Wind Turbines Leave Clouds and Energy Inefficiency in Their Wake

Well this is a portability and averaging problem. You want the turbines to have a low enough density and oriented so the majority of time they do not interfere with each other in a meaningful way. But no matter how good your data is and how skillfully you place them there will be times when they bock each other if you have more than one in an area. So you loose a little power in the worst case scenarios, this is hardly a killer issue just something to be aware of when your planning out you wind farm.

Would it be impossibly difficult to make the wind turbines mobile? That way they could adjust themselves to the current wind pattern.

So I think what this article is saying, is that the rednecks of NASCAR are smarter than the scientists.

Ask anyone that is only a fan and not a part of the racing crew, or ask a fighter pilot. It has long been known that the lead dog has the best air. Why is the turbine industry so far behind in realizing this.

I don't know that it would work for wind turbines, but the engineers could try the reversing rotor stator method that is used to smooth the air flow in jet engines... although I am not sure how they would work this out with machines that large.

Maybe a trailing windsock to confine the turbulent air would be a beginning. That would also help the turbines adjust to wind direction.

Note: I am not a scientist and would have no idea on how to crunch the numbers to see if any of these ideas work. Nore do I have the money to even create a working model. I leave that to you. This is just my brain storm on the reported dilemma.

A comment I pass along from a friend "in-the-know":

Remarkable photo; best I’ve ever seen…if not “retouched” . Only condensation would explain this wake effect and conditions this favorable on water equal fog. Normal 17 RPM rotation is too slow to shear passing wind enough to trigger condensation, even at fastest moving blade tips.

Photo credibility aside, downstream energy depletion effects are real but mitigated by blade-induced turbulence. The standard solution to depletion includes lee spacing of turbine rows at least 10 rotor diameters apart and offsetting sequential rows by ½ lateral turbine spacing distance. Perfect alignment of wind and turbine rows, as in this photo, occurs ONLY when winds are oriented within 5 or so degrees and in stable, laminar flow over perfectly flat surfaces such as ocean surface or West Texas Plains. Otherwise, turbulence, ground friction and general mixing maintain relatively constant “push” expressed in watts per square meter of swept rotor area.

In short, I suspect that someone has stroked this picture to make a point.

JG

I race sail boats and in sailing it is known that wind is affected for a distance of 12 times the height of the sails of a boat. Someone should have talked to sail boat racers before deciding where to place the turbines.

Basically, you should place them offsetting and keep the distance between the offsetting turbines minimal. You can offset them because most places have a prevailing wind from one direction and the exact opposite direction is a large part of the remainder of the wind. Wind normally will only come from other directions during storms and you cannot use the wind during storms because it will damage the turbine. Then the next set should be at a distance of 12 times the height of the turbines from the first set.

I would think that you would have tested these in a wind tunnel and have found that out. The power company should take the time to get professionals and stop trying to hard cut cost.

Instead of this...

x x x
x x x
x x x

How about this...

x x x x x x x x x

Just a thought, as there a whole lot of area to work with on the ocean.

Hay! Looking good; em boys are moving on. It looks like they need to put rotating heads on those kids.

It is impossible to predict the wind direction at all times and the only way to improve this problem is to have a moveable array.

There are several fundamental issues that never get adequate coverage by "sustainable energy" advocates.

1. Wind is not human-controllable. Nuclear energy is.

2. Land is not a replenishable resource. Scaling up wind farm size indefinitely doesn't work.

3. Production per sq. km. for various power sources is not mentioned.

4. Neither turbine nor battery technology is going to undergo any great improvements insofar as large-scale power production or storage.

5. Legacy energy grids are not designed to handle multiple fluctuating energy connections or battery inputs.

6. Countries that currently use a fair amount of sustainable energy sources are small, or use the source(s) in a very limited way. They are essentially toy projects, not models for large applications.

7. The nature and total costs of raw materials, manufacturing, shipping, transport, installation, grid adaptation, spares, maintenance, operation and disposal - in dollars and on the environment - are glossed over in "sustainable" arguments. Batteries especially tend to be nasty tech, as does solar. And windmills manufactured in China???

8. Energy demand currently varies at the will of the user. Suggesting that usage vary at the will of the supply (linked treatise) in order to compensate for the unpredictability of winds is a massive social change.

9. Re 8: The alternative is to overbuild massively so that the probability of insufficient wind power is reduced to some politically correct small number, or supplement with conventional power sources scaled for bad/worst-case wind conditions. Neither is desirable or cost effective, and there is no viable Plan C, except see 8 again.

These are just off the top of my head. There are a lot of vested interests operating in this domain much as there are in "climate science". Beware.

01/22/10 at 8:02 pm

Would it be impossibly difficult to make the wind turbines mobile? That way they could adjust themselves to the current wind pattern.

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Right. And make an already financially untenable energy source into an even bigger boondoggle. Brilliant!

The new wave-power designs are better than wind turbines.Water is much denser than air.Besides,wave-power is available 24/7..

It's so good to see this information and discussion, wind, solar, wave, no long term waste storage, no resource wars, right on!

So many of you discussed your love for vintage clothing in the comments section of my previous posts, which made me smile from ear to ear because I love history. I think it’s important to understand how fashion has evolved and why it has changed over the years. So I am going to go through the decades starting with the 1920s through 1990 and talk about what was popular in the world of fashion. We’re trying something new this week.

I think it´s something good in this fog clouds, as you can see, those fog is reflecting solar rays!. This could be benefical to the eviroment!

xlndr:
The engineers dictating wind tower placement are very well aware that the "lead dog gets the best air".

brfrasier:
This is not a folly of the "power comany" "trying to hard cut cost". They DO have professionals working on the optimum configurations for wind towers. Wind tunnel testing has shown that 10x the diameter is generally optimal. A rotor is not a sail.

Look at the farm from any other angle than the oncoming wind in this one instance and you'll see that they ARE offset. This wind farm was designed for the normal prevailing winds. When this picture was taken, the winds were coming from the rare angle that is known ahead of time to be the least ideal.
Just because everybody loves an underdog doesn't mean that the people on top are idiots.

One way to help with wind turbines is to make the whole wind farm rotate and place the turbines on a slope structure.

Whys33301/23/10 at 2:36 am
Instead of this...

x x x
x x x
x x x

How about this...

x x x x x x x x x

Just a thought, as there a whole lot of area to work with on the ocean.
******************************
What if the wind shifted, and began blowing left to right?

Even if every other turbine were shifted to the side, such that

X X X
X X X
X X X

became

X .. X .. X
.. X .. X .. X
X .. X .. X

A diagonal wind would line them up again.

Possibly a device looking like a venitian blind between them would reduce the turbulence. But then it would slow the wind.

Possibly if every other one were a lot taller, it could stay out of the cloud's path.

(I had to use dots to keep the program from jamming the X's together.)

The best place for a wind turbine is at the top of a hill.
1. Foundations are cheaper (1/3 the cost)
2. Wind speed amplifies as it charges up a hill (topographic factor)

I don't know why they keep insisting on putting wind farms out in the ocean. If I had to spend money on a turbine, I'd at least put it in the best spot available.

The answer to this problem is so simple that I'm surprised no one has suggested it. Placing the windmills in a random pattern would limit the problem. The pattern would not have to be truly "random", just apparently random. I can visualize Mills along arcs of non-equal diameter circles. You might loose space for a few Mills but almost never would more than a pair of Mills would block another.

Not

X X X
----------------------------

Yes

X.X.X
.....
.....
.....
..... ~~
..... ~~~~
..... ~~~~~~
..... //
..... //
-----------------------------------------

As long as the turbines are placed within a certain distance of e/o there willl always be interference among them under certain wind conditions. Any obstacles in a wind gusts path effects its trajectory both vertically and horizontally, the ocean is simply the place with the least obstacles and therefore the best efficiency predictability for turbines. I do find it intriguing that the max efficiency for these things tops out at 60%, and many designs do not even come close to that. I agree that wave power generators are probably a better option in the long run, but then again both of these techs are still young. I hope to see some renewable power hubs someday that combine multiple renewables working together.

If you must have wind farms with horizontal axis machines in rows, one way of recouping some of the energy in the vortices of the lead row would be to alternate the direction of rotation of the rows so that the apparent wind at the next row is increased. This would of course double the manufacturing commitment for blades. Because the airstream would be a bit variable, the blades would need to handle more turbulence, but there is no free lunch. A recent development from Edinburgh where the gearbox is replaced by a variable displacement hydraulic pump looks a promising way to go.