Study: Wind power fiercer than expected

As US’ first offshore wind farm takes root, study indicates wind may be more powerful, turbulent than expected

This is an example of an offshore wind farm. CREDIT Kim Hansen, Creative Commons
This is an example of an offshore wind farm. CREDIT Kim Hansen, Creative Commons

University of Delaware researchers report in a new study that offshore wind may be more powerful, yet more turbulent than expected in the North Eastern United States.

The findings, published in a paper in theJournal of Geophysical Research: Atmospheres, could have important implications for the future development of offshore wind farms in the U.S., including the assessment of how much wind power can be produced, what type of turbines should be used, how many turbines should be installed and the spacing between each.

The study, led by Cristina Archer at UD and Brian Colle at Stony Brook University, analyzed historical data from 2003-2011 at the Cape Wind tower located near the center of Nantucket Sound off the coast of Martha’s Vineyard, Massachusetts, and collected complementary data at the same location in 2013-2014.

Co-authors on the paper, titled “On the predominance of unstable atmospheric conditions in the marine boundary layer offshore of the U.S. northeastern coast,” include UD professors Dana Veron and Fabrice Veron, and Matthew Sienkiewicz from Stony Brook.

The paper’s main finding is that atmospheric conditions around Cape Wind are predominantly turbulent, or unstable, which is in stark contrast to prevailing data from European offshore wind farms in the Baltic Sea and the North Sea. European studies of offshore wind document that atmospheric conditions there are predominantly neutral– meaning neither too windy nor too still, but somewhere in the middle, with unstable wind conditions occurring only 20 percent of the time.

“By contrast, our study found that wind conditions at Cape Wind are unstable between 40 and 80 percent of the time, depending on season and time of day,” explains Archer, an associate professor in the College of Earth, Ocean, and Environment’s School of Marine Science and Policy and Department of Geography and a governing member of the Center for Carbon-free Power Integration.

Stable, unstable and neutral

Explaining how wind can be stable, unstable or neutral is a tricky business, Archer says. When the atmosphere is stable, winds are smooth and consistent (think of when a pilot tells airline passengers to sit back and enjoy the ride because the weather is clear all the way to their destination).

When the atmosphere is unstable, it is similar to turbulence experienced by airline passengers during a flight — the wind is choppy and causes high winds from above and slow winds from below to crash into each other and mix together, causing a bumpy and unpredictable ride for the air current.

Neutral conditions hover in the middle, with an average amount of turbulence and wind speed variation.

“The advantage of these turbulent conditions is that, at the level of the turbines, these bumps bring high wind down from the upper atmosphere where it is typically windier. This means extra wind power, but that extra power comes at a cost: the cost of more stress on the turbine’s blades,” explains Archer.

An expert in designing offshore wind farms, Archer says the findings may have implication on how future offshore wind farms in the region are designed.

“If you have increased turbulence, you’re going to design a different farm, especially with regard to turbine selection and spacing. And guess what? Even the wind turbine manufacturing standards are based on the assumption of neutral stability,” Archer says.

Is something special going on in the North East?

No measurements exist of wind and turbulence around an offshore wind turbine’s rotor blades in the ocean in the U.S., because until now, none have existed. The first U.S. offshore wind farm is currently under construction at Block Island, off the coast of Rhode Island.

Instead, this type of data has been estimated based on either numerical simulations or using available buoy data to infer what the conditions would be at the height of the wind turbine’s rotor blades. But wind data measurements from 2003-2009 at the Cape Wind Tower, a multi-level tower with sensors positioned approximately 65 feet, 131 feet and 196 feet in height, have shown that the Cape Cod region’s atmospheric conditions are generally unstable. Neutral conditions only occur approximately 20 percent of the time.

In 2013 and 2014, with funding from the U.S. Department of Energy, the UD-led research team launched a campaign they coined IMPOWR, Improving the Modeling and Prediction of Offshore Wind Power Resources, to validate the Cape Wind tower findings with additional measurements.

The IMPOWR researchers flew a plane around Cape Wind 19 times over two summers, above and around the tower, and measured wind, temperature and humidity during various weather conditions. They also installed new wind and wave sensors on the Cape Wind platform.

Combined with buoy data from just above the water’s surface and with the historical data from Cape Wind, the IMPOWR field data painted a surprising and yet consistent picture of the area’s wind resources.

“We get the same message whether we look at the turbulence from the flights or from the sonic anemometers on the tower, or whether we consider the wind speed data alone. The marine atmosphere is more likely to be unstable than neutral. Having three separate pieces of evidence that support the same finding allows us to be confident that there is something special going on,” she says.

Wind direction also plays a role in whether the wind is smooth or turbulent. When the wind comes from the southwest, the data show that wind tends to be more stable and to increase in speed from the bottom to the top of the rotor blades. But when the wind comes from the north, northwest or offshore, it is more likely to be unstable and to have a relatively uniform speed across the turbine rotor, Archer says.

Further study is needed to understand whether this phenomenon is localized in the Cape Cod area, along the East Coast in general, or present throughout the U.S., since other offshore wind installations on the East Coast are planned for Maryland, New Jersey and Massachusetts.

“It’s important to ensure that science doesn’t underestimate the possible wind resources,” Archer says. “Now that we know what is happening in Cape Cod, we have more work to do to determine whether it exists anywhere else or whether it is unique to this region.”


3 1 vote
Article Rating
Newest Most Voted
Inline Feedbacks
View all comments
August 11, 2016 4:30 pm

It’s unclear to me why models didn’t predict these results?

Reply to  Bartleby
August 11, 2016 4:49 pm

In the beginning “Scientists” created the results, on the second day “Scientists” created the models on the basis of their imagination, on the third day ….

Ron Abate
Reply to  petermue
August 11, 2016 6:13 pm

Exactly, instead of science-based policy we now have policy-based science.

george e. smith
Reply to  petermue
August 11, 2016 6:26 pm

“””””….. Study: Wind power fiercer than expected …..”””””
If you don’t mind, we’d rather wait until somebody competent is available to advise us on our windmill fan project.
Why would we want to hire somebody who simply didn’t expect such circumstances to occur.
This is not a toy amusement park we are planning, and we would rather get somebody who already fully expects these kinds of problems to occur; specially if we let some incompetent boobs, spend our money injudiciously.

M Seward
Reply to  petermue
August 12, 2016 4:55 am

and, (cutting to the chase) … on the seventh day they rested on their laurels, took lunch with the minister and confirmed their travel and accomodation reservations for Paris & New York and checked their bank accounts to confirm their funding was through.

Reply to  petermue
August 12, 2016 2:40 pm

Is it worse than we – YOU – thought?
Auto – noting that this study appears to involve real data.
Magic! Real data!

george e. smith
Reply to  Bartleby
August 11, 2016 5:46 pm

Models don’t predict what happens to a system that does not work according to the equations used to construct the model.
Martha’s Vineyard lies in a well known Hurricane and Perfect Storm zone, so it does not behave like a well engineered Venturi Duct operating in a laminar flow regime.
If I leave my front gate open (I don’t leave my front gate open), the wind in my front yard is highly turbulent and it disturbs the flowers in the garden so I can’t take close up photos of them with interesting insects visiting them.
So my front yard with the gate open, is a bad place to put a wind farm for the collection of solar thermal energy.
So far my front gate has not caught fire in the wind, but one of these days, somebody other than me is going to catch hell for leaving the front gate open.
Reynolds numbers do not describe the thickness of Aluminium foil wrapping that is used for cooking.
Does anybody in this focus group watching the glassy seas in that wind farm photograph know what Reynolds Numbers are good for ??
PS I see this focus group is a family affair.

Javert Chip
Reply to  george e. smith
August 11, 2016 9:00 pm

I’m gonna guess a few readers more-or-less understand Reynolds Numbers.
I totally don’t get the family affair thing.
Had enough coffee already?

Leonard Weinstein
Reply to  george e. smith
August 12, 2016 11:48 am

Why such hostile comments? I know well what Reynolds number is and why it is useful (my ScD is in aerospace engineering). What is your point?

george e. smith
Reply to  george e. smith
August 12, 2016 1:50 pm

“””””….. Co-authors on the paper, titled “On the predominance of unstable atmospheric conditions in the marine boundary layer offshore of the U.S. northeastern coast,” include UD professors Dana Veron and Fabrice Veron, and Matthew Sienkiewicz from Stony Brook. …..”””””
So Javert;
If you read the above very carefully; you just might find some uncanny similarities.
And Leonard’s comment answers his own question.

Reply to  george e. smith
August 12, 2016 8:38 pm

George: exactly right in my opinion.
When I looked into alternative energy sources I did consider wind, who wouldn’t? My land is on a ridgetop and has copious amounts of wind, some have been clocked at 110 mph sustained for over four hours and blew out a set of six Anderson “hurricane” doors in 2007. I’ve since replaced them with out-swinging doors and very much hope the next time it happens it won’t be disastrous as it was in 2007.
As you already know, wind power depends on laminar flow, not just wind. On a ridge, we don’t have that, so I opted for a 60KwH solar array since I’m in the lower latitudes and, in my experience, that was a good choice; a resounding success and one I’m very happy with since I now sell power to the local grid and manage a profit.
Wind power seems very ephemeral to me, not something I would design a public utility around. Thanks very much for your supporting opinion, I don’t believe it’s at all misplaced.

george e. smith
Reply to  george e. smith
August 12, 2016 11:05 pm

August 12, 2016 at 8:38 pm
George: exactly right in my opinion. …..”””””
I’m fully supportive of people who can using PV solar to supplement their home electricity or business for that matter, so long as they don’t expect others to pay for it for them, and it is always good to hear from a happy user like yourself.
But as you discovered, these wind turbines are a different thing all together.
We learned right here on this thread, thanks to knowledgeable WUWTers, that turbine propellers can be individually feathered to reduce vibration fatigue failure; but that raises a different issue.
So these new larger units seem to rotate at about 20-30 RPM, and lets assume they have smart feathered propeller blades.
So 20-30 times each minute, each one of those three blades gets exercised back and forth over some angle of attack range.
Well what could go wrong; after all helicopter rotors rotate faster than that and they cave a complex feathering system that gets worked over to keep them in the air.
But when was the last time one of these helicopters ran for 30 years without service to that rotor system.
Wouldn’t surprise me to learn that high performance military choppers get major rotor service perhaps every 100 flying hours or less.
Maintaining a reliable turbine propeller feathering mechanism sounds like a major service head ache to me.
I’m far more critical of confarnations like Ivanpah and Tonopah, because I know quite a bit about efficient non imaging optics , particularly as used in collection of solar radiant energy, either for concentrator PV cells, or concentrator thermal systems, and I routinely attend the annual solar energy symposium sponsored by the University of California, Merced under Professor Roland Winston, who literally invented the whole science of non imaging optics; and the DOE and NREL are co-sponsors of that symposium.
Next one is in October at UC Davis.
I imagine that if one studied the Ivanpah mirror array, and computed the cost of adding any one of those mirrors to the array, and also the net contribution to the output electricity, and the cost per kWh change that resulted from adding that mirror, we would find that many of those mirrors increase the cost per kWh so they should be eliminated from that array. (Now you could re-assemble those unnecessary mirrors into a new array around another tower).
I doubt that any of the mirrors on the south side of the tower can pay their own way.
Roland would freak out, if I told him I thought Ivanpah was a wonderful achievement; but he already knows, that I know better than that. He has designed cost effective efficient systems both PV and thermal for smaller scale solar energy systems for small communities in low income regions. His play pen at UC Merced (actually he’s in Atwater on the old B52 air base) has a solar thermal heating system for one of their buildings.

Reply to  george e. smith
August 13, 2016 5:39 pm

george e. smith: “Wouldn’t surprise me to learn that high performance military choppers get major rotor service perhaps every 100 flying hours or less.”
You mean this sort of thing?

Ian W
Reply to  george e. smith
August 13, 2016 6:20 am

Bartleby on August 12, 2016 at 8:38 pm
You are not selling power to the national grid, you are selling high cost power to other electricity consumers some of whom cannot afford your rates. One person’ssubsidy is another person’s bill.

Reply to  Bartleby
August 11, 2016 6:33 pm

The cell size (a few hundred km) and time step (a couple of ticks per hour) of a modern climate model doesn’t resolve “stable” and “unstable” yet.
Measurement is still the best for phenomena that are smaller than a decent sized country.

Reply to  Seth
August 11, 2016 7:54 pm

You could have stopped that last sentence after four words.

Reply to  Seth
August 11, 2016 7:55 pm

Oops…five words.

Reply to  Bartleby
August 11, 2016 11:42 pm

You got it in one mate, models.

Reply to  Bartleby
August 12, 2016 5:13 am

Maybe they should have consulted with cod fishermen instead of a computer model.

Reply to  Bartleby
August 12, 2016 6:17 am

Because they never bothered to sample wind speeds beforehand?

August 11, 2016 4:40 pm

“… we have more work to do to determine whether it exists anywhere else or whether it is unique to this region.”
IOW, ‘give us more money’.

John M. Ware
Reply to  Latitude
August 12, 2016 1:26 am

You forgot the pile of manure that should be accumulating behind and below the horse, which obviously is going nowhere fast.

Reply to  John M. Ware
August 14, 2016 3:16 pm

And Gore walking behind, shovelling it up and selling it to gullible politicians and ignorant consumers!

Wim Röst
August 11, 2016 4:53 pm

1. Flight data must be able to give important information about regional differences in (in)stability of the air.
2. The nearby Warm Gulfstream and the cold waters from the north must create a lot of local rising and descending air spots and so instability. Have a look at the Gulf Stream pattern and at the corresponding temperature differences of the ocean:,40.75,2629/loc=-69.715,41.413

Reply to  Wim Röst
August 12, 2016 2:55 am

Earth nullschool is a brilliant visualization of the Earth.
But that is the majority of what Earth Nullschool is. Much of what is portrayed on Earth nullschool is modeled or historical averages.
The currents portrayed are pure models. Much of the winds are pure models.
The sea surface temperatures are historical averages.
From Earth nullschool:

a visualization of global weather conditions forecast by supercomputers updated every three hours

ocean surface current estimates updated every five days
ocean surface temperatures and anomaly from daily average (1981-2011) updated daily”

Pretty pictures.
Definitely educational.
Almost zero up to the minute real time value data.
Let us know when they start loading actual unadjusted real time data from satellites, buoys, surface stations.

Ian W
Reply to  Wim Röst
August 13, 2016 6:38 am

That is what I was thinking turbulence from convection. This would not occur over the far cooler Baltic with its evenly distributed temperatures. These can be compared. simply on null school. No need for the flights and towers just look at the cumulus clouds.

August 11, 2016 4:55 pm

Windmills kill millions of birds and bats annually. News Windmills should be banned and those in service should be torn down. There are much better ways to generate electricity than windmills. We should stop going down this “windmill” road now.
Does anyone ever protest locating windmills in their area? Never hear of much. Maybe most folks don’t know about the massive deaths inflicted by windmills. I think massive protests are in order.
Where are the environmetalists. Where’s PETA? How do you live with yourselves remaining silent on this subject?
Where’s a Green or an Alarmist defending this slaughter of birds? Feel free to defend this practice right here.
I’m betting there will be no effort to defend this practice because there is no defense. Most normal people would be aghast if they knew the truth about windmills.

george e. smith
Reply to  TA
August 11, 2016 5:51 pm

Who cares about the Birds and the Bees; excuse me, I meant the Bats ??
I’m more concerned with the sounds and the eye sores disturbing the serenity of the Kennedy Asylum; excuse me, that’s Kennedy Compound, on Martha’s Vineyard.
Those special people need to be able to conduct their drunken excesses; well pool parties, in some measure of tranquility.

Tom Harley
Reply to  george e. smith
August 11, 2016 11:42 pm

Bees too George, apparently the low frequency noise makes them move on.

Reply to  TA
August 11, 2016 5:55 pm

There were some large protests in Ontario Canada having to do with placement of mills close to housing , but even those protests have been white washed by the MSM up there. Birds? The environmentalists don’t give a hoot about PEOPLE!.

Reply to  TA
August 11, 2016 6:30 pm

The typical greeny response is usually that “fossils fuel pollution kills more birds blah blah blah…” and then they cite some BS study about it. These things kill a high percentage of raptors too.

Reply to  TA
August 11, 2016 7:16 pm

The alarmists come back with a preposterous yarn about cats killing so many birds, anything else is just a drop in the bucket.
We have had many long discussions here about how thoroughly wrong this justification is.
For one thing, the birds killed by wind turbines include large migratory and predatory birds, which breed slowly and typically exist in limited numbers to begin with.
If the number of turbines is ever built that would be needed to replace fossil fuels to any significant degree, it would cause an ecological catastrophe, and likely lead to the outright extinction of many species.

Reply to  Menicholas
August 11, 2016 11:45 pm

If only they could train the windmills to kill cats we might be on a winner.

Reply to  Menicholas
August 12, 2016 6:53 am

Mjw August 11, 2016 at 11:45 pm
“If only they could train the windmills to kill cats we might be on a winner.”
I’m pretty sure there’s a lifetime train of grants in there somewhere. Better getting busy writing it up, Mjw.

Tom O
Reply to  Menicholas
August 12, 2016 8:26 am

Mjw – It really depends on what your opinion is of cats, doesn’t it? If they should be trained to kill anything, it might be best to train them to kill warmister politicians and that might save the planet.

Sweet Old Bob
Reply to  Menicholas
August 12, 2016 8:39 am

Mjw…..when cats fly….:)

Reply to  Menicholas
August 12, 2016 9:10 am

Sweet Old Bob: Which they will if they get hit by one of those blades.

Reply to  TA
August 11, 2016 8:04 pm

Soil disturbance is an issue that’s being over-looked with the construction of wind turbines.
Soils containing human pathogens can be and are released during construction phases of wind turbines which can then be washed into watersheds which supply rural water wells.
Other human pathogens can be spread from disturbed soils and carried by the wind to cause infections.
Animal infections can also be spread the by the same means from pathogen infested soils.
Rural residents are the most vulnerable as wind turbines are installed in rural areas.
Installing thousands of wind turbines in rural areas is inviting trouble.

Reply to  Barbara
August 12, 2016 10:20 am

Oh no! The billionaire from Colorado is insisting that his wind plant (not a farm—no one plants seeds…) is GOOD for Wyoming, miles from where he lives, of course. Please tell me he won’t unleash a plague on Wyoming. Other than the millions of tons of concrete, steel and environmental destruction associated with his “world class wind park” (kind of like an amusement park, only not amusing). We have enough problems with those pesky prairie dogs and plague.

Reply to  Barbara
August 12, 2016 12:24 pm

‘Minimizing Transport of Human Pathogens Into Watersheds’
Paper on the high risk of human pathogen migration into watersheds.

george e. smith
Reply to  Barbara
August 12, 2016 1:54 pm

Well everything we have was obtained by disturbing the soil which apparently is laden with human pathogens.
So we should just get rid of everything we have and stop making more of them.

Reply to  Barbara
August 12, 2016 4:38 pm

The issue is that people should be aware of the risks involved in doing something.
Are wind turbines worth the risk to people who have to live in the vicinity of wind turbines?
Loss of water supply means a lot to rural residents.

george e. smith
Reply to  Barbara
August 12, 2016 11:14 pm

Rural residents are often farmers and have for thousands of years disturbed the soil containing human pathogens. Most farmers I know are well aware of the need for good soil conservation practices; their livelihood depends on it.

Reply to  Barbara
August 13, 2016 10:29 am

There is a difference between necessary and unnecessary soil disturbance. Food production is necessary.
IWTs are causing unnecessary soil disturbance.
Check out Vermont and California for the results of unnecessary soil disturbances from IWT installations.

Reply to  Barbara
August 13, 2016 10:34 am

There is a difference between necessary and unnecessary soil disturbance. Food production is necessary.
IWTs are causing unnecessary soil disturbance.
Check out Vermont and California for the results of unnecessary soil disturbances from IWT installations.

Leonard Lane
Reply to  TA
August 11, 2016 11:02 pm

Why do we allow slaughter of bats, songbirds, eagles, etc. by wind turbines but outlaw DDT, especially with Zika spreading. The radical leftist/watermelon mind is unfathomable with science or logic.

Reply to  Leonard Lane
August 12, 2016 6:38 am

DDT got a bum rap. It was never responsible for the deaths of raptors.

Reply to  Leonard Lane
August 12, 2016 10:22 am

Because now the environmentalists want the money from the billionaires and their wind turbines. Now it’s “save the turbines, kill the birds”. It was never about the birds…..

Reply to  TA
August 12, 2016 2:20 am

If you look at sites listing wind farm deaths of birds in the US, you will see they are not reported totals, but estimates (that would make them from models?)
And where does the data come from? From deaths at Altamont Pass, the worlds worst site for a wind turbine, where many old design wind turbines on open lattice towers, linked by electricity poles which electrocute birds have been strung across a narrow migration route in a wintering area for eagles.
No other world wind site has ever been set up with worse conditions for birds. Almost no other site like it now exists (and it is being torn down).
wind turbines are now not sited or constructed like Altamont and their sites are surveyed before building…
so wind turbines don’t now kill birds.
(If you take the supposed US eagle deaths from wind turbines against US eagle populations, you see that all US eagles have been made extinct 3 times)

Reply to  Griff
August 12, 2016 11:10 pm

Maybe my English isn’t that good but what are you saying? That all wind farms are good for birds now?
Windmills are still being build on migration routes for birds, At least in Ireland, UK and Belgium. There was an item on springwatch or autumnwatch last year and they showed birds like hen harriers being killed during migration. In Belgium new windmills will be build on another migration route.

Reply to  Griff
August 13, 2016 6:52 pm

Griff: “wind turbines are now not sited or constructed like Altamont and their sites are surveyed before building…
so wind turbines don’t now kill birds.”

Really? And you really believe that, do you?
For a self-styled environmentally concerned individual Grifter, you seem to have very little concern for the wildlife – or for the poor, sick and elderly either, judging from an exchange I had with you a while ago about deaths due to fuel poverty.
But hey, when you’re “saving the World™”, what do a few million birds, bats and bees matter? Or people, come to that?
Damn, you’re a hypocritical little so-and-so, aren’t you?

Reply to  TA
August 12, 2016 4:03 am

Does anyone ever protest locating windmills in their area?
You betcha they do TA, it’s just that the MSM doesn’t allow the truth to be told on public TV.
I’ve been a protestor. Did it make the news? nope.

Reply to  EJ
August 12, 2016 10:34 am

EJ, when you were protesting the windmills, what was the focus of the protest? Was it the blight on the landscape, or the noise, or something else? Were bird deaths a focus of the protestors?

Reply to  EJ
August 13, 2016 4:29 am

Community Health, Safety and Welfare of the Citizens. AND all of your statement, the whole kitten caboodle.
Main focus, our community. We Won.

Reply to  TA
August 12, 2016 2:44 pm

Certainly in the UK there are (some) area that are very antagonistic to bird-choppers.
There is an element of land-owner and resident.
But the self-immolating raptor-slicers do not get a free run here.

August 11, 2016 4:59 pm

With wind power varying as the cube of the wind velocity, there must be a lot of stress on the blades when the wind spikes. Can the blades be feathered that quickly?

george e. smith
Reply to  Trebla
August 11, 2016 6:17 pm

Who cares about the wind spikes ??
Those fan propellers are situated at such a tower height, that puts the top blade tip at about three times the altitude above sea level of the bottom blade tip.
The sailing cognoscenti understand that there is this thing called wind shear that makes the wind velocity a lot higher as you go up in altitude.
you don’t often get 100 MPH wind speeds at 10 microns above the sea surface.
Consequently. as the propeller rotates, at an exact synchronously locked RPM, the tip wind speed goes through a cyclic variation, from max at the top of the circle to min at the bottom of the circle, and the wing lift and drag both increase as the square of the wind velocity.
You don’t get a cubed effect (I think) because the rotation rate is absolutely constant when in operation, so you only get the square, due to the !/2 m v^2 effect.
As a result you get both a torsional (lift) and an axial (drag), or verse vicea that varies with the blade position, so the thing is designed to shake itself to pieces, as well as grind flats on the rotational bearings, and the axial thrust bearings.
As far as I know (I may not know) it is NOT possible to individually feather each blade by itself depending on its phase angle, so as to maintain exactly equal axial thrust at all phase angles, while at the same time producing exactly equal torsional torque at all phase angles.
Propeller blades do not allow such dual feathering, and the gearing complexity to feather each blade differently is just beyond imagination.
(horizontal) Wind turbines shake themselves to pieces by design. Vertical turbines don’t have that problem, and also have other advantages, such as complete wind direction insensitivity, but they have a serious disadvantage, in that they operate basically at surface level where the wind shear velocity is as low as it can get, so they don’t get as much energy out of the wind as you would like.
The exact same synchronized shaking mode infects electric trolling motors on small fishing boats. They rotate quite smoothly in air, but once in the water, with the blade tip depth varying they too vibrate themselves silly, and also scare the hell out of the fish.

Reply to  george e. smith
August 11, 2016 6:54 pm

You don’t get a cubed effect (I think) because the rotation rate is absolutely constant when in operation, so you only get the square, due to the 1/2 m v^2 effect.

The cube ratio comes about from both kinetic energy, your 1/2 mv^2 term, and also the mass that goes past the rotor per unit time, and that’s proportional to velocity so you get an extra v.
The vendors’ datasheets often have plots of output vs wind speed which show cut-in, cubic ramp up, peak output, and overspeed shutdown.comment image

charles nelson
Reply to  george e. smith
August 11, 2016 7:39 pm

Nicely explained George!

richard verney
Reply to  george e. smith
August 11, 2016 10:28 pm

The average wind speed over the oceans has been assessed to be just over BF4:
Just over BF4 is about 7 to 11 m/s (
On that basis. if max rotor efficiency is obtained in wind conditions of 12 to 25 m/s, off-shore wind farms will rarely reach maximum efficiency

Ed Bo
Reply to  george e. smith
August 11, 2016 10:39 pm

Almost 20 years ago, one of the big wind turbine manufacturers asked my team to optimize the controls for their systems. The angle of attack of each of the three blades was individually controllable with its own actuator. We were quickly able to devise an algorithm to feather each blade as a function of its angle from the ground, allowing us to optimize the generated power and significantly reduce the stresses.
I haven’t been involved in the field since then, but if it was that easy two decades ago, I presume it is pretty common now.

Reply to  george e. smith
August 11, 2016 11:39 pm

Propeller blades do not allow such dual feathering, and the gearing complexity to feather each blade differently is just beyond imagination.

Actually, helicopters have a similar problem.
When the helicopter is moving forward at speed, one side of the rotor is moving forward into the wind and the other side is moving backward with the wind. In other words, the two halves of the rotor experience different airspeeds. To compensate for this the helicopter has a control called the cyclic which changes the pitch of the rotor blades individually. Thus the lift of both sides of the rotor is kept equal. cyclic
Once we’ve solved the problem of getting equal lift over the whole rotor disk, we can pitch the rear of the rotor more, causing more lift on the rear, causing the helicopter to pitch forward and move in that direction. Well, that’s what you’d think. Actually, because of the gyroscopic effect the cyclic control acts on the rotor blades at a right angle to the direction you think it should be. swashplate

Reply to  george e. smith
August 12, 2016 4:06 am

Gotta love those deadly machines.

Crispin in Waterloo
Reply to  george e. smith
August 12, 2016 4:11 am

george e.
“As far as I know (I may not know) it is NOT possible to individually feather each blade by itself depending on its phase angle…”
In 1977 I was visiting Dr Peter South at NRC in Ottawa, he of the 2-arm Miquelon Island Darius Rotor fame. While I was there a young long-haired enthusiast pitched up with a hand-built mahogany Darius rotor with three straight, rigid blades which articulated about their mounting points and had springs to pull them into ‘standard’ position. I have always presumed he placed the mounts 22% of the total length in from each end of the three blades. The blade profile was NC 1000 or 1001. When the pull on the blade exceeded the spring pressure, which happened at certain points during one complete turn, that blade rotated relative to its mounting point.
This means that the blades did in fact feather individually and did so not from a swashplate position by force, but freely per load and wind direction at the time. Peter (and I, for what that is worth) didn’t think much of this from a power generation point of view, however it did have a very interesting (and intended) ability: it self-started.
The point of a self-starting Darius rotor is that it overcomes the need to have a wind sensor, timer and motor (often, in those days, a VW generator and battery) that started it spinning if the wind was sustained and fast enough. At the time there was a 3m diameter rotor on top of Ryerson Collegiate in downtown Toronto making a lot of noise that was started by just such a system. The enthusiast had devised a method of getting a small Darius rotor to start by itself which is interesting because they inherently do not.
Peter advised thus guy and his friend, after seeing it in operation on the lawn self-starting as claimed, that this was not an advantage on a power generating mill. Why? Because it is much more advantageous to have a system that started when you wanted it to, not automatically when the wind blew. At the time they were building 2 MW generators on the St Laurence River islands and they were picky about how the rotor was positioned when they were doing maintenance. He said, for example, that the maximum stress on the blade occurred when the pair of blades (about 2 feet wide) were facing the wind in the 12-6 o’clock position, The least stress was in the 3-9 o’clock position even though it generated torque (a bit) in that orientation. All the down time was done with the blades oriented into at 3 o’clock and away from the wind at 9 o’clock. I was surprised that this was an issue at all assuming that the big problems were when it turned quickly. These mills had two horizontal supporting arms that were mounted about 20% towards centre from the top and bottom. These it turned out were only ‘doing anything’ when the mill was stopped. They held the blades up when they weren’t turning, that’s all.
The Canadian NRC was at the forefront of Darius rotor design for many years. Some other time I will tell the story of how one of the Canadian 3m tall rotors destroyed the wind tunnel in Pretoria following an argument between the engineers (who already knew everything) and the academics (who didn’t know enough to be allowed to operate their own toys).

Alan Watt, Climate Denialist Level 7
Reply to  george e. smith
August 12, 2016 11:01 am

Wind turbine rotation is phase-locked? I thought it had to be variable, and the electrical output was phase-shifted to match the grid at the interconnect?

george e. smith
Reply to  george e. smith
August 12, 2016 2:30 pm

Well Ed Bo says individual blade feathering is feasible; well in this computer age, it should be possible in principle to change anything almost any way you want to.
So that works for me Ed, does leave one query though, I can see that one could feather a fixed design propeller so as to flatten out say the torque (lift) characteristic of the prop, or if one chose to flatten the axial thrust curve one could do that, but is it possible to flatten them both at once.
And Commie Bob also mentions the egg beater rotor problem. My one ride on a helicopter from the top of the Pan Am building in NYC out to Kennedy airport, made me a confirmed fixed wing fan. I’m thinking I might actually have taken one from Wall Street out to Kennedy as well. Seems as though I might have had family with me on that one.
So I’ll take it that there are some workable fixes for the wind shear variations.
That’s why we all come here; to pick the brains of those folks that know this stuff.
I’m not convinced on Ric Werme’s explanation of a cubic relationship.
The air mass is accounted for in mv the momentum of the air mass. The thrust or lift comes in as the square due to the rate of change of the momentum. In the case of a sail driven vehicle the vehicle speed increases as well.
I don’t see the power applied to the rotating shaft being cubic, if the rotation speed remains fixed.
And the curve in that plot looks rather parabolic to me.
So I’m skeptical, but capable of being educated.
In any case, it is a serious impediment to have such a strong variation factor.
At least with hydro-electric, they pretty much have water velocity under control.
The electric trolling motor shaking I do know, since I have one of those in my closet, and my son has one on his fishing skiff, and since he’s the skipper, I get to be the deck hand, so I’m the one who manages the electric trolling motor, so I experiment and run it as deep as I can without touching the bottom (of the pond).

Reply to  george e. smith
August 13, 2016 9:54 am

George, check out when you get a chance.
It confirms the v^3 power curve and has a more rigorous derivation. It also has a lot about turbulence.
I couldn’t find a table of wind speed and power output, but before I posted that graph, a couple points seemed to fit a cubic curve pretty well.

Reply to  george e. smith
August 13, 2016 6:20 pm

It is surprising how few people truly understand what a dirty load any sort of fan or pump rotor can impose on its coupled components. Cavitation in particular can destroy pump impellers, fans and – I strongly suspect – wind turbine blades and their accoutrements in a surprisingly short time…

August 11, 2016 5:00 pm

Is the fishing under a wind tower better? Have the mackerel and sardines learned to school there so the propellers can wack the heck out of predatory birds and provide chum and crap bait?

Reply to  fossilsage
August 11, 2016 5:42 pm

Fishermen lose opportunity in the squatter land grab. Trading valuable habitat for these things that work well on the land, where everyone can enjoy them.

Reply to  borehead
August 12, 2016 1:36 am

They work well on land? When did this happen?

Reply to  borehead
August 12, 2016 10:27 am

This was a comment on a blog I was reading (I don’t recall where from)
“Hikers aren’t permitted around there because towers are DANGEROUS TO PEOPLE, especially if you don’t know what you’re doing. High altitude icing on blades can crush a car once it’s ejected off a blade, let alone a human. High voltage switch gears will fry an individual. And then there’s always the worry of copper strippers, not a few of which have cut locks and torn apart towers, and not a few of which have fried themselves trying to cut energized equipment.”
I don’t know if this applies to offshore or not (hopefully not copper strippers, but who knows), but it was a very interesting comment. Not sure anyone would be allowed under the offshore turbines, though I did read that Denmark was trying to get technicians to live in the nacelles so it was easier to maintain the turbines. Otherwise, you have to send them out in boats to fix the turbines. It’s costly and time consuming.

Reply to  borehead
August 12, 2016 1:47 pm

For some reason when you started talking about copper strippers, I immediately thought of exotic dancers.

Reply to  borehead
August 12, 2016 3:08 pm

Mark W
Not imbibing when I read yours . . .
Saved a keyboard at least!
Auto – Can I buy you a beer if in South London?

Reply to  fossilsage
August 12, 2016 2:23 am

wind farms do offer a marine sanctuary for fish, since fishing boats keep clear.
Seals have learned to use these areas because of all the fish…
Danish research conducted with lidar to track sea birds at an offshore site on a migration route shows the birds avoid the turbines.
They estimate the deaths a less than 1 in 200,000 passing birds per wind farm.

Mickey Reno
Reply to  Griff
August 12, 2016 7:36 am

Seals have learned to use these areas because of all the fish…

Griff, in your apologia, you tend to be quite selective. Please read more carefully. The article does NOT say that. It says the seals are hunting in an area they already used (shallow sandy bottom) which also happened to be convenient for tower construction. It says the researchers now intend to study whether or not the prey base has increased. It’s possible that if human fishing decreases in this area, that would be to the advantage of the seals, both leaving more fish for the seals, and not scaring the seals away with boats and their motors and propellers (a not-uncommon cause of seal deaths). It’s also possible that the towers are harming the seals, possibly reducing their range, and the possible impacts of low frequency sound waves, etc. It specifically says they need to study whether or not the prey base is increasing or decreasing in these areas, and if environmental health has been harmed in the long term.
Also, the Danish research to which you refer is not part of the BBC article. Did you intend to give a link, or did you just want to make a bold assertion of 1 in 200K birds dying, but giving the impression of an authoritative source (not that I consider any BBC news report as authoritative)?

Reply to  Griff
August 12, 2016 8:49 am

Mickey – that was just a convenient article summarising the seal findings. There are more online.
Here’s the Danish research – see ‘Summary’ section

Mickey Reno
Reply to  Griff
August 12, 2016 10:54 am

Thanks for the link. I read through the paper. They have tried to be thorough, and I can’t fault their methodology, given the scope and complexity of the issue. It’s important to understand that this study didn’t actually count bird strikes or physically document deaths, only bird presence. Their hypothesis was to perform a before and after analysis of bird count patterns to test one of three premises; 1 that wind turbines would scare birds away where they had previously been seen, 2, that wind turbines would attract birds where they had not been seen, or 3 that wind turbines would have little overall effect on bird counts. The study shows a general tendency toward avoidance. That’s good.
But the avoidance behavior appears to be species dependent. And their data collection has big holes. It was sporadic, covered large areas, there was large annual variations, they depended on radar and human eyes estimating from aircraft (did the aircraft’s presence color the sample?), and perhaps most importantly, even with radar, they could not count small birds or bats. So, their impact ratio in the conclusion, while very low, is not altogether persuasive to me. It is so low that even if it doubled or tripled, it would still be very low. I would guess that the real number is higher, because their ratio was based on a purely mathematical determination of the odds of a direct strike of a bird flying through the area covered by a spinning turbine blade, as determined by those species which don’t have avoidance tendencies. They don’t consider the effect of pressure drops near the spinning blades on a bird’s (or a bat’s) lungs that might kill it even if not impacted directly by the blade. And they couldn’t study or count small birds or bats due to their limited counting methodology. They need to focus on the attractive aspects of the towers, to count species which would seek to use them to roost or nest, or which, at night, due to their safety lights, attract bugs or nocturnal birds or bats. They should net some areas and actually try to catch some small bird corpses around the turbines and autopsy those birds.

Reply to  Griff
August 12, 2016 11:20 am

You’re doing fine.
Keep up the good fight to bring some facts to the unbelievers that haunt the WUWT halls.
I won’t be able to join the battle until later this evening in California.
Offshore wind power is the future. The facts are irrefutable.

Reply to  Roger Sowell
August 13, 2016 5:55 pm

Roger Sowell: “Offshore wind power is the future. The facts are irrefutable.”
Wrong. What is irrefutable is that offshore wind power is a dead end.

Reply to  Griff
August 12, 2016 1:50 pm

You guys are using a different definition of “facts” than does the rest of humanity.

Mickey Reno
Reply to  Griff
August 12, 2016 8:22 pm

Roger Sowell, that’s some dang good cheer leading! At the risk of going completely off-topic, I beg your indulgence and let me show you how I do it.
Yes, by all means, please come back later and give us your best shot. Please participate in WUWT. Read lots of articles. Read some comments, too, if you can stand it. At WUWT, you can learn about the water cycle, ENSO, energy density, climate feedback, GCM weaknesses, economics of renewable energy, economic opportunity costs, natural climate variability, biological adaptation and population health in butterflies, polar bears and walruses. You can also learn ALL the contents of the IPCC studies, not just the summaries. Learn how propaganda, groupthink, polemics, noble causes, post-normal science, scientivists, and financial and/or political corruption are viewed by people who aren’t professionally committed to “the cause,” who really do read science papers, who see some up side to giving plants more food, who know the poles aren’t melting, who understand climate change on geologic time scales and who aren’t afraid of the Antarctic ozone hole or a one degree warmup.
I make you a solemn promise, that if you disagree and if you have a case, you will get a fair hearing here, a far more fair hearing than most of us would get at RealClimate (I am banned and don’t even show up in the Bore Hole) or The Guardian (they want to put me in prison) or NPR (they need people like you to fund them, and don’t dare pissing you off). Finally, as a little social media style test, go up to the WUWT blog roll and note that Anthony is happy to include RealClimate, Tamino, ScienceOfDoom and even crazy SS kidz on his blog roll. I invite you to visit those sites and try to find even a hint of reciprocity. Then think about how your statement about “unbelievers” makes you look.

Reply to  Mickey Reno
August 13, 2016 6:00 pm


Reply to  Griff
August 13, 2016 7:26 am

For Mickey Reno, you are hilarious.
I suggest you read my writings and especially my speeches. Or even search WUWT for my name. Anthony has graciously allowed me a dozen or so guest posts over the years. One or two memorable ones involved Michael Mann and his mis-adventure at Disneyland.
Or you could go on insulting people, which shows you have no clue what you are talking about.
Your move, Chief.

August 11, 2016 5:02 pm

crab! crab crab

August 11, 2016 5:10 pm

So one upshot is that Cape Wind (if built) will endure more wind stress and rapid fluctuations than previously anticipated. This study seems to be a welcome “look before you leap” type of exercise.
Cape Wind seems to be a classic contest between two opposing groups of environmental activists battling it out. The outcome will not be decided by either group, but instead by whether enough taxpayer/ratepayer monies can be funneled to politically connected insider investors.
Physical data bearing on the viability of the project, like this study, is interesting but will play no role in the outcome.

Reply to  TonyL
August 11, 2016 6:07 pm

Cape Wind may end up costing more than the “Big Dig” and not provide enough power to even light that tunnel!

August 11, 2016 5:29 pm

“the cost of more stress on the turbine’s blades”
Not to mention more stress on the bearings and gearboxes, which are already pretty much at the absolute limit of engineering knowledge – or, if a friend of mine who specialises in rebuilding the gearboxes is to be believed – somewhat beyond.

Crispin in Waterloo
Reply to  catweazle666
August 12, 2016 4:58 am

Siemens agrees with your friend.

August 11, 2016 5:37 pm

I’d be very surprised that companies like Dong Energy that are working on projects to build and operate wind farms in the study area have not surveyed the areas of their leases, and found the winds suitable. They are poised to invest many millions. Without verifying the wind environment? I assume they have, and don’t share Dr Archer’s concerns.

richard verney
Reply to  Gamecock
August 11, 2016 10:31 pm

Windfarms are subsidy farms.
Efficiency is not an important issue. The operator merely needs to make sure that the subsidy keeps on rolling in.

Reply to  richard verney
August 12, 2016 4:35 am

‘Windfarms are subsidy farms.’
Dong is an experienced off shore wind farm builder. Your comment shows cynicism, not insight.

Reply to  richard verney
August 12, 2016 3:22 pm

Gamey old pal,
Dong still takes subsidies.
As if it would not . . . . . . .
Did I see, above, someone (reporting??) suggestions that technicians LIVE in the towers?
FFFS Madness.
About one thousand, three hundred and seventeen times worse than going to sea!!!
My model told me so.
Auto – well aware of the conditions at sea.
Those make maintenance and repair somewhat more problematic than on TERRA FIRMA.
Maybe it can be done – but at a cost . . . .

Reply to  richard verney
August 12, 2016 7:14 pm

Taking subsidies affects their competency at building offshore wind facilities how?

August 11, 2016 5:55 pm

More evidence of the useless task of trying to harness and unharnessable, unpredictavle and unreliable power source. Reminds me of Don Quixote and so do wind enthusiasts, who are full of hot air and are mostly bags of wind.

Ross King
August 11, 2016 5:58 pm

I’ve said this before and will say it again….
Some years ago, travelling across the high Moors of Lancashire/Yorkshire on a windy day, a very high proportion of the innumerable (unsightly!) windmills were standing idle (‘feathered-out’??). We stopped at a village pub and asked the Landlord why they weren’t all producing to the max.
“Nay! wind’s too strong. They ‘ave to feather ’em out lest they blow themselves up!”
Yes, it was windy, and yes, we had stopped for a refreshing hike, but no, it wasn’t *that* windy….. certainly not a gale. What a farce!

Reply to  Ross King
August 11, 2016 7:42 pm

I am still not exactly clear on why these things cannot be geared to adjust to higher winds when they exist.
Is it just too expensive and thus not worth it, or is it technically undoable?

Reply to  Menicholas
August 11, 2016 10:11 pm

Yes, it is essentially and practically too expensive to build them strong enough to withstand those forces they get at high winds while still operating. Ric W. went into good detail about the difference n forces as the blade rotates that cannot be avoided. (low at the bottom of the arc, highest at the top of the arc. That pressure cycle (low-jerk-low-high, low-jerk-low-high, low-jerk-low-high, low-jerk-low-high, low-jerk-low-high, low-jerk-low-high, repeat every 10 seconds for the rest of the year)
(The jerk happens as the lowest blade traps the turbulence as it passes the tower behind the blade.)
So prudent designers design the mechanical parts to withstand as much stress as they can afford, then feather the blades to prevent higher stresses at higher winds. Then they hope the controls work. Now, the problem happens in the rest of the grid. Wind is (sort of) expected, and the grid operators can plan a day as the local winds rise. Hopefully, they rise slowly and uniformly, and the grid plans on shutting down gas turbines as it rises.
But if the wind gets near the “cut off” point of high winds, this wide area of maximum production from the wind turbines immediately and suddenly ALL trip off. BAM! The load must get moved immediately to some (no longer running!) gas turbines. A few minutes later, the wind is still high, but gusts “are low enough” for a few minutes. BAM! All of the area’ wind turbines are back producing again … for a few minutes. Demand goes back to zero for the previously strained gas turbine. For a few minutes. And the gas turbines are breaking themselves to bits.
Then again, the wind turbine builders and operators build them FOR the subsidies of the “number constructed” – NEVER the “number operating” nor the “life time power produced.” Once constructed, the subsidies and tax breaks for construction go away, and so most of the time they are left to slowly degrade into rust and destruction.
At Altamonte Pass, most of the turbines present are rusted and cannot produce power. Removal and replacement is a constant process.

Reply to  Menicholas
August 12, 2016 8:59 am

Thanks RA!

August 11, 2016 6:11 pm

Offshore wind is a total joke. The sea is an incredibly hostile environment for machinery – corrosive, buffeting, a biological soup, each of which works to rapidly break down and destroy artificial structures.

Reply to  Eric Worrall
August 11, 2016 7:40 pm

It would seem like only a matter of time before a storm blows in that wrecks the entire wind farm.
Are these things insured against storm damage?

John of Cloverdale WA Australia
Reply to  Eric Worrall
August 11, 2016 10:26 pm

Yes Eric, as we see here with the Port Kembla Wave machine. Left to rot in the ocean, as the directors milked the subsidy teat and then declared bankruptcy. Most probably they are directors of another Green Company, back on the teat again.

Reply to  Eric Worrall
August 12, 2016 8:42 am

Just think of all those oil and gas rigs that might fall into the sea as a result…

Reply to  Griff
August 13, 2016 7:57 am

Offshore drilling platforms can withstand weather conditions far in excess of anything that would happen in reality (e.g. 100 years of hurricane-force winds). When you need a structure to absorb the vibrations of a giant drill bit, you don’t mess around.
So your attempt at a pithy nitpick falls flat on its face.

Reply to  Griff
August 13, 2016 3:22 pm
It has happened on land. What precludes it from happening at sea?

August 11, 2016 6:16 pm

If this here to unknown “turbulence” was not in these models is it in the Global Warming prediction models? If not, what does this do to these models? Seems to me the science is far from settled.

Reply to  usurbrain
August 11, 2016 6:55 pm

Cape wind off cape cod is dead, even after giving 40,00 to sen markey, our resident green scammer

Pop Piasa
August 11, 2016 6:19 pm

So, some coastal wind farms are in better places than others? Those “best” locations can change too, over time. Until we understand the whole system, we won’t know where the stable and reliable wind is. Still, what about the seabirds?

Reply to  Pop Piasa
August 12, 2016 8:53 am

See my reply to Mickey above…
Seabird movements are usually in a defined ‘band’ just offshore… thought there are also feeding ares to take into account. windfarms are sited to avoid areas used by the birds – in the UK a one year independent assessment needed as part of the planning and I know of at least 2 windfarms cancelled due to potential bird impact if built

Reply to  Griff
August 12, 2016 9:01 am

OK Griff, we get it: You are an apologist the wind industry.

Tom Halla
August 11, 2016 6:22 pm

Yet more evidence that bird choppers are not a simple panacea. Perhaps pulling subsides from them is overdue.

Pop Piasa
Reply to  Tom Halla
August 11, 2016 7:15 pm

More like pandora’s box than a packaged panacea to me.

August 11, 2016 6:24 pm

Here’s an article, okay, propaganda piece, designed to make coastal Mainers proud that their state is being used to power southern New England. It also goes off on a tangent to praise the state AGs who are protecting us from big, mean Big Oil.
It’s relevant here because it has a photo of the Deepwater wind project.

Pop Piasa
Reply to  Ric Werme
August 11, 2016 7:28 pm

Ric, that picture gives me an idea. Why not put wind turbines on oil rigs? (hee hee)

Reply to  Pop Piasa
August 11, 2016 9:50 pm

Because the weight of the turbine plus the structural steel to support it and it’s forces would be impossible to add to existing platforms. Designing new oil/gas platforms to include turbines would similarly, I’m pretty sure, be cost prohibitive. Besides, a large platform often runs 2 to 4 gas turbines for about 20 to 80 MW, whereas the wind turbine only produces about 4 MW. Just a bit of a mismatch.
Besides, do you want to be on a crew helicopter landing next to a monster wind turbine on a story night?

Reply to  Pop Piasa
August 11, 2016 9:51 pm

Oops, should be stormy night…and a problem would be a sad story.

Eugene WR Gallun
August 11, 2016 6:25 pm

We have been missing out on hurricanes in the south and nor’easters in the north — but Boreas will return and he will huff and puff and blow their windmills down.
Eugene WR Gallun

Pop Piasa
Reply to  Eugene WR Gallun
August 11, 2016 7:34 pm

I think their houses are built on meteorological sand which will blow away with time.

August 11, 2016 6:39 pm

Oh what the heck. This is a good excuse to rerun what I think is the most informative wind turbine photo ever. It’s even offshore, I think in the North Sea.

Reply to  Ric Werme
August 11, 2016 7:36 pm

Ric, can you inform us who be less astute exactly what it is that this picture is informing us of?

Jeff Hayes
Reply to  Menicholas
August 11, 2016 8:00 pm

At a guess (and as a layman) I’d say that weather conditions that day were perfect to show the vortices and turbulence caused by the WTs. Only the most upwind turbines (in the foreground) are operating at maximum efficiency for the given wind, being in undisturbed air. All the rest, being in disturbed air, are less and less efficient, the further downwind in the array they are, reducing the total overall efficiency of this wind farm. The total output will never be near the maximum rated output for all the turbines, and this will be true no matter the wind direction because of the layout of this farm.
How did I do?

Reply to  Jeff Hayes
August 11, 2016 8:16 pm

Jeff Hayes.
Accurate analysis. A windmill must be 10 rotor diameters behind the previous wind turbine to begin generating 90 – 95% percent rated power. About 4-6 rotor diameters sideways – if the two wind mills are perpendicular to the wind.
A bigger wind turbine requires more space between turbines, so the net “power per square kilometer” of ground space remains about the same for turbines over 1.0 Megwatt rated if you try replacing the old turbines. (170 kWatt delivered on average).

Jeff Hayes
Reply to  Menicholas
August 11, 2016 8:13 pm

I forgot to add that adding more turbines to this farm, while it might slightly increase the output of the farm, will actually decrease the overall efficiency even further, and so on…

Reply to  Menicholas
August 11, 2016 8:28 pm

Those are Ƈhem Ʈrails !

Reply to  Menicholas
August 12, 2016 6:51 am

I’m guessing that water vapor in the air was at the saturation point. There’s a low pressure area behind the wind mills that causes the air to cool just enough for vapor to form.
Would this be a new form of negative feedback?
As CO2 levels go up, more wind farms get generated.
Wind farms cause an increase in local cloudiness.
Clouds reflect sunlight back into space cooling the earth.

Reply to  Menicholas
August 13, 2016 10:04 am

Menicholas, the other comments on this photo pretty much say everything there is to say. I didn’t say much due to time pressure, but I was confident others would help out.
One thing folks missed is that this actually has some useful information for land based turbines too. Those built in crop land change the environment at night from an air inversion that keeps surface winds low and humidity high. Instead, the turbines mix out the boundary and instead bring increased evaporation at night. In dry conditions farmers will have to increase irrigation.

Curious George
Reply to  Ric Werme
August 11, 2016 7:52 pm

Someone should Photoshop those fog trails black, just like a steam from a cooling tower.

Reply to  Curious George
August 12, 2016 1:57 pm

It’s possible, of course. But I think I’d go with what my old high school physics teacher said, that when you remove energy from a system, the system cools. So I’d say that the cooler air downwind from the windmills is cool enough to cause some condensation, i.e. fog.

Reply to  Ric Werme
August 11, 2016 7:54 pm

Great photo! How do we know these windfarms don’t have a negative impact on our climate?

Jeff Hayes
Reply to  Andsim.
August 11, 2016 9:03 pm

I was going to go for humor but after thinking about it, I realized that in any system where one form of energy is converted to another there are losses, usually in the form of heat. In the wind farm pictured above we have friction losses from air friction warming the turbine blades (heat), electrical heating from current flow in the generator windings (more heat), friction losses in the mechanical bearings (yet more heat) and slowing of the airflow through and downwind of the turbines, which in this case are over water, so the rate of evaporation and the resultant cooling of the surface from the evaporation/transpiration cycle is reduced causing retained (even more) heat. The inescapable conclusion is that wind farms, especially over water, contribute to global warming. Whether this is a negative or positive impact on the environment probably depends on your point of view.

Rainer Bensch
Reply to  Andsim.
August 16, 2016 2:34 am

Jeff, you forgot the heat produced by the consumption of the electricity at the end-user’s site. Much much more heat.

Reply to  Ric Werme
August 13, 2016 8:22 am

All those neat straight rows remind me of the starting line at a NASCAR event. Only in this case, the slipstream factor is hindering the progress of those behind the leaders, not helping.
Just about any NASCAR fan could tell you about slipstreaming and how the racers use it, even if he or she couldn’t explain the actual physics involved. Migratory birds know about it too; they fly in formation for a reason. Apparently, whoever green-lighted the layout for that wind farm doesn’t know about it.

Joel O'Bryan
August 11, 2016 6:44 pm

” Having three separate pieces of evidence that support the same finding allows us to be confident that there is something special going on,” she says.”

I am quite skeptical of this claim there is anything “special” about the turbulence in Cape near-shore marine wind flows. Probably more like “unexpected” (because we’ve never studied it with this much measurement detail), but likely the rule rather than the exception. At least where there have been noted near-shore wind fields economically worth harvesting for electrical generation.

Reply to  Joel O'Bryan
August 11, 2016 10:03 pm

From what sailors have told me,the wind pattern around Cape Canaveral is very confused. Difficult to sail around heading south.

Gary Pearse
August 11, 2016 6:56 pm

So an associate professor of environment and prof of geography are designing wind farms! In Canada that would be against the law. I thought engineers must be distancing themselves from much of the foolishness in this activist domain. Just as there is no such animal as a rocket scientist, there are no windfall designer scientists. Or perhaps in postnormal science engineers are no longer relevant. How hard can it be? I can here them say.

Gary Pearse
Reply to  Gary Pearse
August 11, 2016 6:57 pm

Windmill, drat android correctors.

Pop Piasa
Reply to  Gary Pearse
August 11, 2016 7:42 pm

Perhaps windfall is actually most descriptive?

Reply to  Gary Pearse
August 12, 2016 4:43 am

She has degrees in civil engineering.

August 11, 2016 7:39 pm

So these “Experts” can’t figure out why it is called Cape Wind? The nuts/kooks have taken over the asylum!

Pop Piasa
Reply to  Justthinkin
August 11, 2016 7:46 pm

If only it had been named “Cape steady Breeze”…

August 11, 2016 9:18 pm

The wind around a relatively open region, like Cape Wind, is much more turbulent than around a relatively enclosed region, like the Baltic Sea.
Gee – who da thunk?

Reply to  Analitik
August 11, 2016 10:57 pm

In case anyone doesn’t know Massachusettscomment image

John of Cloverdale WA Australia
Reply to  Analitik
August 12, 2016 1:32 am

Analitik, the Bee Gees had never been to Massachusetts when they wrote their hit song in 1967. Love them or hate them, we Aussies claim them as ours.

Reply to  John of Cloverdale WA Australia
August 12, 2016 5:30 am

And I doubt Deep Purple had ever been to Kentucky:

August 11, 2016 9:40 pm

I always thought the song “Ripple” was about the cheap wine I drank once or twice while in the Navy, but it’s about ripple in still water (no wind to blow). I’m sure they weren’t thinking about windmills then with “nor wind to blow”, but who knows:
It’s not about Ripple Wine (as I stupidly thought) – some quotes from the song:
Ripple in still water
When there is no pebble tossed
Nor wind to blow
“Let it be known there is a fountain
That was not made by the hands of men”
“You who choose to lead must follow
But if you fall, you fall alone”
Ripple Lyrics – you can follow along:
If my words did glow with the gold of sunshine
And my tunes were played on the harp unstrung
Would you hear my voice come through the music
Would you hold it near as it were your own?
It’s a hand-me-down, the thoughts are broken
Perhaps they’re better left unsung
I don’t know, don’t really care
Let there be songs to fill the air
Ripple in still water
When there is no pebble tossed
Nor wind to blow
Reach out your hand if your cup be empty
If your cup is full may it be again
Let it be known there is a fountain
That was not made by the hands of men
There is a road, no simple highway
Between the dawn and the dark of night
And if you go no one may follow
That path is for your steps alone
Ripple in still water
When there is no pebble tossed
Nor wind to blow
You who choose to lead must follow
But if you fall, you fall alone
If you should stand then who’s to guide you?
If I knew the way I would take you home
La da da da … la da da da da ……

Just for a musical interlude…

August 11, 2016 9:58 pm

“Is something special going on in the North East?”
Yes. Assumptions were made and not validated.

August 11, 2016 9:58 pm

Pretty obvious that offshore winds will be stronger. You get Javier Stokes at the surface boundary, voila, turbulence.
Nullschool gives valuable lessons of relative wind strengths ocean vs land:comment image

richard verney
August 11, 2016 10:37 pm

Why do you re-fill a water pistol when it runs out of water?
Because there is little energy in displaced air, whereas there is useful energy in displaced water.
There is little energy to be harvested from the wind. It is also variable and above all unpredictable. These facts, coupled with the fact that there is presently no practical means of storing energy, would tell any engineer that this is not an energy source capable of powering forward the 21st century. There is a reason why our forefathers abandoned windmills in the 18th and 19th centuries, and sail power in the 19th and 20th century.
The way to the future is not to go backwards to the past.

Leo Smith
Reply to  richard verney
August 11, 2016 11:18 pm

tell any engineer that this is not an energy source capable of powering forward the 21st century.
engineering is no longer done by engineers, but by politicians accountants and dreamers.

Reply to  richard verney
August 12, 2016 2:26 am

18% of all UK electricity was provided by wind in December 2015…

Reply to  Griff
August 12, 2016 3:20 am

A valid point Griff , but you are not telling the whole story are you.
The summer months tell a different story :
During May , June, July the winter winds dropped to the point where at times in May, June and July the metered windpower fell to 10%, then 3% , 1% , and on at least one occasion,0.1% of demand .
Meanwhile nuclear power chugged on , delivering 6-8GW no matter what the weather was doing.
No one question that windpower under the right conditions can make a significant contribution to UK demand but it is unreliable at present, benefits mainly just a few of the population and at present, IMO, cannot alone be the basis, or even the major component, of a modern , power hungry society.

Reply to  Griff
August 12, 2016 8:43 am

summer is for solar…
and in any case we have been getting more power from wind than coal this summer, now the coal plant shut down has begun

Reply to  Griff
August 12, 2016 10:29 am

Griff: Glad it’s you. When it’s dark and stormy for a month, there won’t be any power, except the diesel generators, which every country and island using solar and wind have for backup. And they use those generators sometimes half the time. How much do diesel generators pollute?

Steve T
Reply to  Griff
August 13, 2016 3:59 am

August 12, 2016 at 2:26 am
18% of all UK electricity was provided by wind in December 2015…

Wind and solar are akin to the following scenario:
You have a car sitting in your driveway and you want to go somewhere but don’t feel like driving or you know it may be very difficult to park nearby. So you ring up and you are lucky there is one available immediately.
As a one-off this might be convenient, if a tad expensive, given that the cost will be far more than the fuel cost. Yes, I know that there are other costs involved in running a car, but you’ve already factored those into the need to have a car for work etc.
Now, how would you feel if the government made it a requirement to always use a taxi if one was available (your car being monitored for use against a taxi phone-in database) resulting in much lower usage of your car (despite the fixed costs) and extra costs for taxis.
This is equivalent to the current situation of renewables and the current mandates.
Does it make sense?
Who gains?
In one situation it is the wind and solar operatives/landowners, the other would be taxi owners/drivers.
The losers – Joe Public. Because it is an expensive (semi-compulsory) duplication of a cheaper solution to the requirement for transport.
What do you think would be the situation with regard to the numbers of taxis and taxi firms – yes a massive increase in the number of vehicles registered. Imagine the waste in terms of duplicate costs of manufacture, insurance, regulation etc. all for something not actually required.

Steve T
Reply to  Griff
August 13, 2016 4:13 am

Oops,So you ring up FOR A TAXI and you are lucky there is one available immediately.

Reply to  Griff
August 13, 2016 8:19 am

And what was the percentage of consumption of that 18% ? And was all backup shut down during the generation of that 18%?

August 11, 2016 11:22 pm

Too pre-post-modern. Don’t you know the climate white elephant needs to be built first, and the basic information on why it’s an obvious white elephant should come later? Prudent forethought is so last century.

Jeff Hayes
August 11, 2016 11:42 pm

Some video to share with your favorite wind-energy fan:

Oh the schadenfreude…

Reply to  Jeff Hayes
August 12, 2016 2:24 am

The number of those which happen each year is astronomically small. share that with wind farm opponents…

Reply to  Griff
August 12, 2016 3:05 am

“astronomically small” is also the answer to such questions as
How many people want a wind turbine near their home
How many wind turbine farms are constructed without subsidy
How many green programs would exist without political insanity

Reply to  Griff
August 12, 2016 6:58 am

When dealing with a power source that is already uneconomical, even “astronomically” small is too much.

Reply to  Griff
August 12, 2016 8:40 am
“The CWIF recorded a total of 1,328 accidents involving wind turbines between 1995 and 2012. Of those, 200 involved fire. There have been no recorded fatalities and four recorded injuries from wind turbine fires, the IAFSS report says.
That’s 11.7 fires per year on average, or nearly one a month, the research points out.
While that might sound like a lot, in 2012 there were 225,000 wind turbines installed globally, according to trade association the Global Wind Energy Council. That means you could expect there to be one fire a year for every 19,230 turbines operating worldwide, on average.”

Reply to  Griff
August 12, 2016 5:01 pm
Reply to  Griff
August 12, 2016 11:04 pm

And how many coal or gas turbine fires (or other incidents which destroyed an entire generator) were there during that time?
How many nuclear plant accidents?
And Griff, your stats are way off. In the last year mentioned, there were far more turbines than in the first year.
You cannot take the average incidence over 17 years and apply that to the number of plants in operation in the final year, when for many of those years the number of turbines was far lower.

Reply to  Griff
August 13, 2016 10:10 am

In the US, and I think Canada, and probably most anywhere else, turbine fires don’t have to be reported. We really don’t have a good idea how many there are. From that Caithness link:

Data in the detailed table attached is by no means fully comprehensive – CWIF believe that what is attached may only be the “tip of the iceberg” in terms of numbers of accidents and their frequency. Indeed on 11 December 2011 the Daily Telegraph reported that RenewableUK confirmed that there had been 1500 wind turbine accidents and incidents in the UK alone in the previous 5 years. Data here reports only 142 UK accidents from 2006-2010 and so the figures here may only represent 9% of actual accidents.

Reply to  Jeff Hayes
August 12, 2016 2:55 am

Many more on youtube. Note the most popular popup selections on youtube search after entering “wind turbine” are
wind turbine fire
wind turbine explosion
wind turbine accidents
wind turbine failure
wind turbine noise

Reply to  Jeff Hayes
August 12, 2016 9:05 am

This puts a new ‘spin’ on the old phrase ‘fanning the flames.’

August 12, 2016 1:35 am

“It’s important to ensure that science doesn’t underestimate the possible wind resources,”
I think this would be more appropriate: “It’s important to ensure that science doesn’t overestimate the possible wind resources”

August 12, 2016 4:02 am

They should have consulted yachtsmen first. Any yachtsman would have told you that the wind is ALWAYS more unstable around a headland, and Cape Wind sounds as if it is a headland.

Rob Dawg
August 12, 2016 4:04 am

I guess near on four centuries worth of seafaring sailing ship’s logs of conditions in the exact area weren’t available for inclusion in the report.

Ian Macdonald
Reply to  Rob Dawg
August 12, 2016 5:28 am

+1 Aaaargh, they be available, just they be saying things the greenies might not want to hear, matey…

Bruce Cobb
August 12, 2016 5:53 am

Who cares? As long as Big Wind makes their dough, that’s what matters. Cape Wind was doomed from the start because of NIMBY politics. Opponents are nothing if not rank hypocrites. They love “green” energy, just not where they might have to look at it.

August 12, 2016 6:04 am

Interesting photo of the downstream conditions from a windmill. It is the only one that verifies of the weather modifications downstream. That’s what I complain about. There are no studies of the downstream areas. Unlike windbreaks, trees in a row, does this help the local area, or create problems. Does the turbulence change the local weather? How about, further downstream, or, the upstream pooling effect? If you block the flow here, does the wind blow heavier there? Man-made global warming created by ducting the winds?

Reply to  Jim
August 12, 2016 10:32 am

In Iowa and other locations, the turbines keep crops from freezing, extending the growing season. It’s the same idea of the fans in citrus groves in the south.
Here’s an article on this question:

Reply to  Reality check
August 12, 2016 11:09 pm

Most unseasonal crop losses come during clear nights with no wind, from frost.
Frost cannot form if the wind is blowing over a few mph. Unlikely wind turbines will stir the air much when there is no wind to begin with.

Reply to  Reality check
August 12, 2016 11:10 pm

If it could, farmers would have installed windmills and not expensive to run fans.

Reply to  Reality check
August 13, 2016 3:29 pm

“Another potential beneficial impact: Because turbines mix up the air and slow wind speeds, they also could also affect the temperature around them, making nights warmer and days cooler.”
My analogy may have not been the best or not clearly understood. Maybe this article will help.

August 12, 2016 6:18 am

Who pays for a damaged Cape Wind? The funders of the Big Dig (the rest of us) want to know.

August 12, 2016 8:21 am

Sounds like a pre-excuse for when the off shore wind farm doesn’t pan out like they thought.

Bob Denby
August 12, 2016 9:01 am

I’m shocked, shocked, to learn that the air not only moves, but moves at velocities and directions beyond predictability. (Between ‘shocks’ I’m enjoying some first-rate commentary, thanks.)

Bruce Cobb
August 12, 2016 9:13 am

They need to act fast. Pretty soon there will be no more Climate Ca$h, and the wind fakeindustry will fold like a cheap suit.

Reply to  Bruce Cobb
August 12, 2016 1:53 pm

How can that be? Our windophiles assure us that wind is the cheapest form of power.

Reply to  MarkW
August 12, 2016 11:14 pm

Yes, wind is free. However the means to capture it and put it to use is very costly.
Oil is free too, as is coal. Getting it out of the ground costs some money though, but not nearly as much per unit energy delivered as wind.
But the biggest difference is probably that the oil and coal do not appear and disappear unpredictably and intermittently.

Pop Piasa
Reply to  Bruce Cobb
August 12, 2016 4:13 pm

For the wind industry to be anything more than a specialty niche in the power market, each of the devices will have to generate enough energy in its lifetime to reproduce itself while also providing reliable grid base load.
I can’t see evidence of that, can anyone show me?

August 12, 2016 4:08 pm

So basically a wind farm would generate 11% of the nameplate rating instead of 10%.

August 12, 2016 6:24 pm

A refresher on the facts of offshore wind power in the US:
1) Total potential for installed power: 900 GW ( Per the U.S. Department of Interior, Mineral Mining Service, MMS, in their January 2009 “Draft Proposed Outer Continental Shelf Oil and Gas Leasing Program 2010 – 2015,” )
The MMS stated:
“The U.S. Department of Energy (DOE) estimates that more than 900,000 megawatts (900 GW), close to the total current installed U.S. electrical capacity, of potential wind energy exists off the coasts of the United States, often near major population centers, where energy costs are high and land-based wind development opportunities are limited. Slightly more than half of the country’s identified offshore wind potential is located off the New England and Mid-Atlantic Coasts, where water depths generally deepen gradually with distance from the shore. Development of offshore wind energy technologies has the potential to provide up to 70,000 MW of domestic generating capacity to the nation’s electric grid by 2025.”
2) Costs for wind turbines offshore are higher than onshore, but will steadily decline as sizes increase and more units are installed.
3) Average wind speed is higher offshore, providing more output per turbine.
4) Improved technology has been developed (or is under development) by US Sandia National Laboratory, to allow offshore turbines to continue operating in gusty or very strong winds instead of cutting out to avoid damage. The new turbine is HAWT with blades downwind of the tower, and importantly, flexible blades that bend in the wind.
5) Energy storage via MIT underwater spheres allows wind power to be sent to shore on demand and in load-following mode. Net energy loss is approximately 20 percent.
6) US wind energy map shows the location and strength of offshore wind –

Reply to  Roger Sowell
August 12, 2016 11:17 pm

MIT underwater spheres?

Steve T
Reply to  Menicholas
August 13, 2016 4:38 am

August 12, 2016 at 11:17 pm
MIT underwater spheres?
Try this:
I particularly liked the bit “That means 1,000 such spheres could supply as much power as a nuclear power plant for several hours,” gushes the press release……….MIT researchers Alexander Slocum and Brian Hodder believe the build-and-deployment cost for the concept would come in at around USD$12m per sphere, which they say equates to $0.06 per kilowatt-hour, a commercially acceptable rate.
That’s US$12 billion for a “few hours” use of a nuclear plant. After that you have to wait until the wind array is functioning again, plus the time needed for the excess power to “recharge” the spheres! Seems somewhat expensive. Not counting the design and building of a means of deployment of said spheres ( the report admits that this is currently non-existent).

Reply to  Menicholas
August 13, 2016 7:31 am

There are plenty of grid-storage alternatives, if one does not care for MIT spheres underwater. Land-based pumped storage hydroelectric, the Okinawa-style ocean-and-land pumped storage hydroelectric, rail gravity storage, and high-capacity batteries all are viable alternatives.
The MIT storage spheres will be the economic choice as their installed costs fall over time.

Reply to  Roger Sowell
August 13, 2016 7:24 pm

You believe all that cr&p, do you?
What’s Santa bringing you for Christmas this year, Roger?

Tom Halla
Reply to  catweazle666
August 13, 2016 7:29 pm

Mr Sowell’s problem is that he likes to cite really limited technology, like pumped storage, as if it were a practical solution to the intermittency of wind and solar, and come up with bogus objections to what could work, like nuclear.

Reply to  catweazle666
August 13, 2016 8:08 pm

One need only look at the grid stability in California’s ISO (CAISO, or Independent System Operator) and the abundance of wind power and solar power on the grid here. Solar at grid-scale routinely produces 8,000 MW of power during daytime peaks, with another 2,000 to 3,000 MW from solar rooftop systems. Also, wind power provides up to 4,200 MW and varies as the wind usually does. California manages just fine with some of the grid-storage systems described above: pumped storage hydroelectric, and batteries. It also helps to have load-following gas-fired power plants, essentially zero coal-power, and very little nuclear power.
The state law in California requires 50 percent of all electricity sold be produced from renewable energy sources by the year 2050. With very limited wind resources in California, solar power is the only resource that can meet that requirement. Grid stability requires that excess solar power be stored for up to 8 hours. Installed grid-scale solar power capacity will exceed 50,000 MW by 2030, and battery storage will reach at least 30,000 MW with duration of 7 to 8 hours.
What is also true is that the aging US nuclear plants, 99 of them at present, will all close within 10 to 15 years due to old age and unsafe or uneconomic operation. However, the many large pumped storage hydroelectric plants will continue operation, consuming wind power when it is in excess of grid need, and returning 80 percent of that stored power in peak demand.
The coal exhaustion problem is real, and imminent in the US. Denying that fact does not change the fact. Unless, that is, one knows where more coal deposits lie, that can be mined profitably at present prices. Such mines have escaped the notice of the experts at the USGS.
The national grid that relied on coal-power for more than 50 percent of all electricity must adapt to new forms of power, which will be primarily wind power, gas-fired backup, and grid-scale storage as the storage systems mature and price declines.
Or, one could laugh all this off as madness, and miss out on serious investing opportunities.

August 14, 2016 5:32 am

What are you talking about regarding battery storage? Where? What type? My solar system would not have allowed by to tie to the grid had we installed batteries as I wished.
The last I read, Governor Moonbeam was demanding grid scale storage, but so far nothing is on the close horizon. Has there been a break through?

Reply to  McComberBoy
August 14, 2016 8:15 am

for McComberBoy,
Yes, there has been a major breakthrough both in batteries and on the legal side..
The DOE website below has a searchable database of grid-scale storage world-wide. One can filter the results to California, which shows 182 battery systems (“electro-chemical devices”) operating, under construction, or announced.
The most recent large order is for 100 MW and 4 hours operation of lithium-ion battery to be installed in West Los Angeles by Southern California Edison.
As to a technology breakthrough, Nobel-prize winning physicist Dr. Alan Heeger of University of California at Santa Barbara has developed and filed for patents on a greatly improved battery that uses halogenated polyacetylene, HPA. His company is on the web at I wrote an article on my blog, and Anthony cross-posted it here on WUWT a few weeks ago.
The HPA battery has many improvements over the state of the art Li-ion, including one-fourth the cost, twice the energy storage for the same weight, and essentially zero loss of capacity after thousands of charge/discharge cycles.
The status of installing home battery storage systems is the CPUC is still ironing out quite a few wrinkles. There should be more clarity and some decisions made by the end of 2016, as described in this document (apologies for all the legalese):
DRP Scoping Memo filed January 27, 2016 (Distribution Resources Plan)
The predicted outcome is that home battery storage for rooftop solar systems will be allowed soon, with certain conditions to ensure grid stability, safety, and affordability.

August 14, 2016 6:26 pm

” aging US nuclear plants, 99 of them at present”
Since nuclear is an important part of the US power supply, aging is an important topic that is being addressed by the nuclear industry. We have already figured out how to make them last 60 years and are working on 80 years.
Of course wind turbines and solar panels are also aging. I do not think storage will be needed because of the failure rate with time.
“The coal exhaustion problem is real, and imminent in the US. ”
Yes and no. Running out of fossil fuels is not imminent when considering the life span of human or wind turbines. A good argument to wait to build wind farms until they are needed.

Stephen Obeda
August 14, 2016 7:46 pm

“No measurements exist of wind and turbulence around an offshore wind turbine’s rotor blades in the ocean in the U.S., because until now, none have existed.”
— How embarrassing. Maybe Mrs Jennings 4th grade science class can offer them all some suggestions for improving things.

August 16, 2016 7:39 pm

I’m mostly curious about how nor’easters and icing will impact Deepwater Wind than I am about wind flow. However, a query from an Email list I’m on inspired me to hunt down the paper an take a closer look. The paper is available at Not firewalled!
The paper uses data from low level airplane flights and the Cape Wind Met (Meteorological) tower, which was not as tall as the planned turbines. The paper refers to instruments at 20, 41, and 60 meters above MLLW (Mean Lower Low Water, a term I haven’t encountered before), the Deepwater wind turbines are said to be 270 feet (82m or so) tall, but that has to be the tower height, and even that’s too low. says “Hub height 100 m (or site-specific)” and “Rotor diameter 150.95m”. That means the blade tips will be shuttling between 25m and 175m, way in excess of the Cape Wind Met tower. BTW, these are 6 MW turbines with blade lengths 50% longer than any land based turbine I’m familiar with.
I imagine the Cape Wind folks figured their Met tower would cover the boundary zone over the rotor’s swept area and that air flow would be steady above the boundary zone.
The paper says that the air flow is more complex than that. The paper looks at data recorded from an airplane at flight levels 30 – 90 meters, so those are below the nacelle too!
All in all, I really don’t know what the implications are from this. A steady, stable air flow will have wind sheer, with significantly lower wind speed at the bottom of the rotor than at the top. An unstable air flow has much less sheer, but will have quite a bit of random motion, left, right, forward, backward and even up and down. Either way they’ll have some interesting forces, they may have more trouble dealing with the random, turbulent wind.

%d bloggers like this:
Verified by MonsterInsights