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New Generator Boosts Wind Turbine Efficiency 50%
MagnetDroid writes "A startup company based in Vancouver has developed a new kind of generator that could harvest much more energy from the wind. The design could not only lower the cost of wind turbines but increase their power output by 50 percent to as much as 100 percent, in some locations. Normally, when wind speeds drop, a turbine's engine becomes less efficient. The new engine, from ExRo Technologies, runs efficiently over a wider range of conditions. The design replaces a mechanical transmission with what amounts to an electronic one. Magnets attached to a rotating shaft create a current, but individual coils can be turned on and off electronically at different wind speeds." The company will begin field-testing a small, 5KW wind turbine by early next year.
Wind energy is a lot like politics and advertising. The more it blows, the more spin you see.
-=Bang Bang=-
Since when is an increase of efficiency by 100% impossible?
For arguments sake, let's say that current wind turbines are 10% efficient. This new turbine is therefore 15% to 20% efficient.
But will this make home wind turbines effective purchases? I doubt it.
I hope the design can be retrofitted into existing turbines, since there are so many deployed now.
No.
The generator is more efficient in changing wind conditions. When the wind is faster, it turns on more coils to provide greater mechanical resistance and takes more energy out of the wind. When the wind is slower, the turbine can still run because the generator can be switched to take less energy out of the wind.
This isn't a consideration for regular power plants because the amount of energy sent to the turbine is well-controlled and doesn't vary with time like wind speed does.
I claim first use of "Error No. 0B" - or "No. 0B error." It'll be the new ID 10T!
"The design could not only lower the cost of wind turbines but increase their power output by 50 percent to as much as 100 percent, in some locations."
100%? Why stop there?!
Because, due to this having not a damn fucking thing to do with perpetual motion or snide remarks regarding such, there's only so much energy that can be extracted from the wind. Getting a 1.5x to 2x boost -- over the course of a year, meaning combining periods where the windmill was operating efficiently, and those times where it was not -- is great. I don't know why you phrased your question the way you did.
Oh, and, uh.. why is this whole article about windmills? Couldn't these improvements in generator efficiency be used across the board?
Not really. The majority of turbine generators are designed to operate at a single, optimal frequency. Wind however is by its nature variable, so to get peak efficiency across various RPMs requires some extra ingenuity. Maybe this could be applied to your car's alternator, I don't know.
The enemies of Democracy are
About a month ago, I was travelling on I-68/I-70 in Maryland, over the Cumberland Gap, when I saw a several wind turbines in the distance. After I got over the neat factor (even though we have them here in WV), I quickly realized that with each revolution of those turbines, we could/would be cleaning up the environment that much more. That alone makes me back this program 100%. Will it reduce foreign dependency as well? Let's hope so.
But, we are all going to have to get over seeing them as ugly or migratory-bird killers for this program to work. I truly want a future where we use very little foreign energy, and we harness renewable energy sources. I say we get those new turbines into the wild as quickly as possible. T. Boone Pickens, get to work!
So let me get this straight -- it's more efficient, has fewer moving parts, has a higher power output, and is cheaper to mass produce? Buy that engineer a beer! This is a real leap forward in a machine class that hasn't made more than incremental improvements for awhile now. The spirit of Nikoli Tesla approves. Next question: Can this technology be adapted for use in the hydroelectric industry? I think it may be possible, and it would reduce maintenance costs somewhat -- maybe we could throw out the sluce gates and make water flow through the dam with fewer electromechanical parts?
#fuckbeta #iamslashdot #dicemustdie
TFA doesn't mention specific percentage improvements in efficiency. That was kdawson's contribution, and then only in the poorly-worded headline. TFA is claiming that the overall output of a given wind turbine could be boosted by 50% or more by altering the dynamics of the generator to make it more efficient over a wider range of wind speeds.
Basically, turbines are most efficient at a given speed, and efficiency drops off for anything outside of that, whether faster or slower. This new design attempts to address that by decreasing the amount by which the efficiency drops off at different speeds. The improvement in the efficiency curve boosts overall power output, as the turbine isn't as strictly limited to a given wind speed for peak efficiency as it was before.
You can never go home again... but I guess you can shop there.
100% increase means that it doubles the original amount of power output. That's not impossible. Even tripling (200% increase) may be possible in time.
...how something like a CVT would work for a wind turbine.
bork bork bork!
Ever read summaries? Most power generation is able to work with reasonably constant RPM's. Windmills don't have that luxury, so often are working at RPM's that are not optimum. This method (if it works) widens the optimum range.
The world is made by those who show up for the job.
power output != efficiency
FAIL
http://greenobyl.com/ please.... think of the children!!
That's 100% of the maximum possible output of the generator. Not 100% of the energy that comes into it being converted into electricity.
The words, they MEAN things.
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It's a transmission for wind turbines..so no? And increasing power output by 100% means doubling the power output. I don't see where perpetual motion comes into it.
A 100% improvement in something just means it has been improved by a factor equal to what it can already do. In other words, it's twice as efficient. If you can't understand that then you might want to think twice before posting on /. /just sayin'
CAn'T CompreHend SARcaSm?
If 1 wind turbine can output 1MW. Increasing that to 2MW would be 100% more output. It can still only be 10% efficient, but the output has doubled. 50% more efficient would be 1.5MW. Heck it could be possible to get up to 1000% more efficient (10MW), and still be at under 50% efficiency.
Maths, don't leave home with out it.
Read somewhere that hydraulic-pumps up in the air on the turbine with hoses all leading to a central electric generation plant nearby brings down the maintenance cost considerably. Efficient generators are more expensive and require more skilled maintenance than hydraulic-pumps factoring in the loss of efficiency with the hydro delivery system.
100%? Why stop there?!
Doubling of efficiency is not impossible!
What they are doing is known as "regenerative braking" in the automotive industry. It's hardly new. It's established technology. Likely this is the first application to wind turbines.
Wind turbines typically have mechanical transmissions and/or braking systems to maintain their peak efficiency. The problem is, mechanical transmissions have friction and equate to lower efficiencies due to frictional losses. Furthermore, this means it's likely the gearing of a mechanical mechanism is less likely to actually achieve ideal efficiency for a given generator. If you've ever driven a stick, then you likely understand.
Moving to an electronic system means you instantly get a boost by doing away with frictional losses. Next, you gain another boost from actually running your generator at peak efficiency all the time, and in much lower and/or higher winds than previously capable.
Frankly, I'm not only surprised this hasn't been applied sooner, I'll be very surprised if this is vapour-ware.
Lets say you run your generator for 24 hours per week. That is its normal power output. Now, run it for 2 days. You have just doubled its weekly power output. That's a 100% increase.
Run it for 3 days. 200%
That doesn't violate any laws of physics. This design simply makes the generator capable of being operated at times that it normally would not be able to operate at w/o excessive loss.
You are confusing efficiency with power output.
Out of modpoints but really liked a post? 1BDkF6TtmmeZ3yqXbz9yhdYVqRYnwFoXDj
"It is better to keep your mouth closed and let people think you are a fool than to open it and remove all doubt."
Just like most of the energy contained in a gallon of gasoline is not converted into forward motion, most of the energy passing by a wind turbine is not converted into electricity. It's the "low hanging fruit" in energy research. It sounds like their idea is to use more but smaller and more efficient generators that are adapted to input from variable wind speeds rather than constant input from another source, like hydroelectric dams or steam powered turbines from nuclear plants. It also says they are electronically controlled, which may eliminate the need for wasteful transfers of energy, like varying the blade pitch, mechanical clutches, etc.
Still not as effective as conservation, but unfortunately, conservation can't have an IPO, and doesn't get a lot of business press.
According to the company's website, which does have pictures of the design for anyone who is interested, this could be used with other energy sources than wind:
While this overview focuses primarily on the wind applications, VIEG Technology is expected to have a material impact on the economic viability of a wide range of renewable energy applications.
There you go. I predict this could be more applicable in tidal energy than traditional big-dam hydro, although it might be useful in small, run-of-the-river projects to make them more efficient. They might even be useful in big run-of-the-river projects, which will create over 1,000 megawatts of new electricity in the next few years in British Columbia alone.
if (answer.indexOf("Definition of efficiency") 0)
exit("FAIL!");
The first thing I wondered was "what makes this design different?"
This is a nice, simple explanation of why this design can be kept efficient in a wider range of wind speeds.
Since we love to bash some of the lamer summaries, I think this one deserves a bump on the plus side.
Most power generation is able to work with reasonably constant RPM's
How about brakes in an electric vehicle?
(BTW, that apostrophe is superflous)
Free Martian Whores!
Whoever added the tag has no clue. This IS a generator.
Right, because pictures are proof. Just like the phantom console, which had pictures (http://gamedeveloper.digitalmedianet.com/articles/viewarticle.jsp?id=19801) and is totally real right now. In fact, I'm playing the invisible version as I'm typing this!
The car alternator is a great idea, but it would work in reverse. At higher engine speeds it could get by with less active coils reducing both its electrical output and mechanical resistance. Since the charging system usually only needs a fraction of the potential output. For you bass/spl junkies it could sense demand and crank up a few more coils. Damn now my wife will be fussy with me for a few weeks while I build one for my TDI...
He has a point, even if 'pics' won't make much difference the vapourware will stick. There is this thing called Betz' law and it is pretty specific about how much energy you can extract from any moving medium.
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(the word is "superfluous.")
Handled by a CVT, and they have to apply normal brakes for the last few mph anyway. Plus, regenerative braking is limited by how much charge the batteries can handle taking, not the output of the motor-generator.
Not a typewriter
somebody is telling a stretcher here. Power goes as the cube of the wind speed. There's no point in trying to squeeze a few more percent at the low end of the range. There's just no power down there to squeeze out.
for example, at 1/2 top speed, you're getting 1/8 or 12.5% of full power at best. If it's actually 8% due to slow generator speed, no big deal. Another 4% is not worth spending much on.
That's called maximum power point tracking and is pretty old in concept and in actual use today in many thousands of wind and / or solar installations.
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I'm a Canadian, and proud to be one.
That notwithstanding, where is Vancouver? This is where the company in question is from. There are 3 Vancouvers on the west coast, two at the "bottom" (south edge) of a boundary (BC, WA). Vancouver Oregon is mid-state at Portland.
Well, this proud company won't give its snail mail contact, just email and area code. I guess they are trying to fool the masses that they are from the USA, because they are from the Canadian Vancouver. Not really surprising, as Vancouver Canada is much bigger than the other Vancouvers. The area code verifies it is Canada.
What is the problem here? Are Canadians stupid? We are incapable of doing anything that the world will find useful? Canadians were involved with the original Apollo program, but I doubt this is public knowledge in much of the USA. Is the business so marginal, that to let it be known that it is Canadian, is going to see it fail? Is it doing something which doesn't allow IP laws (as much as they are bogus these days) protect it in some way?
Yep, but since the most efficient turbines are already at more than half Betz' limit this is simply not going to work.
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Actually, if they used more ideas from your car's alternator, they might get farther yet. But that's just my humble opinion.
According to TFA, this new generator uses permanent magnets on a shaft passing by coils of wire, so the magnets are always spinning, even in the slightest breeze. This isn't anything new, it's just that they're probably using IGBTs to turn the individual stator coils on or off, changing the load on the shaft.
An automotive alternator uses an electromagnet on a shaft (rotor) passing by coils of wire(stator). The amount of voltage fed to the rotor comes as a form of feedback from the regulator, which samples the battery's voltage and the alternator's output and adjusts the rotor voltage as needed. This design assumes more or less unlimited rotating force to the rotor from the engine, and that's not necessarily the case with wind generators.
I'm going to guess that the other thing that's happening here is that when this new generator is in "weak" mode, the DC power output will appear pulsed, like a square wave, so I'm sure there's going to be some more regulation electronics on the back end to get it to spit out straight DC.
I've used hydraulics. The efficiency is rather poor (remember in a wind turbine the hoses have to rotate or you need a rotating pressure joint - the thing has to face the wind, and to get good output the prop center needs to be high up meaning long hose runs.) I find it very hard indeed to believe that a PM generator with adaptive electronic control needs more maintenance than hydraulic systems, or that any cost savings outweigh the loss of efficiency over a 20 year plus lifespan. As a simple example, rail locomotives are Diesel-electric rather than Diesel-hydraulic. Hydraulics are (to the best of my knowledge) mainly useful when you want to get variable speed drives off constant speed prime movers, such as when you want the same prime mover to act as an AC generator on fixed 60 or 50Hz while also using it to power thrusters.
From scarped cliff or quarried stone she cries "A thousand types are gone, I care for nothing, no not one."
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So what of the things that rarely fails me is a "common sense" check on new designs, particularly when it comes to renewable energy concepts (as there are a lot of impossible inventions around).
So let's break down this design:
- Works like a normal electric motor so thus we know it works *CHECK*
- Have electronic switches to open and close a circuit, which we know works *CHECK*
- We know longer circuits have more resistance than shorter ones *CHECK*
- We know changing the number of coils in an electric generator is optimal for different levels of generation *CHECK*
So it seems to be a very good design that should work very well. Their claims of 100% more efficiency are a little over the top but may work in some locations. I think it is safe to say that most locations should see an increase in efficiency with the new design over the old one.
The way they've built their motor is also a little novel but only really amounts to a way to customize the motor for different situations and thus really isn't all too interesting in the grand scheme of things.
had to it, hadn't been done yet......
OK, a little off topic here, but question for anyone who can actually answer knowledgeably:
If the wind is turning these turbines, it's obviously taking some energy out of the wind. If wind farms become massively deployed, couldn't that change weather patterns as we alter wind energies? Or, is the difference so negligible that the amount of turbines constructed for our energy needs would only be a fraction of what is necessary to cause such a disruption?
Not that I'm against wind energy, mind you. However, with all this talk about using wind energy because it's a green solution (i.e. to reduce global warming), the thought occurred to me that we might still be messing with localized weather->regional climate->global climate yet again.
CAn'T CompreHend SARcaSm?
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It's kind of like a transmission. It's actually also kind of like the reverse of the adjustable displacement engines in some vehicles.
In some cars, you have an 8-cylinder engine but can use 4, 6, or 8 cylinders at various times based on the amount of power you need to generate. It doesn't take 8 5 liters of displacement to maintain highway speeds, but getting up to them quickly may. Turning off cylinders not in use saves fuel by not burning it when it's not needed. Each cylinder only draws chemical energy to make kinetic energy as needed.
If you left all the coils engaged, you might have too much resistance to generate any electricity in light winds and too much to generate it efficiently in more moderate winds. Yet if you build a turbine specifically for only light or moderate winds, you don't get any additional power once it is maxed out.
This solution uses wind, but you can't just press down on a pedal and ask for more wind (well, you could ask, but you'd be disappointed most of the time). So what it does instead is it has a magnet-in-coil generator with separately activated coils. Each coil only draws mechanical energy to make electricity as the mechanical energy is available. The rest of the coils are left as open circuits. If there's enough wind to turn the blades with half the coils on but not all of them (or too slowly to make sense with all of them), then you just open the circuits on half the coils and the other half keep generating. Only the coils in a closed circuit generate current and present meaningful resistance to the turbine. As you have more wind, you generate more power up to the maximum. The maximum number of coils doesn't impede this turbine from generating less current when some wind is still available though, because it just disconnects the spare coils until they are needed.
It is real.
It never went to market.
The keyboard did, and is a pretty good keyboard from what I hear.
You're confusing Power with Work.
Never having gone to market still means it didn't exist. Concept devices and mockups don't count for most people.
But at least you've got a cool keyboard.
Those things you're doing with that stuff you just bought? That's not what it's for! -
Just out of curiousity, and I haven't RTFA yet so maybe the answer is there, but couldn't you vary the pitch of the vanes on the turbine to maintain a constant RPM in varying wind conditions, much the way a constant speed propeller on an airplane works?
There would still be a range of wind speeds for which this would work, i.e., too little wind and the propeller will stall before reaching the optimal RPM as you keep increasing the blade pitch, but it seems like it would work better across a wider variety of wind speeds without requiring the complexity of this new generator.
MCSE? No, sir...I don't do Windows. Yes, I am an idealist. What's your point?
It seems like just a matter of semantics, but for the record an engine is not necessarily an internal combustion device.
A motor is a subclass of engine. Really an electrical generator is a motor in reverse, so again...who cares?
Also, the article uses the term generator anyway...uhm...am I feeding a troll!?!? ^&#$!!!
-t.
How about a car's alternator with constantly changing RPM?
am i the only one worried that with a boom in windfarms, the drag on the earth's rotation will increase, slowing it and lengthening the day, making me stay at work *that* much longer?
Wind however is by its nature variable, so to get peak efficiency across various RPMs requires some extra ingenuity. Maybe this could be applied to your car's alternator, I don't know.
Car's alternator uses only fraction of available power. Bad wind generators use all of available power, reducing the turbine RPM to 0 when wind speed is low. Then wind turbine has to start spinning again, which might be difficult, because it has to turn shaft that just stopped on big strong magnet pole. Sometimes wind speed is not just high enough to start spinning, so it does not starts to turn and energy is wasted.
The advantage of this design is that lots of small coils stacked slightly rotated makes a lots of smaller resistance peaks instead of several stronger resistance peaks. This allows the wind turbine to start to move easier than it would with a average generator. Design with lots of coils makes higher voltage at low RPM, making the generator more useful with low speed of wind.
Stacked up and slightly rotated coils and magnets look like great solution, but the electronic that switches coils on and off is the bonus to the efficiency at low wind speed.
--
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Windmills don't have that luxury, so often are working at RPM's that are not optimum. This method (if it works) widens the optimum range.
Close but not quite what they're getting at. What they're doing is increasing/decreasing the resistance to keep the windmill in the optimum RPM range over a larger range of wind speeds. So at 5 mph, the blades might spin at 20 rpm and generate 2 MW. At 15 mph, with the new system the blades still spin at 20 rpm, but now generate 5 MW. As oposed to traditional generators, where it would be spinning at 30 rpm and only generating 3 MW.
Just out of curiousity, and I haven't RTFA yet so maybe the answer is there, but couldn't you vary the pitch of the vanes on the turbine to maintain a constant RPM in varying wind conditions, much the way a constant speed propeller on an airplane works?
They do that too, even on existing windmills. The problem is that when the wind speed is low, there's nothing you can do to make it go fast, so if you wanted to maintain constant RPM in the generator, you'd have to pitch the blades to give very low speed in high winds, which is rather counter-productive. Adjusting the resistance of the generator so it works across a wider band of RPMs, combined with adjusting blade pitch, provides much better results.
The enemies of Democracy are
Yes, the keyboard was real, but of course that was not what the phantom console was supposed to be and was not what the pictures were of. That the company managed to take all that startup money and produce a keyboard with a stand is... well better than nothing I suppose, but the phantom console remains firmly in the land of vaporware. Or maybe just plain fraud.
I hope the design can be retrofitted into existing turbines, since there are so many deployed now.
According to the article, it should be possible:
The next step will be to install larger, megawatt-scale generators in existing wind turbines.
Only speak when it improves the silence.
Regardless of the rpm, the car's engine is always producing enough power to turn the alternator against its resistance. The same is not true for standard wind generators; if the wind speed drops, there is no longer enough power to overcome the resistance of the generator. It sounds like this new design can reduce the resistance, therefore generating a reduced amount of power under conditions which would cause a standard design to generate no power.
Wind turbines do not work that way.
No kidding!!! What do you say at this point?
You're confusing power with Power. One is in units of watt-hours, and the other is in terms of watts.
The Cumberland Gap isn't crossed by I-68/I-70 in Maryland. It's near the junction of Kentucky, Virginia, and Tennessee.
Get real; you won't see home wind turbines, at least not en masse. They have too much vibration and transmitted noise to hook up to your house plus I'm sure the neighbors might object to the aesthetics. Maybe if I had an acre or two....
power output = power input * efficiency or power output / power input = efficiency and since power input of a windmill is outside of your control, it could be considered constant, so any changes to efficiency translates to changes in power output. Hence you FAIL
Drat!
Free Martian Whores!
If you're going to critique one's use of the apostrophe don't fuck up the use of the period, your spelling or your understanding of this particular acronym.
Technically you don't need the 's' either, as RPM stands for 'Revolutions Per Minute.' Adding the 's' or the apostrophe makes it 'Revolutions Per Minutes.' In that case you'd want to make sure you have clearly stated the amount of minutes you're talking about so your 'RPMs' doesn't completely lack meaning.
You can't even spell 'superfluous' for FSM's sake.
Isn't it nice for someone to be a bitch about your English?
In this house, we obey the laws of thermodynamics!
The only way to tell the difference between a hamster and a gerbil is that the hamster has more white meat.
Were you aware that the voltage regulator used in automotive applications works by varying the current to the field coils of the alternator? Apparently, not.
On the east coast of the USA, most of the rivers are fairly steady. But were in the west, we have LOADS of reservoirs and streams. These have varying amounts of water coming from them all the time depending on seasons and all. This generator would allow a DIRECT connect and to bypass using a transmission. It really could open the door for a number of new hydroelectric operations IFF it is inexpensive.
I prefer the "u" in honour as it seems to be missing these days.
That's one of the things about these new windmill generators, they do it without transmissions.
Free Martian Whores!
the windmill will be able to function in a wider range of wind conditions meaning that the power input will change. Hence you FAIL
http://greenobyl.com/ please.... think of the children!!
I'm not sure if you're being sarcastic or not. There was recently an article in the local Portland, OR news about how the windfarms that have been installed in the Columbia River Basin may actually have a detrimental impact on salmon. Apparently, some parts of the electrical grid in this part of the country are operating near peak capacity. When the wind really kicks in and pushes the grid to its limits, other parts have to lower production. In our case, this means letting a lot more water spill over the dams. This, in turn, tends to introduce way too much nitrogen into the water, which harms the fishies. Or so goes the theory.
Ah crud! You're right. I missed that skimming just the first part. Looks like they just electronically switch different or more generators in and out of they stack as needed. But if I read it correctly, it's able to both adjust resistance and switch in different parts of the stack for different wind speeds and rpm's. 2 "new" variables to adjust efficiency.
The world is made by those who show up for the job.
Maybe not your car's generator but definitely being used by bikers on their bicycle generators for powering LED lights.
http://candlepowerforums.com/vb/showthread.php?t=172636
The car's alternator already uses something sort of like this to regulate voltage, it doesn't bother to extract more power at higher RPM because it doesn't need that.
If they keep on making 100% improvements pretty soon it will be 400% efficient
"...and yet, I blame society" Duke - Repo Man
Since when is an increase of efficiency by 100% impossible?
For arguments sake, let's say that current wind turbines are 10% efficient. This new turbine is therefore 15% to 20% efficient.
Damnit!
I have been reading Slashdot all this time, and I only now realize that an "Insightful" post is one where you answer your own question :P
Actually, no, it doesn't. It varies the voltage to the rotor.
Here's a schematic: http://mightymo.org/Proj_OneWire.html#DELCO%20SI%20schematics
Color me ignernt here, but why would you even need a transmission in the first place? When I first started thinking about wind generators a few months ago, I just assumed the magnets / coils of the generator would be right there on the shaft of the wind rotor. Silly me, I guess. Can anyone here clarify what happens inside most wind turbines?
Cheers,
"What in the name of Fats Waller is that?"
"A four-foot prune."
Whoever added the tag has no clue. This IS a generator.
It generates. So loosely speaking it's a generator.
But there is a terminology distinction when you get into TYPES of things that generate. They all have coils and a field in relative motion to create the output voltage. But a "generator" creates the field with electromagnets (generally using more coils driven by an external electrical source, a side-effect of the current in the output coils, or otherwise by pulling power from the input shaft) as opposed to a "magneto" which uses permanent magnets.
For wind generators this is a significant distinction: The field coils can gobble up a lot of power - and more when the wind is lower, when you have less (or none) to spare. Paying for that up front, by shelling out for somewhat pricey permanent magnets, is (at least for small mills) far better than paying as-you-go by pulling power off the top of your output. With magnetos you get it all. Thus the recent availability of high-strength neodymium magnets has led to a revolution in magneto design.
But with magnetos you have a harder time controlling the "wild AC" from the wind-speed variation: With generators you can adjust the field to regulate them. With magnetos you're stuck with the output voltage you get, driven by the RPM. This is a problem: The power available from the wind with a given rotor size varies with the third power of the wind speed. But (assuming you don't vary the blade pitch or have a variable transmission between the turbine and the magneto) the RPM and voltage go with the first power. That means the available current goes up with the second power of wind speed and the resistive heating in the coils with the FOURTH power.
Burnout is the limit on your output. So there are a number of ways of matching a wind turbine to a load and avoiding self-destruction. Some of them work by throwing away a lot of power in high winds that it would be nice to keep.
Bantam Dominique roosters crow a four-note song. Once you've heard it as "Happy BIRTHday" you can't NOT hear it that way
Wind turbines generate peak power at a certain RPM, so this device uses a transmission to change the effective RPM of shaft to the generator. Why not use a continuously variable hydraulic transmission - those have been available for quite awhile in vehicular applications. Are the losses in efficiency too much, or are they too expensive? It seems like it might be a more proven and resilient technology.
Yeah, but that's not what the summary says. It says it's increasing the efficiency to 100%. Depending on what it's referring to this means that (a) it's extracting all the kinetic energy out of the air, which means air flows into the turbine but not out of it; or (b) it's extracting all the kinetic energy out of the drive shaft, which means the drive shaft stops. Either of these gives you hilarious results and division by zero errors.
TFA is much clearer, saying that the new generator can give up to 50% more power over the existing generators, which are 90% efficient in optimal conditions but much less efficient at other times. In other words, the 50% isn't applied to to the 90%. It is, I'm afraid a simple basic numeracy FAIL on the part of whoever compiled the summary.
That said, this does like a very neat gadget and will probably be useful in a lot of situations, such as regenerative braking on cars.
Maybe in winds that are too low to start the blades spinning, but breezy enough to keep the blades turning, they could apply electrical power to spool up the blades in order to overcome any startup inertial forces?
(One long sentence seemed easier than actually writing a paragraph.)
Wait... so I didn't read this quote in the first paragraph of TFA?
I'm so confused...
My blog. Good stuff (when I remember to update it). Read it.
I wasn't expecting much, but read the article anyway and I was pleasantly surprised by the stuff they got right. And even more pissed off by the stuff they got wrong.
Yes, switching out windings at low generator speeds will tend to make it more efficient. This applies to PM machines, and could probably apply to induction machines too (though with some other issues).
However, there are many, many other things limiting the power captured from the wind besides the generator efficiency. Blade efficiency tends to drop at low wind speeds, as does the total power available from the wind (it goes with the wind speed CUBED). I'm skeptical that improving the generator efficiency will result in much change in the overall efficiency.
Also, they fail to discuss cost. Very, very few wind turbines today use permanent magnet generators. Why? They're expensive, and you need power electronics rated to the full power of the generator (say, 2 MW) to rectify the output and invert it back to AC. Power electronics of that scale are expensive too. Instead, most wind turbines use induction generators (cheaper) with power electronics controlling only the rotor currents (rated to about 30% of the total turbine nameplate rating). Until they deal with the cost issue, it's really just another trick to get a little more energy out of a PM generator.
And, speaking of energy, the author of that article needs to be locked in a room and made to write "power != energy" on the blackboard a thousand times.
On a large scale it is.
Looking at very large scale projects, you can conclude that there's always wind somewhere, so placing many windturbines around the country will substitute a conventional powerplant.
Of course, it does mean that that you treat a network of turbines as having a much lower output then it's theoretical average, but that's a consession you have to make
|Car anaology| So using magnets and coils is like a really efficient transmission, allowing extracting the maximum amount of energy possible from the wind at low through high wind speeds. Brilliant!
The summary says nothing mathematical about efficiency (other than we can presume it is somewhat higher). It says "increase their power output by ... as much as 100 percent". I take this to mean the new design puts out twice the power of the conventional design under special conditions. Since this is supposedly in the speed band where wind turbines are said to be particularly inefficient, this hardly requires that we violate the laws of thermodynamics.
On the other hand the slashdot title, I suspect, is wrong. Even where a conventional generator would be operating at 0% (not putting out any energy), I have considerable doubt that the new design operates anywhere near 50% efficiency, even though expressed as a percent the power increase is infinite.
Post may contain irony: discontinue use if experiencing mood swings, nausea or elevated blood pressure.
Even taking into account the increases in efficiency this would provide, it still doesn't solve a fundamental problem - if the wind isn't blowing, power won't be generated. Certainly in this part of the country (Ontario), there are periods of time, days long, when the wind will not blow. And the province still needs the same amount of power regardless of the present wind speed. If the power can't be counted on, then backup generator stations will need to be built to generate power when the wind can't. And wind power is far more expensive than other sources of power. At least twice as expensive in most cases, if not a good deal more, from what I understand. So not only is it more expensive when it does work, but even more money will need to be spent to provide backup power when it doesn't. Aesthetics and health also must be taken into account. While some find them beautiful, to many they are an offensive blot on the landscape, particularly in serene, peaceful, or sublime areas. Their noise production is not insignificant for those living nearby. And recent studies show they can have a negative impact on human health when people are located close enough to them. So if wind power is to be used, the installation should be done in such a way that it will not destroy the beauty of the landscape we are trying to preserve, while recognizing that backup power will still need to be built.
If you're getting the same wind power in (by definition you are), and outputting more electrical power, how is that NOT an increase in efficiency?
My blog. Good stuff (when I remember to update it). Read it.
it IS an increase in efficiency but TFS is talking about an increase in power output by 50%-100% NOT in efficiency.
http://greenobyl.com/ please.... think of the children!!
They're that efficient at constant speeds. Too bad the wind isn't constant speed. These generators ARE more efficient over variable speeds, as in, they convert more of the total wind energy the blades harness into electrical energy than other designs. Standard designs can't harness the extra energy when the wind is blowing harder than their top efficiency speed, and they provide to much resistance to be efficient when the wind is blowing more lightly.
My blog. Good stuff (when I remember to update it). Read it.
The same energy is going in. The wind is blowing. If you put out 50% more power, you're both more efficient at converting the wind energy into power AND you're still increasing the power output.
My blog. Good stuff (when I remember to update it). Read it.
With magnetos the voltage goes up with the RPM. In a simple direct drive mill with no pitch adjustment the RPM (for a given efficiency) goes with the wind speed. Operating above the ideal RPM cuts your torque, too far below it also looses you torque by causing the blades to go into aerodynamic stall.
In a battery charging application there is no current, and no load torque, on the blades until the RPM is high enough that the voltage from the genny is above "cutin", the sum of the battery voltage and the diode drop. Above that wind speed the current rises, the torque resistance rises, and the RPM no longer rises as fast as the wind speed. The ratio of RPM to wind speed drops as the wind speed rises further, passing through the efficient ratio and working down toward stall and virtually complete power loss. (If the mill, wiring, and battery guts were all superconductors the mill would freewheel up to the cuting speed and then never go any higher. Due to resistance the RPM still ramps up, though more gradually than wind speed, as voltage working against resistance ramps current.)
A mill with no further way to adjust things can be "tuned" for low cutin - getting some power from low winds but stalling and losing lots of opportunity to generate high power in moderate to high winds. It can be tuned for high cutin and lots of power in storms but nothing in low and normal winds. Usually it's tuned to grab as much as practical in typical winds and lose out in low winds and storms.
A "maximum power point controller" adjusts the load to get the most out of a range of winds. Typically this consists of a "buck converer" on a mill tuned for low cutin, which lets the mill run at the efficient RPM for the wind and trades away the excess voltage for higher current, getting enough extra charging to more than pay for its own losses. It's a hunk of potentially failing electronics.
Switching coils to different current/voltage tradeoffs can do a similar variable tuning with considerably simpler circuitry and less failure risk. (A typical arrangement is delta/Y conversion of a three-phase alternator, which just about doubles the output in high winds - but causes a sudden jump in torque load on the spinning blades and a spike in current and resistive heating when it "downshifts" to delta.)
This looks like they have a LOT of coils to switch around, allowing fine enough adjustment to be more practical than delta/Y without the high-frequency electronic switching and failure modes of a buck converter.
And yes they would want to pick some small amount of power at low wind speeds (it's better than nothing) and add more coils as the wind speed rises. Power goes up with cube of wind speed but RPM, and thus magneto voltage, with the first power. So torque (produced by load currents) goes up with the square. At higher winds it's simpler to add more electromagnets dragging on the rotating permanant magnets than to increase the current in each of them with the square of the voltage rather than the first power of ohm's law.
Bantam Dominique roosters crow a four-note song. Once you've heard it as "Happy BIRTHday" you can't NOT hear it that way
Nobody explored the impact in the past what makes you think people would do so now? (and for those that do, did anybody listen to them?)
Exchange one problem for another future one. That's human politics.
(birds are a non issue; bats are a problem that some research grants can work on solving while we fight like hell to get daft city officials to allow 'unsightly' wind towers.)
Democracy Now! - uncensored, anti-establishment news
yes, but TFS is only talking about the percentage gain in power output not in efficiency.
obviously there is an increase in efficiency, duh. THS just doesn't ee fit to mention how much.
http://greenobyl.com/ please.... think of the children!!
Couldn't they just run the generator through a rectifier and inverter to match the grid waveform?
Why limit yourself mechanically based on the grid's requirements?
1. Generate AC (any waveform, any speed)
2. rectify to DC
3. invert to grid
4. profit!
My other sig is a Porsche!
This is just another maximum power point controller.
Some work by using a switching regulator to change the voltage/current ratio.
Some work by switching coil arrangements on the magneto to "shift gears" for efficient operation in more than one range of wind speeds. (Delat/Y switching is an example of this, giving two "gears".)
This appears to be the second approach with a large number of "gears" in the "transmission".
Bantam Dominique roosters crow a four-note song. Once you've heard it as "Happy BIRTHday" you can't NOT hear it that way
He's the one who brought the "laws of physics" into it, so you'll excuse me for using the definition, and not the marketing.
The French have a tidal hydro station that has been running since the 1950s which might have benefited from something that can handle variable speeds but other than that you will know how fast the water is going to run from early in the design stage.
An engine consumes energy to produce motion.
Generators use motion to produce energy.
Terminology does matter.
Sig Battery depleted. Reverting to safe mode.
Vaporware in the sense that it never made it to market.
It did exist, and functional units were shown.
It was just a PC with set hardware in a console-style box, with some lame software to download new games.
Fraud? Probably.
But it's still real.
Functional demo units don't count?
It certainly existed.
Get real; you won't see home wind turbines, at least not en masse. They have too much vibration and transmitted noise to hook up to your house plus I'm sure the neighbors might object to the aesthetics.
I'm sure most of these 223 small wind turbines are quite suitable for home use.
i'd hit it so hard, if you pulled me out you'd be the king of britain [bash.org]
There are other ways to do the same thing. Rather then switching in and out coils another approach is to switch the coils on and off. In light winds the cils are only in use 10% of the time andthen when the wind is blowing the coils are on full time. You switch them rapidly, several times per second. houshold dimmer switches for lights and many motor controlser work this way.
I think what these guys have found is the "coils are cheap". so they use way more coils than are needed but the contoller then becomes much simpler.
> What do you suppose would happen if we invested that money into domestic
> energy sources like wind and natural gas?
We are about to find out. You won't like the answer I suspect.
> Job creation and economic growth perhaps?
Probably not. Not much chance of getting energy at a lower price per unit out of any of this 'alterantive energy' stuff anytime soon. Otherise it wouldn't be 'alternative.' Besides, the second something looks like it might get practical the usual suspects align against it. Hyrdo? NO! Geothermal? Already got protesters firing up over that. Wind? NIMBY! Kills birds, and so on.
> This is a national security issue in addition to being an environmental one.
Agree 100%, which is why I don't think this is a good time to gamble on what might be when the solution is so simple a caveman could do it and requires no hoping.
Step One: DRILL EVERYTHING that looks like it has a reasonable chance of profitable production. We have to have energy in the short term and handing money to our enemies is insane. Short term we need petro fuels. Ten years from now cars being sold today are going to be on our roads and they will need fuel.
Step Two: Execute the enviromentalists for treason if it takes it but blow out the obstacles to safe nuke plants. Build hundreds of pebble bed and other safe designs. Not in twenty to fifty years, in ten. Build like we were going to war. Or better analogy, build like we did when we were trying to beat the Russians to the moon. Ramp up the transmission system to handle the extra load. Do recycle the spent fuel, again shoot the bastards if they won't stop protesting. This IS a national security crisis and we need to start acting like it.
Step Three: Now that electricity is cheap and falling in price the government must DO NOTHING. Don't attempt to pick the winners and losers, let the market figure out whether using the cheap power to make hydrogen is the right path or whether better batteries for plug in electrics are the way to go. Perhaps it is something we haven't thought of yet that will be the most practical in the end. Make electricity cheap enough and the invisible hand will point the way.
Step Four: Now that we have at least a couple of hundred years before the Uranium supplies start running low we can move on to solving the problem once and for all by dumping R&D into fusion. When that runs out, hell that will just have to be somebody else's probem.
Democrat delenda est
And for the obligatory car analogy, it is like running with only some of the cylinders when cruising, but all when climbing hills, except backwards. Slower wind speeds cannot drive the turbine with the drag from spinning all the coils. Turning off some of the coils means that the slow speeds are producing something, rather than nothing, because there is less drag at those speeds. It also means that turbines can be built to be efficient at higher speeds by adding more coils than old designs could drive, to milk everything possible from high winds. And, of course, now that he summary has explained it, it is obvious, and should have been done, long ago. Actually, with steam turbine-driven plants like nuclear or coal-fired, they DO do something like this by having high pressure and low pressure turbines. Also, big hydro-electric plants like the ones from the 1930s and 40s also do this, except that they turn off the flow into turbines that they do not need (since hydro plants are actually much better at modulating their output to match what the grid needs, while remaining efficient).
The big nelected factor in most reports is the effect on sunlight at the beginning/end of the day, when the ambient light is flashing because of the blades.
All intents and purposes. Not intensive purposes.
not to be nitpicky or anything but isn't the problem the lack of ambient light at the end of the day and the fact that the low angle of the sun is more likely to cause direct sunlight to cut through a turbine rotor disk causing what is commonly known as shadow-flicker?
so now we only discuss the summary and not the article? I guess its more honest....
I have a revolutionary idea which might accomplish something similar. I'm thinking of calling it a "gear-box"
http://www.youtube.com/watch?v=lNZqNL4qZxY
I live in a house with no double glazing, on a street where youths in pimped-up shopping trolleys regularly make a right racket outside my front windows.
Please don't give the little buggers any ideas - it's enough of a pain having to go outside and threaten them as it is :o)
One swallow does not a fellatrix make
The rotor is an electromagnet with a fixed resistance, so varying the voltage will increase the drag.
That's a 'full stop' in English, you pedantic colonial twat.
I'd like to see the patent for this (if one even exists), because I have a design sitting on my hard drive from over three years ago for this exact concept.
Actually, the design as stated in the article and summary sounds less efficient than switching coil arrangements. This "breakthrough" just switches coils on and off.
"I assumed blithely that there were no elves out there in the darkness"
Fluid dynamic concerns limit the efficiency of any wind turbine, using any mechanism, to about 59%. This is a theorem of fluid dynamics, much like you cannot exceed the carnot efficiency of a heat engine due to thermodynamic concerns, you cannot build a perfect wind turbine due to fluid dynamic concerns. The reason for this is fairly simple. If you achieved 100% efficiency it means you extract 100% of the energy, so the air behind the turbine should stand still. However, unless you have air accumulating in the turbine ( you don't ) an equal amount must enter the turbine as leaves it. The consequence is that the slower air stream behind the turbine must be wider than the incoming air stream. It takes a bit of math to show it, but in the ideal case you end up just short of 60% efficiency. I guess depending on how you count you could consider that a 100% increase over typical values of 30% , but you will not be getting anywhere above 60% efficiency and certainly not 100%.
You're actually picking at me saying the Phantom is not a real console? Seriously, you're giving them an out because they technically did make one box that could download games?
A parallel situation to the story at hand would be if they said they got 50% efficiency AND the thing would be available next year to buy, next year rolls around and they release a clip of a jet engine turning a windmill and that's it.
Anyway, lets not get into a semantic argument, the point is that pictures of the thing would be nice to look at but ultimately they don't amount to beans. Not having them is not a reason to assume it's not real.
Efficient in terms of energy produced versus energy available. Not energy into the generator versus energy out.
With current windmill designs the windmill is not generating electricity in very high and very low wind conditions. Currently, windmills run only in medium wind conditions. Other times the windmill could be in a brake position to protect it. With the invent of this new generator, the windmill can produce energy at lower wind speeds and the medium wind speeds.
But wind turbines already optimize torque consumption of the generator. This product was clearly developed by a non-engineer. It's a 100 year old concept. By controlling the number of coils in use you have only a discrete number of torque demands, but modern wind turbines have infinitely variable torque demand.
Will it? What about the losses in electricity distribution? If it's windy in New York but not windy in Los Angeles, can you send the necessary gigawatts of power all the way across the country?
For the "it's windy somewhere" idea to work, you need superconductors going across the country so that you don't lose large amounts of power. And currently, it takes too much energy to make a superconductor, so it still won't work. If somebody could invent a room-temperature superconductor, or some other form of long-distance lossless electricity transmission, then building wind turbines all over the place will work.
as far as i can tell, this technology has nothing to do with Betz' law or the theoretical efficiency of a wind turbine. in fact it has nothing to do with the design of the fan blades or rotor efficiency.
instead, the innovation here is replacing a mechanical transmission with an electric one. this allows the turbine to perform optimally under a wide range of wind speeds. this could just as easily be applied to gasoline engine power generator or other non-turbine/fluid-mechanics-related power generators.
it's like being able to switch out the transmission depending on the wind speed. we already have separate generators that operate optimally at low speeds, medium speeds, and high speeds. this is just a cheap & simple way to incorporate multiple performance ranges into a single electric transmission.
Maybe this could be applied to your car's alternator, I don't know.
I don't think it necessary to use that in a car since in the car we are using DC power not AC power. The AC output frequency does not affect much the bridge circuit to convert the AC to DC.
Wow, to think that all these years the wind-power industry could have been asking slashdot instead of wasting all that time and money on research! Don't worry, I'm going to forward this entire thread to Vestas, GE, Enercon and the rest. I'm sure they'll be delighted to learn that slashdot has enroled their best minds to help with this problem.
You're attempt at making a snarky comment regarding slashdotters thinking they're smarter than people working in the field is, to put it mildly, an EPIC FAILURE, seeing as how I'm not saying anything that hasn't been known in the field for a long time, nor am I claiming too. On the one hand, I'm describing things that are already done in deployed windmills, and on the other hand I'm describing the motivation behind this new invention.
I have no idea what made you think this was my attempt at engineering a better windmill, rather than explaining the principle behind what's already been done by clever engineers.
But I feel safe assuming it involves stupidity, and probably insecurity. Good show.
The enemies of Democracy are
Except that the power available in the wind is related to the cube of the wind speed
(energy = 1/2 * m * V^2) --> twice the V means twice the mass going by * V^2 so third power...
5 mph to 15 mph factor of 3 in wind speed, factor of 27 more power.
if it was 2 MW at 5 mph then it would be 54 MW at 15 mph.
And 1458 MW at 45 mph...
There's nothing wrong with running low RPMs in high winds. Even though the generator is turning the same speed as it would in lower winds (and thus producing the same voltage) the higher torque generated will allow the generator to push more current.
Look at the power curve chart here:
http://www.clipperwind.com/techspecs.html
Between the upper and lower wind speed limits (which are aerodynamic and mechanical limitations, not electrical ones), power output scales with wind speed in a pretty linear fashion.
I see the value of the new generator being primarily in small-scale fixed pitch windmills.
"Prefiero morir de pie que vivir siempre arrodillado!"
This article is about staying close to the ~59% theoretical maximum predicted by Betz' Law over a wide range of incoming wind speeds, not magically eclipsing it. Save your sarcasm until you really know what you're talking about.
http://www.windpower.org/en/tour/wres/betz.htm
All 19 hijackers were known terrorists 09-10-2001. Lack of FBI intelligence does not justify warrantless wiretaps..
I was actually referring to the entirety of all posts on this topic but I made the silly mistake of replying to the last post I read which I guess I was sort of agreeing with as the person you were quoting was attempting to reinvent pitch control.
Sorry I upset you so very much.
Spelling, don't leave home without it.
Sorry mate. I agree with you, the GP is an idiot, but I just had to.
February 9th, 2009 8:55pm: Slashdot becomes self-aware.
Betz's Law - Pmax = 16/27*1/2*rho*v^3*Area - is the max extraction you'd get from the wind. Kinda like that whole second law of thermo thing... a little tricky to get around (but if you do you'd be rich). But don't take my word for it, confirm it for yourself.
Exactly. For a given density of coil to the strength of the permanent magnet, there is a force resisting the torque applied by the turbine. If you could vary the strength of this force (by changing the number of coils) you could ensure that the turbine was always able to spin regardless of how low or high the wind speed. It would also work on the upper end, where strong gusts typically overrun the alternator (the fields create destructive interference) by allowing more force to be applied slowing it down to the optimal rate. FURTHERMORE, it could be done in such a way to perfectly sync the alternator with the grid without requiring any type of inverting, wave sliding, etc, which is a major loss point.
Cool! Amazing Toys.
Ah, well, I considered that possibility, but discarded it for the sake of a good flame. So not upset, until I found out that my flame was itself failure because I misunderstood what I was replying to. :(
The enemies of Democracy are
Wind speeds differ. Blades that will start in low winds will not go fast in high winds. Coils that will produce lots of power in high winds will not start in low winds.
Blades and coils do not change after they have been manufactured. Normally.
"I assumed blithely that there were no elves out there in the darkness"
The starting friction on your gearbox makes it impossible to use on small scale windmills in low winds. The 10% thermal losses it generates, along with the energy required to switch gears, makes it less efficient. Finally, the cost of machining custom gearboxes for various sizes of wind generators in various wind conditions makes it a completely impractical alternative.
"I assumed blithely that there were no elves out there in the darkness"
Actually, many sailing yachts use small wind generators to charge their batteries (generators are heavy, noisy,smelly, and need fuel, and many yachts don't have space suitable for sufficient numbers of photovoltaics). While the power produced would be quite low for the standards of a US home (many yachts are fine on a kilowatt-hour/day or less), there's no particular reason they couldn't be built a little larger, a little heavier, and used to produce AC power for homes. A more efficient generator would be a big help.
There's no place I could be, since I've found Serenity...
Would this work in an engine? Is someone already doing it? Maybe changing the number of electromagnets in use to spin a motor could be used in lieu of gears to achieve different levels of power at different speeds in a car?
That's just like a design I made for charging supercapacitors off wind power: a gear-less wind-driven generator with a large diameter radial coil pack. When the capacitor charge is low (and therefore the voltage is low as well) the coils in one phase are connected in parallel to provide a high-current, low voltage charge. When the capacitor voltage starts to rise above a threshold the some coils are switched from parallel to series, raising the voltage (but lowering the amperage). The more the capacitors get charged, the more coils get switched from parallel to series until either the preset maximum voltage is reached (meaning the capacitors have reached full charge) or all coils (in a phase) are connected in series.
The same trick can work for giving a low start speed wind generator for conventional accumulators but in that case you might want take some coils out of the circuit to raise the speed above the charging threshold. As soon as the wind picks up those coils can be added back in the mix.
--frank[at]unternet.org
It's called Maximum Power Point Tracking (or MPPT) and has been around for a long long time.
Since there is mention of 'windmill efficiency' that talks about the end-to-end efficiency, which includes Betz' limit.
Simply restated getting ~60% of the power going in to the system as a whole can be harvested (100% - Betz' - losses), at low power levels you'll need some trickery to maximize this (think of it as impedance matching) but this is not in any way 'new'.
One commercial gearbox less machine in the 2 Megawatt range is the Enercon, it features MPPT.
MP3 Search Engine
If you do some research into wind power, you will see it is exactly the problems with putting 2MW low rev capable gearboxes at the top of towers that has led to this electrical solution. Wind turbines turn very slowly, hence the tooth loading on any gearbox, planetary or not, is enormous. Remember that at any given time the entire loading is on one or two teeth per gear, and that includes shock loads which are worsened because of the inertia of the rest of the gear train. What's more, your solution requires a 90 degree bevel drive, and these are very difficult indeed, as well as expensive, to engineer well at high powers. (The low speed gearbox problem is one reason that ships are propelled by very low speed direct drive Diesels; to get the desired low prop revolutions it is actually better and more efficient to make vast longstroke engines doing around 75rpm than to gear down physically much more compact medium speed engines. Even crankshafts 300mm in diameter sometimes break in heavy seas. Imagine the loading on a single gear tooth.)
From scarped cliff or quarried stone she cries "A thousand types are gone, I care for nothing, no not one."
When the wind really kicks in and pushes the grid to its limits, other parts have to lower production. In our case, this means letting a lot more water spill over the dams. This, in turn, tends to introduce way too much nitrogen into the water, which harms the fishies. Or so goes the theory.
Unless there is nitrogen in the spillway - why would there be more nitrogen in the water?
The water going over a dam goes either through the turbines or through the spillway. All they're doing (when they don't need to run as many turbines) is to divert water that would go through turbines to instead go over the spillway.
(The amount of water that flows past the dam, either through turbines or spillways, is determined by the level of water in the reservoir combined with the amount of incoming water from the source streams/rivers. If the incoming water feeds are too large, and the reservoir is already close to capacity, you have to allow that excess flow to bleed off at a faster rate then normal.)
The problem is not that letting more water over the spillway causes more nitrogen. The problem is that there was more nitrogen already in the water when it entered the reservoir. Which probably points back to either local industry or farming.
Wolde you bothe eate your cake, and have your cake?
Seriously, how much does the kdawson shell script earn from posting these "ZOMG startup brakes teh laws of physaks!!!!! agin!!!!" pieces?
If you were blocking sigs, you wouldn't have to read this.
Yes, this is a slight twist on regenerative electric motor braking in many electric cars and motorcycles. Harder you tap the brakes, the more coils switched on.
However, inrush currents can shorten the life of coils, and the switching diodes weaken - think computer switch mode power supplies.
I believe pitch adjustable blades, and a thing called inertia work 97% efficient, so adding regen may potentially add percent or so tops.
Awards for viscous fluid clutch controllers are better - cheap, reliable, proven, along with a huge stone flywheel, works plenty well
Anyway, lets not get into a semantic argument, the point is that pictures of the thing would be nice to look at but ultimately they don't amount to beans. Not having them is not a reason to assume it's not real.
You also have to realize this is /. and therefor we CANNOT RTFA, we can only skim it for pictures like children.
On a more serious note, we are taught to be skeptical of everything, learning that anyone can say anything. Trying to simplify fact finding by saying if there's a picture, then it's proof (or at least more proof). Although when it comes to new technology and pictures; 50% is some cgi, 25% of them are just look-a-likes(that may or may not do what it says. So what, it 'looks' like a wind turbine) and 25% are the real prototype, and yes I pulled those figures from thin air.
Disclaimer: I am not god.
We may not be created equal
But we can be treated equal.
Thank you, that makes sense.
Cheers,
"What in the name of Fats Waller is that?"
"A four-foot prune."
Old Zeno saw this coming a mile away. Every time you make a 50% advancement, you get closer to your goal, but no matter how many times you do that, you never make it.
Ergo, we should look askance at 50% improvements.
Know your pads. One time pad: good for cryptography. Two timing pad: where to take your mistress.
People have actually played it.
Gamers.com went hands-on with it in 2004/2005 I believe. It physically existed. It physically worked. Whether or not that was all a hoax doesn't matter - the easiest hoax would be some shoddy software running on a windows box with some sample shitty pc games being served to it. (Hint: That's exactly what the Phantom was designed to be!)
It fucking existed. It was shit, and it was probably a money grab given the boasting and the non-delivery.
But it existed.
Ok, plans will only be posted for users of electric winches and giant inverters...
There was an announcement in the past few days of a verticle wind generator that could be used in your back yard.
Don't forget about the ambient low pressures killing the bats.
"In May 2007, the US National Research Council published the results of a survey of US wind farms showing that two bat species accounted for 60% of winged animals killed. Migrating birds, meanwhile, appear to steer clear of the turbine"
http://www.newscientist.com/article/dn14593-wind-turbines-make-bat-lungs-explode.html?feedId=online-news_rss20
Nitrogen in the air supersatures the water when it is spilled. This doesn't happen when the water passes through the turbines because it is never exposed to the air (at least not to nearly the same degree). Do a quick google search for "nitrogen supersaturation dam spill" and you'll find more than you ever wanted to know. The phenomenon appears to be very well documented. What is less clear is whether it really has a net negative impact on fish (because spilling water has other beneficial aspects for fish).
How about regenerative breaking? That fits the bill. And last I checked, it was hard to top 65% on consumer vehicles.
I know tobacco is bad for you, so I smoke weed with crack.