German Professor: Wake Effect Decreases Wind Farm Efficiency, Contributes to Warming

From the NoTricksZone

By P Gosselin 

First mocked, then victorious: The turbine slipstream dispute

By KlimaNachrichten
(Translated by P. Gosselin)

Professor Gerd Ganteför was called a lot of names when he reported on the so-called wake effect of wind turbines on the high seas in spring 2024. Wind turbines in wind farms not only take the wind away from each other, they can also have an impact on the wind behind the turbines up to 100 kilometers away.

In the meantime, the realization has also reached the windpark operators. The company Orstedt, which is heavily involved in so-called renewable energies, has some interesting results on its website. In a nutshell, it says that the turbines in the network deliver less yield, which means that the profitability per turbine decreases.

Overall, electricity production increases with more wind farms, but also the time until the investment per turbine pays off. The yield decreases if the calculated 4,000 – 4,500 hours of electricity generation per year are not achieved. The effect is likely to increase with more and more wind farms. It’s like a downward spiral. Let’s see what the German response to this is. It wouldn’t be surprising if it was to pay even more feed-in tariffs.

The size of the German areas is not the decisive factor. ‘Theoretically, much higher capacities than 70 gigawatts could be built there,’ says Martin Dörenkämper from Fraunhofer IWES in Oldenburg.

Admittedly, the wake effects would increase if the wind turbines were planned even closer together than they already are. But overall electricity production would still increase, even if the yield per turbine were lower. The question is therefore not whether Germany has enough space for 70 gigawatts, but how many terawatt hours of electricity can be produced each year – and at what price.

The higher the power density and the lower the yield per turbine, the more difficult it will be for the operator to refinance the construction and generate a return on investment.”

In his video, Ganteför explains that it is now possible to visualize the wake effect with the help of radar images from the Sentinel 2 satellite. In spring, he was ridiculed for this theory.

He points out that the wake effect can have various effects. On the one hand, there are the turbines on land, which could receive less wind, and the possible warming behind the turbines. Also there’s the influence of precipitation. Ganteför calls for more research in this area.

Two years ago, the Fraunhofer Institute Hereon already pointed out another problem. Another effect: disturbing the stratification of the water can have an impact on plankton production, i.e. the start of the food chain.

Another consequence of wake vortices is the reduction of shear-related processes on the sea surface. In other words, the turbulent mixing of the water surface caused by the winds is reduced for dozens of kilometers around the wind farm.

Water is usually stratified, e.g. a layer of warmer water lies on top of a layer of cold water.

The natural stratification is disturbed by the wind farms. Due to the reduced mixing, a more stable stratification of the water is favored. This was particularly noticeable during the decline in summer stratification. The natural stratification of the water is particularly striking in summer and decreases towards the fall. In the area of the wind farms, however, a more stable stratification was calculated outside of the seasonal fluctuation.

What do the results mean for the North Sea?

‘The magnitude of the induced mean changes does not indicate serious local effects, but far-reaching structural changes are occurring in the system,’ says Christiansen. ‘The changes in currents and mixing are likely to affect plankton production and food web structure and may influence the functioning of protected areas. It is therefore important to take these consequences into account when developing marine protection concepts,’ says Prof. Corinna Schrum, and Hereon Institute Director. Schrum provides an outlook for the implementation of the results, adding that further studies are required to analyze possible feedbacks on the air-sea exchange. A change in this exchange has a potential impact on regional atmospheric conditions and ecosystem dynamics and will be the subject of further studies.”

That doesn’t sound like settled science at all.

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September 20, 2024 2:28 am

Is it all just hot air then?

I’ll get my coat……..

strativarius
Reply to  HotScot
September 20, 2024 2:58 am

Given that survival time in the North sea is no more than about an hour it could do with warming up.

Michael S. Kelly
September 20, 2024 2:43 am

I don’t know why this hasn’t been an area of research from the beginning of large scale wind farms. We are essentially interfering with the major transport mechanism of the biosphere and troposphere, without a thought of the effects – or even a thought that there may be any effects. I fear that there may be many more effects than we can even suspect currently, given our scattered knowledge base on the influence of microbial diaspora and wind-borne transport of vital minerals. This is screwing with the environment on a huge scale, without any consideration of consequences.

Reply to  Michael S. Kelly
September 20, 2024 2:56 am

All becomes clear if you relocate your understanding of man made climate change from a scientific theory to political propaganda.

Greens don’t care about the environment, they are now pressure groups for renewable energy firms, and useful idiots for those seeking to establish an international totalitarian government using the UN

Scissor
Reply to  Leo Smith
September 20, 2024 4:47 am

That about sums it up.

Sparta Nova 4
Reply to  Leo Smith
September 20, 2024 7:40 am

You omitted the rich oligarchs stuffing their pockets with the money robbed from the deplorables.

another ian
Reply to  Leo Smith
September 20, 2024 3:33 pm

This goes with that IMO

“The Green Industrial Complex: The CEO of WWF is paid up to a million dollars to save “nature” ”

https://joannenova.com.au/2024/09/the-green-industrial-complex-the-ceo-of-wwf-is-paid-up-to-a-million-dollars-to-save-nature/

Reply to  Michael S. Kelly
September 20, 2024 3:10 am

You mean it isn’t “free” energy?

I wonder how many politicians and policy makers could recite the first law of thermodynamics.

strativarius
Reply to  David Pentland
September 20, 2024 3:51 am

Free: “”Paid for by others…””

“”Keir Starmer has come under scrutiny over the past week for the more than £100,000-worth of gifts he has accepted.  

It started with controversy over his wife’s clothes and has escalated since Sky News’ Westminster Accounts project revealed he has been gifted more freebies and hospitality than any other MP since 2019 “
https://news.sky.com/story/keir-starmers-freebies-everything-you-need-to-know-and-why-theyre-proving-so-controversial-13217722

Rich
Reply to  Michael S. Kelly
September 20, 2024 5:38 am

Thank you. In my opinion, we are already extracting enormous amounts of energy from the earth’s climate (sorry if that’s not the correct word) without any apparent regard to how it’s going to affect the climate or environment. There’s definitely going to be an impact….

Sparta Nova 4
Reply to  Rich
September 20, 2024 7:41 am

Perhaps energy system instead of climate. Still searching for the optimum phraseology.

Reply to  Sparta Nova 4
September 20, 2024 6:42 pm

Something like: “we are removing the energy from the air that drives weather systems. There will be a price to pay.”

CD in Wisconsin
Reply to  Rich
September 20, 2024 9:32 am

Still searching for the optimum phraseology.

Might I suggest natural systems? And this is something I have always wondered about as well.

What are we doing to the Earth’s natural systems when we extract wind energy from them, especially if we plan on doing it (on land and sea) on a large scale? What are we doing to the Earth’s natural systems if and when we intercept solar energy on a large scale to generate electricity?

Inquiring minds want to know.

Sparta Nova 4
Reply to  CD in Wisconsin
September 20, 2024 11:48 am

The basis of all of it is energy and the system constantly trying to achieve equilibrium given constantly changing inputs, such as a rotating planet.

While natural systems is a good phrase, I would prefer to see energy in the basic description.

Having studied radar, it is clear that when EM energy intercepts solids and liquids, it induces electric current. Before some yelps about insulators, one must appreciate the definition of insulator is greater than some ohmic value, usually 10M.

The point is, sunlight already is turned into electricity. It is the facilities that occupy square miles, often on concrete slabs that are the greater impact. Plus such structures create the equivalent of urban heat islands. Moisture does not get into the soil, plants do not grow, all of it.

All that said, yours is a very valid question for which no one has a comprehensive answer.

Wind generation is even more detrimental.

Reply to  Michael S. Kelly
September 20, 2024 5:48 am

The lead photograph is at least 10 years old.
The first wind turbine takes energy from the air, which causes condensation, etc., similar to contrails of a plane
The first wind turbine has the highest efficiency, because it has undisturbed air
The following wind turbines all have lesser efficiencies. Old news.
This has been measured by owners, but no published
The pictured wind turbines are much smaller than recent wind turbines, which have had torsional blade failures.
Stresses on 390 ft blades become enormous, as they sweep 800 ft circles through variable speed, sometimes gusty, wind fields.
Extrapolating existing designs for longer blades is no longer applicable.

Reply to  wilpost
September 20, 2024 6:26 am

‘The lead photograph is at least 10 years old.”

But what a rare and beautiful visualization of the inefficiencies, which are always there. Those plumes of turbulence continue to dissipate energy, which is no longer available to the leeward turbines.

Wind turbines are 20% to 40% efficient at converting wind into energy.”
https://www.epa.gov/sites/default/files/2019-08/documents/wind_turbines_fact_sheet_p100il8k.pdf

Reply to  wilpost
September 20, 2024 7:30 am

I wonder if changing the heights of the turbines, so that they vary, would mitigate the loss of efficiency?

This old engineer has always been a Mister-FixIt, so I can’t help think of ways to make them work better – even if they are ultimately doomed by the intermittentcy.

I’m surprised that wind turbines aren’t much taller, to take advantage of faster, more consistent winds further from the surface. My suspicious brain says the typical turbine design is a result of wanting the minimum cost design to milk the most amount of subsidies – especially the payments for curtailed production.

Iain Reid
Reply to  PCman999
September 20, 2024 7:59 am

PC Man,

much taller equals a stronger support, both of the structure and of the base due to the increased leverage. But taller won’t dimish the problem outlined in the article..

Reply to  wilpost
September 21, 2024 7:37 am

A more complete comment
.
Offshore Wind a Suicide Pact

https://www.windtaskforce.org/profiles/blogs/biden-30-000-mw-of-offshore-wind-systems-by-2030-a-total-fantasy
.
Massachusetts woke, leftist, deficit-spending, government, supported by lapdog, bought and paid for corporate Media, pushing for rushing dubious testing of pieces of 391-ft long blades, in a 300-ft facility, and using “extrapolation” of test results, to meet Biden/Harris environmentally disastrous, 13 MW, 850-ft-tall offshore wind turbine erection goals, is most irresponsible, because they produce electricity at 15 c/kWh, plus 2 c/kWh for grid re-enforcement and extension, plus 2 c/kWh for quick-reacting plants to counteracting the ups and downs of wind output, on a minute-by-minute basis, 24/7/365, including filling in during periods when there is almost no wind, which happen throughout the year, and could last 5 to 7 days. 
.
AN ABSOLUTELY FOOL-PROOF WAY FOR MASSACHUSETTS TO BECOME EVEN MORE UNATTRACTIVE TO INVESTMENTS FROM PRIVATE UNSUBSIDIZED, TAX-PAYING, JOB-CREATING BUSINESSES, as has happened in Germany and the UK
.
Their leftist governments making woke energy decisions are having adverse GDP repercussions throughout Europe.
.
Regarding grid-spacing of offshore turbines
.
The first wind turbine takes energy from the air, which causes condensation, etc., similar to contrails of a plane
The first wind turbine has the highest efficiency, because it has “less-disturbed” air
The following wind turbines all have lesser efficiencies. Old news.
This has been measured by owners, but no published
.
Stresses on 390-ft blades become enormous, as they sweep 800 ft circles through variable speed, sometimes gusty, wind fields.
The wind speeds vary from top to bottom and from side to side in each 800-ft circle
That creates huge VARYING, TORSIONAL forces on the blades as they rotate, in addition to all other forces.
This is in no way comparable to much shorter airplane wings.
Extrapolating existing designs for 391-ft blades is not applicable.
The torsional failures of 391-ft blades require complete redesign.

Sparta Nova 4
Reply to  Michael S. Kelly
September 20, 2024 7:39 am

I said from the beginning that wind turbines affect local environment. Even if just reducing air flow by converting air kinetic energy to turbine angular velocity. This is no surprise.

Ever see a motor boat? The wake even before the vessel starts moving.

Reply to  Sparta Nova 4
September 20, 2024 3:10 pm

The wake effect was never a problem until idiot greentards started the woke effect.

Frank Pouw
Reply to  Michael S. Kelly
September 20, 2024 11:31 pm

I think they,the agw community use the same technique as always. It’s inconvenient to tell the scientific truth because it not only intervenes the atmosphere air flow but much more important the money flow and we are talking about millions of euro/dollars. This guy is a danger for the agw community that’s why his was ridiculed because a lot of a lot of money costing jobs are at stake.
don’t talk to me about scientific integrity because there is only one world and that so called scientific world where fraudulent action is daily business because exactly the money must keep flowing not the wind.

joe-Dallas
Reply to  Michael S. Kelly
September 22, 2024 6:17 am

I am a competitive level cyclist –
Its well known that the cyclists sitting behind the lead cyclist uses less energy than the lead cyclist due to the draft. A cyclist sitting 4th or 5th wheel is often only expending 60%-70 of the wattage of the lead cyclists. Also true in the running sports, though less of a benefit than cycling. also true in auto racing.

So the article is definitely correct, though the wide spacing of windmills reduces the effect of the draft.

strativarius
September 20, 2024 2:53 am

“” turbines in the network deliver less yield, which means that the profitability per turbine decreases.””

I read in a [UK] report some time ago, I can’t remember where exactly, but it stated that turbines lose ~3% each year of operation; after ten years its lost almost a third. That too must have an effect on ‘profitability’, but as they get paid to switch off maybe that’s countered to a degree?

Certainly, the golden rule is whatever the negatives surrounding big wind might be, it’s a price worth paying for so-called clean energy.

Friday doublethink:

The science is settled… further studies are required…

Reply to  strativarius
September 20, 2024 3:21 am

I have read here that blades of the wind turbine last about 20 years. I have seen internet views of boneyards with enormous piles of used blades which can’t be recycled. I wonder have much a new set of blades would cost plus the cost of installation. Probably a lot.

strativarius
Reply to  Harold Pierce
September 20, 2024 3:38 am

“”whatever the negatives surrounding big wind might be””

In my judgement there are far more negatives, in fact there isn’t really a positive – unless you happen to have the bank account into which the subsidy money tumbles.

Editor
Reply to  Harold Pierce
September 20, 2024 3:52 am

Knock the whole lot over, and let them rot. While rotting, which could take a long time, they would be a haven for fish especially as trawlers wouldn’t be able to operate. Could be a massive benefit at low cost, maybe just $1bn per extra fish.

Reply to  Mike Jonas
September 20, 2024 5:50 am

They should be re-erected in posh neighborhoods which own them.

Sparta Nova 4
Reply to  Mike Jonas
September 20, 2024 7:45 am

Except the blades. Which is better? Fiberglass shards cutting tourists feed or those same shards in the bellies of fish being eaten?

Sparta Nova 4
Reply to  Sparta Nova 4
September 20, 2024 11:49 am
  • feet *
Reply to  Harold Pierce
September 20, 2024 5:51 am

And the cost of that wind machine not producing power until fixed.

Reply to  Harold Pierce
September 20, 2024 7:42 am

This one burned up near us a few years ago. I’m told that rather than repair, the operator tore it out, foundation and all

1000011091
Reply to  Harold Pierce
September 20, 2024 3:18 pm

Fiberglass and epoxy resins do not last 20 years outside absorbing UV rays and experiencing inclement weather.

Anyone that ever owned a boat that failed to store it properly can tell you that. It’s not rocket science.

Reply to  Harold Pierce
September 21, 2024 10:21 pm

Reported today.
Farmers in Australia have been warned to delay field work or wear safety helmets as pieces of blades are comming off wind turbines.
These turbines are new.

September 20, 2024 4:03 am

Wake Turbulence is well known,see https://www.faa.gov/air_traffic/publications/atpubs/aim_html/chap7_section_4.html

I guess one could say “settled science.”

strativarius
Reply to  George B
September 20, 2024 4:05 am

And then go on to say  “further studies are required…”

Jeff Alberts
Reply to  strativarius
September 20, 2024 5:09 am

Further predetermined studies are required.

September 20, 2024 4:51 am

I wonder if the downwind turbulence would also mean those wind turbine disintegrate faster. ??

Turbulence is great at wrecking things !

Editor
Reply to  bnice2000
September 20, 2024 5:59 am

Yes. Another problem is that as the rotors spin the blades see greater wind force at the top than at the bottom and may lead to fatigue damage. (I know very little about such issues in fiberglass and carbon fiber material, so take with a big grain of salt. Metal fatigue is a big issue, so that may impact other parts of turbines.)

An article about a study of turbulence and other effects is at https://web.archive.org/web/20111208232731/http://www.noaanews.noaa.gov/stories2011/20110426_windwakes.html . It includes a photo of a damaged bearing due to turbulence.

Reply to  Ric Werme
September 20, 2024 10:10 pm

You are quite right – operating a rotor (or wind turbine) in turbulent flow affects their fatigue life. Additionally, exposing the blade to an operating environment that varies once per revolution will affect blade life unless one uses a complex blade pitch control system.

(I spent more than a third of my career analyzing rotor blade dynamic loading. It is messy.)

Groggy Sailor
September 20, 2024 4:56 am

Further evidence there’s no such thing as “clean energy “.

Reply to  Groggy Sailor
September 20, 2024 5:52 am

Clean energy, wind, solar, batteries, etc., would not exist without huge subsidies
Therefore, it is screwed up energy, created by the government

Sparta Nova 4
Reply to  wilpost
September 20, 2024 7:47 am

Grid scale, true. There are examples of small installations that have done well.
It is not that solar and wind are evil. What is evil is political overrides of science and common sense.

Reply to  Sparta Nova 4
September 21, 2024 6:53 am

30 years of subsidies is evil, by definition

Robertvd
September 20, 2024 5:15 am

How to operate big fleets and the effect wind has. Just ask people like Horatio Nelson.

Reply to  Robertvd
September 20, 2024 5:59 am

The Spanish Armada misread the tide, current and wind, then ran into a storm north of Scotland, which destroyed almost all of it, and the Spanish empire started to come to its end, because almost all 100-y-old trees in Spain were gone and the Brits and Dutch made sure the Spanish could not get suitable wood elsewhere.

Dave Yaussy
Reply to  wilpost
September 20, 2024 6:15 am

I don’t think that’s correct. At that time Spain had colonized huge areas of the Americas that were full of suitable trees.

strativarius
Reply to  Dave Yaussy
September 20, 2024 6:56 am

And…. El Dorado

Reply to  Dave Yaussy
September 20, 2024 8:37 am

The Armada debacle was in 1588

Spain and the Dutch had an 80-y war, 1568 to 1648. The Dutch won.
The Peace of Utrecht codified the capitulation of Spain.

Spain could not get trees, etc., to Spain, because Dutch and UK battleships were intercepting/sinking Spanish ships on the Mediterranean and Atlantic Ocean .

Spain had borrowed much gold and silver from the Amsterdam Dutch Bankers, and did not pay back, so the Dutch fleet met Spanish silver ships and unloaded them at sea, and there was nothing Spain could do about it, because it had inferior “battleships” made with young/weak trees

The result was all sorts of tableware, etc., was made of silver in the UK, Netherlands, etc

Sparta Nova 4
Reply to  wilpost
September 20, 2024 7:47 am

That misread, as I recall, occurred during the retreat after defeat by the British fleet.

Sparta Nova 4
Reply to  wilpost
September 20, 2024 11:51 am

I will not use wiki as a source for anything.

Reply to  Sparta Nova 4
September 21, 2024 6:55 am

You have to be wise and selective

James Snook
September 20, 2024 5:39 am

Has anyone seen recent figures on output reduction due to turbine aging?

David Wojick
September 20, 2024 5:47 am

Good stuff but wake effects are not news. I wrote about them almost a year ago:
https://www.cfact.org/2023/12/01/nas-study-raises-concern-over-offshore-wind-harming-endangered-whales/

Editor
September 20, 2024 5:50 am

Oh good. I expected to be posting the Vattenfall image, but it’s right there at the top.

I consider it the most important photo ever taken of a wind project as it shows so clearly the downwind turbulence.

In farming country, wind turbine turbulence prevents the nightly temperature inversion from forming. This leads to warm wind that evaporates ground moisture instead of nighttime dew formation. Hence, greater reliance on irrigation and higher dew points well down wind, and hence warmer nighttime lows.

hdhoese
Reply to  Ric Werme
September 20, 2024 7:20 am

Interesting as some of these are on farmland with varying amounts of precipitation and other water supplies. Stratification also occurs in the ocean which can produce lowered oxygen and other effects. Almost everything tends to sink in the ocean. Also varies in amounts of nutrients blamed on not so “dead zones” which do enhance oxygen demand but can also increase productivity. The problem is that there are real human effects that need attention which may get overshadowed without trial experiments.

Reply to  Ric Werme
September 20, 2024 7:35 am

Soooo… Wind turbines cause climate change!

Sparta Nova 4
Reply to  Ric Werme
September 20, 2024 7:48 am

One more positive </sarc> benefit of wind turbines in farming country.

And truly a benefit </sarc> to the climate (i.e., weather.).

Scarecrow Repair
September 20, 2024 7:33 am

Sailing ships have long known about wake effects. It’s a standard tactic in modern-day races, and was a standard combat tactic during the days of sail warships. How anyone could actually believe it doesn’t affect wind turbines is beyond me. Well, not really, when it comes to propaganda.

Sparta Nova 4
Reply to  Scarecrow Repair
September 20, 2024 11:51 am

I forgot about that. You are correct. Been a few decades since last I sailed. Age does not have many benefits.

Reply to  Sparta Nova 4
September 20, 2024 10:14 pm

Consider the alternative

John XB
September 20, 2024 8:51 am

4 000 to 4 500 hours generation per year for the investment to pay off? That’s at most around half the year, and in a free (unsubsidised, un-rigged) market cannot be profitable.

No enterprise whose output is not continuous, is unpredictable, and only produces for between one-third and half the time, is viable.

The supposed ‘wind always blowing somewhere’ doesn’t help the profitability of the subsidy farms where the wind isn’t blowing. It is of no help to supermarket A who has had to close for a few hours, that supermarket B the other side of town has its doors open selling groceries.

Net Zero is a physics and economics free zone.

September 21, 2024 2:50 am

If a butterfly flapping its wings allegedly can cause a hurricane elsewhere, then potentially what effect can all of these windmills have on the weather?

joe-Dallas
September 22, 2024 6:22 am

I would like to see good studies on the productivity of the land surrounding the windmills

Marc Jacobson in his 100% renewable studies frequently claims the only loss is the acreage lost due to the actual footprint of the windmill tower and the road going to the tower. He claims the remaining land retains full use.

I find that claim by jacobson to be dubious. the change of wind patterns very likely has some effect on the land productivity, either from reduced crop production or ranching. If you drive by a wind farm, one thing that is obvious is the cattle tend to congregate upwind of the windmills, rarely downwind due to the noise.

joe-Dallas
Reply to  joe-Dallas
September 22, 2024 7:00 am

Just attempted a google search on the effect of windfarms on farming/agricultural/ranching productivity .

Either there is very little published research on the topic or the google wants to hide the data because the data is very negative.