL, the global patterns of these changes are consistent with Run L (Fig. 2). These patterns also have some similarities to the previous study by Keith et al. (2004) over land, but not over the oceans, since that study assumed fixed ocean temperatures.

The warming caused by the wind turbines is limited to the lowermost atmospheric layers (Fig. 3). Above the planetary boundary layer, a compensating cooling effect is expected and observed in many regions, because the turbulent transfer of heat from the surface to these higher layers is reduced. This should be contrasted to the relatively uniformly distributed warming throughout the troposphere induced by rising greenhouse gases (IPCC, 2007).

...

[joshcryer]

31. They use the Community Climate Model (ie, a GCM).

They admit that over the oceans that their model is inadequate. But it is a very very robust analysis. This is leading edge stuff here. Bashing the model is just an insult to the science.

[bananas]

38. From the pdf

The report and a discussion paper can be downloaded free from http://www.atmos-chem-phys.net/10/2053/2010/acp-10-2053-2010.html

Their conclusion that if we got 10% of energy from offshore wind would cool the earth about 1C raises the possibility of completely addressing global warming by getting 50% or more energy from offshore wind.

The other question with this study is that they seem to be mixing electrical power and thermal power units incorrectly. They are modeling 44TWt power in 2100 with 4.4TWe power from wind. The 14TWt and 44TWt for 2002 and 2100 are based on primary energy consumption from fossil fuels, where 2/3 is waste heat. The 4.4TWe would be equivalent to 3 times as much thermal power, 13.2TWt, equal to current global thermal generation and fully 1/3 of expected power generation in 2100. So they seem to be modeling 1/3 of power from wind in 2100, not 1/10. They seem to be over-estimating the effect by a factor of 3.

1 Introduction

World energy demand is predicted to increase from
430 EJ/year (14 TW) in 2002 to 1400 EJ/year (44 TW)
in 2100 (Reilly and Paltsev, 2007). Any effective energy
contributor needs to be implemented on a very large scale
(e.g. provide 10% of the year 2100 demand). Among the
current energy technologies with low or zero greenhouse
gas (GHG) emissions, electrical generation using wind turbines
is percentage-wise the fastest growing energy resource
worldwide. In the US, it has grown from 1.8GW of capacity
in 1996 to more than 11.6 GW (0.37 EJ/year) in 2006, but
this is still negligible compared to future energy demand.

The solar energy absorbed by the Earth is converted into
latent heat (by evaporation), gravitational potential energy
(by atmospheric expansion), internal energy (by atmospheric
and oceanic warming, condensation), or kinetic energy (e.g
by convective and baroclinic instabilities) (Lorenz, 1967).
Averaged globally, internal energy, gravitational potential energy,
latent heat, and kinetic energy comprise about 70.4,
27.05, 2.5, and 0.05% respectively of the total atmospheric
energy (Peixoto and Oort, 1992). However, only a small fraction
of the already scarce kinetic energy is contained in the
near surface winds that then produce small-scale turbulent
motions due to surface friction. Eventually the turbulent motions
downscale to molecular motions, thus converting bulk
air kinetic energy to internal energy.

However, it is not the size of these energy reservoirs, but
the rate of conversion from one to another, that is more relevant
here. The global average rate of conversion of largescale
wind kinetic energy to internal energy near the surface
is about 1.68W/m2 (860TW globally) in our model calculations.
This is only about 0.7% of the average net incoming
solar energy of 238 W/m2 (122PW globally) (Lorenz, 1967;
Peixoto and Oort, 1992). The magnitude of this rate when
wind turbines are present is expected to differ from this, but
not by large factors. The widespread availability of wind
power has fueled substantial interest in harnessing it for energy
production (e.g. Carter, 1926; Hewson, 1975; Archer
and Jacobson, 2003). Wind turbines convert wind power into
electrical power. However, the turbulence near the surface,
which also feeds on wind power, is critical for driving the
heat and moisture exchanges between the surface and the
atmosphere that play an important role in determining surface
temperature, atmospheric circulation and the hydrological
cycle.

Because of the low output (MW) of individual wind turbines,
one needs to install a large number of the devices to
generate a substantial amount of energy. For example, presuming
these turbines are effectively generating at full capacity
only 1/3 of the time, about 13 million of them are needed
to meet an energy output of 140 EJ/year (4.4 TW), and they
would occupy a continental-scale area. While the amount
of energy gained from global deployment of surface wind
power may be small relative to the 860TW available globally,
the accompanying climate effects may not be negligible.
A previous study using atmospheric general circulation
models with fixed sea surface temperatures suggests that the
climatic perturbation caused by a large-scale land installation
of wind turbines can spread well beyond the installation
regions (Keith et al., 2004).

[joshcryer]

39. Wrong on both counts.

The paper does not say that it would "cool the Earth 1C." The ocean model, where the cooling occurs, is in fact stated by the authors to be inadequate.



The authors come short of stating that it would result in a total warming, because the total picture is unclear. More modeling of the oceanic effect will need to be explored.

Using wind turbines to meet 10% or more of global energy demand in 2100 could cause surface warming exceeding 1C over land installations. Significant warming and cooling remote from the installations, and alterations of the global distributions of rainfall and clouds also occur.

As far as the wind calculation, it's not off by as much as you claim (though I agree they did miss the efficiency boost from going with renewables). Jacobson claims we need 40-85 TW of wind by 2030 to be energy self-sufficient. The 4.4 TW in the paper by 2100, then, is reasonable. What is missing in the calculation is that, really, they are going with a wind-only scenario and not considering other baseload providers. I would like to see what Jacobson's 3.8 million wind turbines would do to the environment. Certainly if you extrapolate Jacobson's numbers to 2100 the 13 million turbines envisioned by the paper could be reasonable, though perhaps by accident.

The point still remains that very large wind programs will affect the environment globally.

[kristopher]

42. That is no different than saying 20 million trees are going to affect the environment globally.

[joshcryer]

43. Nonsense.

Trees aren't as tall and have different characteristics, they had to hard code the wind turbine characteristics.

[kristopher]

44. It isn't nonsense at all.

The issue is aggregate drag. In the ocean you are working with millimeter height waves to calculate drag, on land it is more complex due to the varied terrain, however it is all the same basic forces at work.

Although the number is very generalized, going from 10 meters to 80 meters would be about 20% difference in the wind velocity with no appreciable difference in the mass. Factor in the difference in area obstructed (and the tree is going to block more wind per meter^2 than the turbine) and 20 million trees for 4 million turbines is being more than fair.

[OKIsItJustMe]

47. Thought-provoking picture

http://www.guardian.co.uk/environment/gallery/2010/mar/11/beauty-of-wind-power

Clouds form in the wake of Denmark's Horns Rev windfarm – one of the world's largest at sea

[joshcryer]

30. Trees are evolved to disburse energy, not absorb it.

A tree will sway in the wind no matter which way the wind is blowing because its limbs create circulatory effects. Trees also aren't typically 80 meters or taller.

[kristopher]

33. That was why I said 6 tree/turbine.

And when the branches flex they absorb kinetic energy from the wind.
It is a reasonably accurate visualization aide to help conceptualize the scope of the issue being studied.

"Above the planetary boundary layer, a compensating cooling effect is expected and observed in many regions, because the turbulent transfer of heat from the surface to these higher layers is reduced."

While study is warranted, it is unlikely to result in anything of consequence, IMO.

[joshcryer]

37. I trust the Community Climate Model and their analysis over your statements.

You haven't done a thorough analysis of what they've done here. The CCM3 is very robust, their over-land analysis is probably very accurate. They need to do more modeling to determine the true effects of wind over water, since the CCM3 lacks in that area. But it can be done and should be. The code is open source, you can put in their parameters if you want. I'm sure some wind interest groups will play with their method in the coming future.

I said at the bottom of this post that it could be a good thing.

A denialist would say CCM3 doesn't "result in anything of consequence." But they'd just be referring to its projections for temperature and weather variation due to GHGs.

[thereismore]

2. Burning coal would raise temps a lot more, so would nuclear. Hot components. nt

[Statistical]

5. LOL. Science is dead in the United States.

Look up how much heat the sun transfers to the earth each day.

Then compare that to all nuclear reactors in the world about 400MW e. Assume 33% efficiency so that is 1200MW t.





















In case you don't want to do the math.
All forms of all power (including fossil fuels, transportation, heating, etc) used by mankind is 487EJ annually. In one year the sun transfers 3,850,000. The heat output of mankind is 0.0126%. If heat output of mankind increased by a factor of 8000x it would equal 1% of energy sun transfer to earth.

The earth is getting warmer not because of any heat output mankind could ever possibly hope to achieve but rather a small increase in GHG means a tiny % more of the 3,850,000 EJ of energy.

[kristopher]

10. That isn't the comparison that was made.

It isn't solar insolation vs thermal generation, it is thermal generation vs renewable energy extraction.

Thanks for demonstrating the reality of your headline "Science is dead in the United States."

[Statistical]

15. All thermal output of mankind is a rounding error on total heat system called the earth.

Ending fossil fuel use because of therm output is not based on science.
We could increase amount of heat generated on the planet by a factor of thousands and not increase temperature of the planet by any meaningful way.

However GHG emitted by fossil fuels increase the amount of heat trapped by a tiny tiny tiny percentage. However the sun outputs so much power even a tiny % is enough to affect the climate.

Mankind's heat output has no relevance in a discussion of climate change or the environment. Ending GHG is the only concern.

[joshcryer]

17. Be very careful here.

The poster you are talking to is obsessed with heat output of humans:

http://upload.democraticunderground.com/discuss/duboard.php?az=show_mesg&forum=115&topic_id=207825&mesg_id=207825

http://www.democraticunderground.com/discuss/duboard.php?az=show_mesg&forum=115&topic_id=208318&mesg_id=208318

It is a denialist position and it illustrates well where the poster actually stands as far as GHGs are concerned.

[kristopher]

19. That discussion was about your ignorance of the peer review process.

Anything else is another product of your fevered imagination.

[joshcryer]

21. That discussion was with regards to your denial of CO2 forcings.

As you even attempted to downplay it before in the past: http://www.democraticunderground.com/discuss/duboard.php?az=view_all&address=115x208065

These findings mean that we can now say: if you emit that tonne of carbon dioxide, it will lead to 0.0000000000015 degrees of global temperature change. If we want to restrict global warming to no more than 2 degrees, we must restrict total carbon emissions – from now until forever – to little more than half a trillion tonnes of carbon, or about as much again as we have emitted since the beginning of the industrial revolution.

(Your emphasis.)

[kristopher]

26. Did your mother drop you on your head when you were a baby?

You have such limited reasoning ability it is hard to explain otherwise. Your conclusions do no follow from the evidence you offer.

[joshcryer]

32. *shrug* you're the one continuing the waste heat mantra.

[thereismore]

22. Exactly. The issue is how much heat is generated on top of solar input. If wind power

is a problem, then I guess we should all commit suicide because thermal power is so much worse. Some people are just so ignorant it hurts.

[Statistical]

23. That wasn't the conclusion of the MIT study.

The heat of the turbines was negligible and for all intents and purposes can be considered 0.

The heat of a turbine, or nuclear plant, or even coal plant increases the temperature of the planet by such a negligible (not even recordable) amount that it isn't worth considering.

Read it again, maybe you will understand.

[thereismore]

35. OK I will. Thanks. nt

[NNadir]

11. Well, um, speaking of assumptions, you're asking an some here.

You are assuming that the claimant can do calculations involving energy.

That is not a good bet.

Consider all the people who claim that a solar PV plant is comparable to a gas (or nuclear) plant based on peak "watt" figures.

There are very few folks of this type who are even remotely familiar with that troublesome stuff called "numbers."

Hey I'm enjoying your posts quite a bit.

Did you used to post a lot over at Kos in the old days under another name? You remind me of someone over there I liked a great deal, with a good solid knowledge of probability theory and a dry and sarcastic wit of a type of which I am, um, quite fond.

Your screen name here makes me think of him or her.

Never met him or her personally, never talked with him or her but he or she taught me quite a bit when she or she showed up in my diaries.

[thereismore]

24. So I guess you also believe that running my car is soooo insignificant compared to sun

input to Earth that something like global warming cannot exist. Right? Don't answer, because I know you are a proud fool.

[Statistical]

27. The heat from your car IS insignificant. The GHG from your car is very significant.

The amount of heat your car can produce in a billion years is negligible.

However enough GHG can cause the heat from sun which is trapped to increase by a tiny tiny tiny percent. GHG don't increase the amount of the sun's heat which is trapped by very much. They increase it by a tiny fraction of one percent. However the suns output is so massive (a couple magnitudes more than all heat ever generated by all humans since the beginning of time) that the tiny increase results in a very real amount in nominal terms.

Thus the heat from your car is negligible. The additional heat from the sun that the GHG from your car can trap is NOT negligible.

[joshcryer]

34. The heat from albedo modified pavement cars drive on is more significant than the cars.

We're talking about tens of thousands of years for humanities waste heat to matter, it could be completely negated simply by doing millennial aerosol sprays, or just waiting for a volcano to erupt.

The person who believes the waste heat thing has been reading too much dishonest anti-science propaganda.

[thereismore]

36. Right. Thank you, I misread something. nt

[Statistical]

40. No problem. Actually I am glad you brought it up because it is a common misconception.

If we cut human heat output by 90% but don't reduce GHG the sun will still kill the planet.
On the other hand if we increase heat output by 5000% and cut GHG by 90% we have the chance to stop runaway global warming.

The sun is so powerful than even a tiny change in the retained heat will destroy our climate.

[midnight]

6. Exactly, so why do we continue to use these sources?

[Statistical]

8. See above. The earth isn't getting warmer because of manmade heat sources.

[kristopher]

12. Yes it is.

There is research that shows both rapid warming and research that shows much more gradual warming from thermal generation of power. The question isn't whether or not, but how rapidly and how significant the level.

[joshcryer]

16. Nordell

:rofl:

[OKIsItJustMe]

13. Well... let's say that manmade heat sources are a relatively minor cause of warming

The primary cause appears to be greenhouse gases and aerosols.

[Vincardog]

3. SO one MODEL shows this result. What result does this model show for burning more coal?

Science marches on.

[OKIsItJustMe]

20. False dichotomy

The researchers specifically say “We’re not pessimistic about wind,” ... “We haven’t absolutely proven this effect, and we’d rather see that people do further research.”

Pointing out that large wind farms may have unintended effects does not mean they're advocating burning coal instead.

[Vincardog]

45. I only asked the question "What does this model show for that scenario?" That is what you do with

models.

[OKIsItJustMe]

46. That's what you do with models, if that's what the models are designed to do.

In this case;

http://www.atmos-chem-phys.net/10/2053/2010/acp-10-2053-2010.html

... To explore some of these issues, we use a three-dimensional climate model to simulate the potential climate effects associated with installation of wind-powered generators over vast areas of land or coastal ocean. ...

[joshcryer]

25. Global warming can reduce wind speeds, so this artificial variance can be good.

Check this out: http://articles.sfgate.com/2009-06-11/news/17207770_1_wind-power-global-warming-study

More studies need to be done to bring these two concepts together.

[joshcryer]

14. This could be a good thing, since it creates an artificial temperature variance.

[NNadir]

41. Oh good. Let's do an experiment!!!! For added fun, why don't we experiment with different gas

mixtures in the atmosphere!!!!

Maybe if we add some carbon dioxide, we can increase the strength of the wind I bet.

I hear they have some bitching winds on Venus.

[Kolesar]

48. Like huffing airplane glue?

before you post??