Environmentally sensitive energy production has come a long way in the past few years. Wind power, in particular, is in increasingly widespread use, with wind turbines operating throughout the world and exponential growth expected within the next few years.
However, hurdles remain. The most pressing relates to the inconsistent nature of weather and the need for a low-maintenance, economically attractive energy storage system.
There are three rotor blades in the typical wind turbine. The rotors, which can be adjusted continuously to respond to weather conditions, feed into generators to create electricity.
The ability of a turbine to optimize its performance in response to the elements is what makes it attractive as a clean energy source, but it can create waste. Most energy storage systems are designed to meet high power demands but occur in brief and scattered bursts. The rest of the time, battery-powered storage capabilities exceed the need of the turbine.
Ultracapacitors provide a highly reliable, cost-effective energy storage solution for wind applications.
When peak power needs and extreme conditions do occur, batteries show additional limitations. They struggle under moments of high peak power and perform poorly in low temperatures. In extreme conditions, battery operating life is limited, creating a situation where engineers and maintenance crews must frequently swap out components under potentially dangerous conditions. Of greatest concern is that batteries do a poor job of delivering the frequent, short power boosts wind turbines need to make rapid rotor blade adjustments and create electricity.
Alternatively, ultracapacitors offer a reliable option that performs well under a wide range of temperature conditions. These components, which reduce overall system size, have a far longer lifespan than batteries, making them a significantly more cost-effective choice for wind turbine design teams. As the market continues to grow, ultracapacitors will become increasingly important in wind-generated power production.
Beyond the capabilities of the capacitor
Most design engineers are familiar with electrolytic capacitors, which have a high power density but short time constants. Ultracapacitors also have high power density but can deliver high energy density, too, allowing them to store a vast amount of energy in a small package. Ultracap arrays offer time constants of the order of tens of seconds to minutes. The difference between the two components is significant, and applications that were not viable with capacitors are now feasible.
Great detail here, OhmsLaw. From everything you're saying, preventing bird crashes sounds very feasible. Wonder if we'll see a day when bird repellant devices will become standard parts of wind power systems.
Never mind, I went to Mouser who has become authorized Ioxus distributor (noting that Ioxus is still a startup) and this is also reflected in the fact that very few types of UC are actually available, the large prismatics are not available. The smaller snap-in UC can be supplied and there is even a round 3000F cylindrical unit, but its price is close to $100 per unit in quantity, so the cost is almost an order of magnitude larger than a solution with LiFePO4 cells.
I noticed that the smallest (100F) UC was below $10 in quantity so I decided to check its data sheet. It can handle a continuous 13A. Compare that to the 400A for the LiFePO4 cell at comparable cost and you can see where you should spend your money...
BTW, the large 3000F cylindrical cell can handle 145A continuous at a price almost an order of magnitude higher than LiFePO4 cells, while offering a lower continuous current rating. Why did we "need" UC again?
To me it sounds that they are trying to create a market by pushing articles about applications with catchy (but clearly bogus) titles and without supporting data in the article, because it looks like they lag far behind state of the art in other -established- technologies.
I hate to be so negative about an applicatoin of a green technology, but in this case I can't find any of the claimed benefits and all I see is an order of magnitude higher price without delivering any benefits. Please tell me why we would need this technology - I am not even trying to understand why this would make wind power "viable"...
Twice you refer to the high current required by blade pitch control stepper motors. Do you have a reference or even an order of magnitude for the power (current is irrelevant) required by these stepper motors? I would expect that the power to control blade position is several orders lower than the power generated by the turbine, so for a 1MW installation I can see that you need stepper motors or other actuators requiring in the order of 1kW for a relative fast response of pitch. But I have not seen a turbine design in 10 years, so please enlighten me. Note that for power levels like that we have plenty switching power supplies that run ordinary low ESR electrolytics.
The author quoted the use of UC alongside an (apparently) too low power lead-acid battery. Note that a more recent development is very low internal resistance Li-Ion batteries such as A123 where the cells deliver at least 20C continuous, which means that a tiny 20Ah pouch cell will deliver 400A without breaking a sweat. This means that a handfull of cells will cost you a few hundred dollars and easily deliver several tens of kW. I can't imagine that this will not be sufficient for even the largest blade positioning units.
Now I would like to hear a price quote from the author for a stack of 2 dozen UC which will support the same 48V nominal battery voltage as I just quoted.
Please note that the author uses arguments as that (flooded lead acid) batteries are too maintenance prone to be useful, only to describe that you need one UC along each lead-acid battery cell. So - apparently the maintenance is not reduced by adding UC, only the short term peak power draw is improved, at great cost and without benefit - no better maintenance or life. If instead the switch is made to LiFePO4 type batteries with low resistance such as from A123, then the maintenance issue does go away - they are supposed to live for 8 years and not require intermediate maintenance. Also the price would be very competitive over the lifetime compared to lead batteries, so the additoin of UC will only increase cost. If the UC can completely replace the flooded lead-acid batteries - yes, *then* the UC regain the advantage of long life and maintenance period - comparable to LiFePO4. But there still is the cost issue - the (large!) UC must have a cost in the order of $10 a piece or the LiFePO4 batteries win hand over fist...
Can the author give some expected pricing of the UC?
I think there are some key requirements to Wind Power systems;
Efficiency
Self-Starting thresholds
Regulation of wind spoliers for safety (passive)
Control of blade position for optimal harvesting of wind power. must react quickly to load and source fluctuations without affecting RPM quickly.
Short Term storage of surges from gusts
Short term storage of energy demand from high current stepper motors possibly used in blade position
Efficiency over a wide range of RPM, loads and source power curves
Low loss storage uner all voltage current ranges
Avoid a stall condition that could have been avoided in light wind.
Buffer large peak currents to the large blade pitch control system to regulate the power harvest efficiency
Low maintenance eleftrical, mechancial and electro-mechanical parts.
Long life MTBF in system and field replaceable components.
I think again the key attribute to improved performance is low ESR with dielectric storage capacity without checmical leakage and decay of capacity or ESR.
The cost/loss density ratio or Total Cost of OWnership and energy harvested
possible Efficiency Metric ?? = (Joules of storage) per $ / ESR power loss in transfer)
Lead acid may be longer life or cheaper but maybe not both.
UltraCaps appear to compete well in this area. Perhaps this may explain it. Lowest ESR.
Have to agree with Jerry, the article is speciously creating a high power requirement for blade pitch alteration, where the blade angle is rotated a small amount to better harvest the wind, usually by a small hydraulic motor or electric stepping motor, - or in the case of passive pitch wind turbines, no motor at all, just the pressure of the wind, and then arguing that lead acid batteries can't provide high surge current yet what do we start our cars with? - a tiny little 30amp battery that provides 4 or 500 cold cranking amps.
I have no formal studies , but I have personal test experience with various transient wave effects on bears, birds and dogs. As a Test Engineer who deveoped custom tests to find the weakness of all HDD's made during the 80's, it is similar to find the weaknesses to birds failing to avoid rotating obstacles and glass windows. I would be interested in reporting on all Aircraft BirdStrike activities and Airport Avariary clearance methods, but that would take more space than this blog.
http://www.batcon.org/ is one site with info.on bats I would expect radar jamming Bats with inband noises in ultrasonic range would disturb Bats enough to stay away.
If you need to install a wind Power system and the city is blocking it due to bat compaints, perhaps I can help conducting a local test to prove effectiveness in the area of methods I think would be affective..
It was my Dad who pointed out to me in 1967 since we lived under the glide path 360 @ YWG int'l airport, 1 mile from the airport, that all the migratory geese and ducks come within 1 mile of radar then make a sharp turn over our old house every year to the west away from city centre then sharp right north. and visa versa in fall. When I later studied Electrical Engineering in IEEE Microwave journals I saw the antenna patterns of bird feathers and then I realized how the birds could sense the Radar pulses rotating from the control tower antenna. 10 yrs later I heard stories from 60's about disk drives getting soft errors in skyscrapers of the Business District. They also were related to the Radar beacon colliding with raw R/W signals on shielded cables that did not work well at 4GHz or so.
I don't have sufficient data, but I believe from my EMC days of defining corporate standards for testing computer products under environmental stress (HALT , FCC and CE tests) that there is always a test I could create that could cause mysterious faults from modulated standing waves. So I learnt that the carrier frequency is not what causes direct interference but the modulation of pulses or in-band noise on the carrier. This applies tobaseband sonic pressures, ultrasonic, sonic, electromagnetic etc.
However adaptation to repetitive disturbances can lead to that being ignored, such as Polar Bears reacting to gunshots or explosions. They are highest on the food chain like and have no fear. Yet when surprised with light in the dark, they may run quickly in fear. So at night in late winter when I was manning a helix antenna aiming at our Black Brandt rocket launches in Churchill, I carried a flashlight, not a rifle and no food.
The great hunters of birds such as eagles, hawks and Owls and shotgun bearers, all have something in common in the methods used to create fear and that is one possible solution. Another solution I remember my father also using in the 60's was using a dead crow to keep noisy crows away and using a fake owl to keep trepidation birds away.
Bats are afraid of being blinded by echos that they cannot filter out. They are not disturbed by the clicks form other bats or the echos they produce. But false echos are akin to military radar avoidance methods. I am sure someone has found an optimal pattern and spectrum as an effective way of encouraging them to keep away. As we in technology would not want to create a magnet to harm bats from accidental injury with a 120mph Sivvonious blade! Its Bat enuf birds fly into Windows! But not Windows7 ;).
The article appears to be a classroom example of an advertorial, an advertisement that is written as if it is an independent article on some application, but the claim in the title (UC makes wind power viable) is not only ridiculous as wind power was long viable without UC and the claimed enabling application of UC in blade pitch control is not a very high power application since the movement (rotation) of the blades is minimal: short in duration and very intermittent, so there is no reason why the available utility grid at the wind power site (which needs to be capable of absorbing high power from the turbine output) would not be capable of delivering the short bursts of power at orders of magnitude smaller than the wind power itself??? Just having a 3-phase rectifier will guarantee you continuous DC power availability even without any Capacitors at all, so why would an UC be a component that makes it viable? The article has no data to support the claim, it just presents nice pictures of the editor's company products and general statements about wind power. So I agree - this article should never have made it to publication! my suspicion is - the only reason this article was published is because of the green that moved from the UC manufacturer to DN. Please prove me wrong and it was just a slow day at DN...
However, when you look at power requirements, how well do those lead acid batteries cycle?
----------- I was talking real storage. In that app, blade pitch, A123 lithioum batteries can do it for 10 yrs at far less cost. It should be interesting with the author giving us the cost, etc comparison in real numbers, $.
---------- For lead battery grid storage they use submarine type batteries that last 25+ yrs. So yes lead can last nicely.
In high cycle applications, such as wind turbine pitch control and hybrid buses, ultracapacitors are replacing lead acid and other battery technologies at a rapid pace. The demand for ultracapacitors is growing globally from a number of different applications, while the market is general has a CAGR of 42%. There is a reason that the market is growing,
------------ It's a wimp compared to A123's that do it at far lower cost, No? And yes hybrid bus UC's are a scam. Care to price one out vs A123's to show us how cost effective they are?
and it is not because of "scammers". It is because ultracapacitors are being used to replace the
environmental disasters called lead acid
------------- Lead batteries are the most recycled product on earth, 99.9% in the US. The one in your car is likely on it's 15-20th recycle by now as it's mandatory now by law. And it's value dead for recycling will keep it that way. Even dumped it mostly stays together until someone recycles it. No?
------------So what is your problem with lead batteries? Don't you have several yourself? Why? Are you a bad person because you do? Please explain?
That is great news. Now quote me some numbers backing your claims. What percentage of US wind power machines have such devices? Can you quote a study showing bird kill reduction? Has wind machine placement been modified to not intersect with raptor migration routes? Saying "I think" just isn't good enough.
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