From the American Institute of Physics
Using fluctuating wind power
Incorporating wind power into existing power grids is challenging because fluctuating wind speed and direction means turbines generate power inconsistently. Coupled with customers’ varying power demand, many wind-farm managers end up wasting power-generation capacity and limiting the service life of turbines through active control – including fully stopping turbines – in order to avoid any possible damage to the power grid from spikes in supply. In a paper published in the American Institute of Physics’ Journal of Renewable and Sustainable Energy, researchers propose a new strategy to optimize power-generation efficiency and so better control wind farms.
The new strategy is based on continuous predictions of how fluctuating winds affect each turbine’s maximum generation capacity. It also incorporates factors missing in other wind-farm control strategies, including differing power generation between turbines, actual fluctuations in power generation capacity, errors in prediction, communication disruptions preventing active control, and even turbines without the capacity for continuous active control. To demonstrate the feasibility of the new strategy, the researchers compared their predictions to raw data from a single wind turbine. The team then further refined their calculations and simulated a control operation with data from a wind farm of 33 turbines.
The results suggest that wind-farm managers can improve their power-generation efficiency with the new strategy. However, the researchers caution that before implementing the strategy, each wind-farm manager should adjust the underlying parameters – such as how often to adjust each turbine’s speed – based on local conditions.
Article: “An Active Power Control Strategy for Wind Farm Based on Predictions of Wind Turbine’s Maximum Generation Capacity,” is published in the Journal of Renewable and Sustainable Energy.
Link: http://jrse.aip.org/resource/1/jrsebh/v5/i1/p013121_s1
Authors: Dewei Liu (1), Jianbo Guo (1), Yuehui Huang (1), Weisheng Wang (1)
(1) China Electric Power Research Institute
Related articles
- Rethinking wind power – Harvard study shows it to be overestimated (wattsupwiththat.com)
- Research suggests scientists have overestimated capacity of wind farms to generate power (eurekalert.org)
- Protesters say turbines will disrupt migratory patterns of swans near Grand Bend (lfpress.com)
We already are a good ways along with that, too. What you do is use a conventional fuel cell that uses natural gas. You enrich the natural gas system with hydrogen. The gas distribution system is already being made “hydrogen tight” which is VERY difficult to do. Hydrogen is very small and leaks from the smallest of imperfections. Then you deploy nuclear power for water desalinization and hydrogen production when you have excess power not needed for the grid. You inject the hydrogen into the natural gas system, release the O2 to the atmosphere and you basically use the gas distribution system for what amounts to a water distribution system. The fuel cells in a place like Palmdale, CA would produce water as a waste product which could be used for toilet flushing, lawn irrigation, etc. Hydrogen is easier to move over hundreds of miles than water is. The atmosphere moves the oxygen for free.
I’m reluctant to be a party pooper on the promise of pumped storage for all the huffers and puffers out there full of wind BUT…
http://en.wikipedia.org/wiki/List_of_pumped-storage_hydroelectric_power_stations
We have already grabbed Gaia’s low hanging fruit of pumped storage largely for our coal fired generation system whereby excess steam turbine generation capacity when we’re all asleep is used to pump our daytime hydro uphill again.
Notice that Tumut 3 listing for Oz which is part of the massive Snowy Mountains Hydroelectric Scheme which took 25 years to complete and harnesses the main water source for our continent of droughts and flooding rains-
http://en.wikipedia.org/wiki/Snowy_Mountains_Scheme
The only other reasonably efficient use for wind energy is desalination and we rushed to build expensive desal plants in response to a long General Drought that could utilise wind power effectively only to find the whole country was flooded with water. Such are the vagaries of Gaia and the best laid plans of mice and men.
Could too much wind power wreck our electric grid? Maybe the windmills need to be articulated — fixed atop the towers so they can be pivoted to position the generator and its blades in a manner that allows rotation either in a horizontal or vertical plane.
In normal operation, wind would blow against the blades, rotating them in the vertical plane. Then if the wind blows too hard, instead of feeding too much wind power into the grid, some of the power can be reconnected, shunting it into a group of ground stakes that have been driven into the earth surrounding the tower. This should heat the land below the windmill, thereby storing the power for later use.
Then when the wind is dying, the pivoting mechanism can reposition the windmill blades into the horizontal plane. Now the windmill can be rotated by the rising air currents from the previously heated earth below. OK, so this concept for storing wind power may not be too practical during wintertime, but how about during a torrid summer? Would adding solar radiation to the stored windmill-supplied heat help to rotate the horizontal blades, and turn this into a sort of green utopia — a combined solar power and wind power generator?
Still not to too practical? Why does anyone to imagine that anything about windmill power is practical for powering our electric grid?
Regarding solar and wind power naturally balancing each other. This clearly will not work for much of the world due to the issue of peak power demand in the winter. For example, in the upper Midwest of the US, winter power demand peaks often approach, and sometimes exceed, summer pwer demand peaks. Winter power demand peaks typically occur from 4-7 pm during weekdays when it is cold outside. Is it always windy at 4-7 pm in the winter? No. And, I think we can confidently predict there will be no solar power produced after the sun sets.
Regarding the use of pumped hydroelectric storage, it is almost impossible, if not impossible, to get a new, large hydroelectric power project built in the US. The last major pumped storage project to be constructed in the US of which I am aware was built in Michigan decades ago. It was a couple of hundred MW, only capable of providing a little ‘peak shaving’ for the Chicago metropolitan area.
The US Pacific Northwest (PNW) has huge hydroelectric capacity and also excess wind power generation during the spring snow melt season. So why doesn’t the BPA, just reduce hydroelectric generaton, conserving water for times when the wind isn’t blowing, because other environmental restrictions (primarily minimum water release requirements to help maintain the Salmon population) force the BPA to release lots of water regardless of whether or not the wind is blowing.
It’s even worse than that. BPA has to dump water without generating power when the wind is blowing. The vast windfarms of OR & WA are a huge boondoggle, worse than worthless from the standpoints of energy, the environment & economics, a fact known even to those who benefit from the taxpayer-subsidized royalties paid to landowners.
As for the proposed Antarctic windfarms, there is this:
http://www.meridianenergy.co.nz/company/news/media-releases/wind-farms/antarctic-wind-farm-exceeding-expectations-for-antarctic-bases/
Notice total lack of comparative cost analysis, beyond petroleum presumed saved. At least penguins, unlike flying birds & bats, can’t be killed by the blades, unless they fall over.
http://wattsupwiththat.com/2013/03/03/impractical-proposal-dry-ice-sequestration-on-antarctic-ice-sheets/
I agree Crosspatch. The cloud is a wealth of information which can make the decisions based on multiple parameters accessible through the Internet. The way forward needs to be cost effective… and the cloud enables natural software sharing capabilities rather than local customer software,
Greg,
according to data given here …
http://content.caiso.com/green/renewableswatch.html
… there is almost no correlation (<1%) between demand and wind power. The correlation between demand and solar power is around 30% only. You just happened to pick a lucky day it seems.
So no reasonable way at all to scale and combine these sources to meet demand.
Greg,
according to the source you took your sample data from, the correlation between wind and solar generation is negligible … sometimes even slightly positive.
Here’s a new battery developed at MIT. TED talk. Reminds me a bit of Savory’s on desertification.
http://video.mit.edu/watch/ted-talks-donald-sadoway-the-missing-link-to-renewable-energy-10635/
The problem with mechanical energy transfer systems, pumped storage, flywheels, 1000-mile pipelines, etc., is the friction losses. In the case of pumped storage, the losses are on the order of 50%. So, yes, you can have wind turbines producing a constant energy supply, as long as you roughly double the number.
davidgmills:
Thankyou for your post at March 26, 2013 at 6:00 pm that links to the ‘TED talk’ by Donald Sadoway. I had not seen it.
Sadoway provides a short and entertaining talk about the liquid metal battery which he is developing, and it seems to show some promise. I sincerely hope his work proves successful. But I await further developments before I am convinced.
At present he has scaled- up from a 1 Wh battery to a 1 kWh battery. This thousand-fold scale-up is impressive but much, much more is needed. Sadoway provides a pretty picture of an imagined 2 MWh battery which could fit into a standard transport container. Pictures are easy to produce, but scaling from 1 kWh to 2 MWh storage may not be. Indeed, his system generates heat to melt the metal to liquid, and controlling the generated heat in the postulated 2 MWh system would not be easy.
As yet there has been no publicity about a prototype 2 MWh unit although his talk was in 2012 so at least three months have passed since his TED talk. The fact that he made the ‘Ted talk’ demonstrates this lack of publicity about a prototype is not because development of the prototype is a commercial secret.
Clearly, Sadoway is a good salesman. He is an MIT professor who started with an idea, obtained funds from MIT for research using one assistant, then obtained funding from Federal Government and industry to create a research team of 20 qualified personnel. Now – he says – he has established a commercial company – which he owns – to continue the research.
Incidentally, in his talk he claims his work is “without subsidy” but that is not true according to his own statements in his talk. To date his work has provided no income and is subsidised 100% by Federal Government and speculative investment from industry.
The benefits of a cheap, large energy store would be immense (this is explained in my above post at March 25, 2013 at 4:45 pm) so the relatively small investment in ‘blue sky’ research of this kind is a good risk for government and industry: probability of success is small, but cost of seeking the success is also small, while benefits of obtaining success would be huge.
It is to be hoped that Sadoway’s R&D proves successful and his work merits support. But, at present, his excellent salesmanship should not blind people to the high probability that his battery will prove to be impractical at commercial size. If such a large battery were easy to build then it would have been done because the benefits of building it are so large; i.e. it would remove about a third of the need for existing generating capacity.
Richard
Here is one of the latest ‘tricks’ to integrate variable electricity sources and a very good rebuttal. Included are other items that are must reads as promised from my earlier post here on
March 25, 2013 at 2:32 pm.
http://dailybail.com/home/why-wind-power-wont-work.html
California ISO and Pacificorp enter MOU on Energy Imbalance Markets
On February 12, 2013, the California Independent System Operator Corporation (CAISO) and neighboring utility, PacifiCorp, entered a Memorandum of Understanding to cooperate on the development of an energy imbalance market (EIM) in each entity’s respective balancing authority areas, in the hopes of laying groundwork for a broader effort across the western region. Hailed by the CAISO as the “first step in bringing PacifiCorp and ultimately other Western balancing authorities into an automated real-time [five]-minute dispatch system” the CAISO and PacifiCorp agreed in the MOU to work towards implementing the EIM by October 2014.
Energy Imbalance Markets will raise prices in the West
Some western energy markets are currently challenged by the increased development of variable renewable energy resources (i.e., wind and solar that vary depending on the availability of the resource and therefore must be integrated onto the electric grid whenever they are available, day or night) promoted through federal tax incentives and renewable portfolio standards in some states. Many of these resources are under development even though the economic recession has reduced the need for electric generation in many areas in the West.
john from DB
@richardscourtney: Thanks for your input and healthy skepticism. I have no proper background to judge most of the technological ideas that people have. But I read 10 or more hours a day and have for thirty plus years, so I come across a lot of promising sounding ideas. When I do, I just like to call attention to them so that others more qualified can judge.
Here’s what I appears to me to be the most promising: Liquid Fluoride Thorium Reactors. Invented at Oak Ridge, tested and proven, extremely safe, hard to turn into weapons (which is why it was deselected by the government that wanted dual purpose reactors) and with a far more abundant nuclear fuel than uranium. The nuclear power we were supposed to have. A TED talk on thorium:
And the best video on it but much longer:
davidgmills:
re youir interst in thorium reactors in your post at March 27, 2013 at 8:00 am.
Yes, thorium power may have some advantages but adoption of it at commercial scale is inhibited by novelty risk. Similarly, novelty risk inhibits adoption of the several clean coal technologies for power generation (i.e. AFBC, CFBC, PFBC, ABGCC, IGCC, etc.).
However, China is interested in thorium power and normal investment considerations do not apply there and so China may provide a 3-decade commercial demo. of thorium power which would remove (at least, severely reduce) the novelty risk. This is similar to the commercial PFBC power station at Cotbus, Germany, which has now been operating for two decades: one more decade of successful commercial operation of that plant would significantly reduce the novelty risk – so the cost of obtaining money to build – commercial PFBC plants.
Fortunately, we have adequately efficient and safe conventional nuclear technology so the need for thorium technology is not great. Conventional nuclear is an appropriate technology for power generation especially for providing baseload.
Much, much more interesting is the liquid metal battery technology which you drew to my attention. In the very unlikely event that this technology proves viable at commercial scale then it would be rapidly adopted because its benefits would be large, several and immediate. Importantly, the unit size of the batteries would be relatively small so many individual batteries would be required with reduction to novelty risk. I explain this as follows.
A power station has a scheduled life of at least 30 years (and much longer life with extensions). The capital cost of the power station is recouped during the first years (often the first 15 years) of its life, and good profits are made after that, There is severe novelty risk with a new technology power station: the return on investment would be much reduced if the novel power station were – for some unforeseen reason – to reach the end of its usefulness prior to the end of its scheduled life. Hence, the monies borrowed for construction of a novel power station have a high interest rate to compensate for this risk that the novel power station is untested for a complete life schedule.
As a power station reached the end of its scheduled life then it could be replaced by the putative batteries. There would be very many batteries and if they were to start failing prior to their scheduled life then it is unlikely that all would fail at once: one would fail first and then the rate of failure would increase. As the failures occurred then the needed replacement rate could be assessed with a view to determining if the battery technology should be abandoned in favour of a conventional power station. But there would not be a sudden end to return on investment; instead, there would be a reduction to obtained profits provided by the cost of replacing failed batteries.
There is an anology which may help understanding. Lenoir invented the first internal combustion engine in 1860. Otto and Daimler developed the 4-stroke engine in 1876. Oil became largely available around ~1900. Ford produced the Model T which was the first first cheap automobile and produced ~15 million of them from 1909 to 1927. The cheap unit cost of the Model T induced rapid replacement of horses for transportation. If the automobile had needed 7 million cars to instantly replace horses then the rapid adoption of automobiles would not have happened.
The small unit cost of Model T automobiles spread the risk of adopting them between the individual units and over about two decades. Similarly, the small unit costs of the batteries spreads the investment risk over individual units and over time.
I hope this was of some interest and use to your investigations.
Richard
@richardscourtney. One of the things that makes thorium so exciting is that it can be scaled very small as well as very large. It has the ability to be used on small islands, for example where other power generation is a real problem. So it might get over the novelty risk real fast. The intent is to make them on an assembly line like a Boeing aircraft. Vastly different than nuclear now. Thorium’s other real advantage is that it can use nuclear waste to kickstart the reaction and burn up the waste we have been producing. It also generates its power at normal atmospheres so that the risk of water under extreme pressure is eliminated. I know the Chinese will unfortunately beat us to market. I would hope that we make these reactors as well because we need the jobs.
1. Wind turbines are medieval technology. The Dutch have used them to reclaim land from the sea by pumping out water since the Middle Ages. Modern turbines are bigger and shinier, but they are fundamentally the same.
2. They don’t produce very much electricity for the investment.
http://www.instituteforenergyresearch.org/denmark/Wind_energy_-_the_case_of_Denmark.pdf
3. Pumped Storage is not a solution to the intermittentcy problem of wind power:
“Do the Math: Using physics and estimation to assess energy, growth, options” by Tom Murphy professor of physics at UC San Diego:
“It is clear enough that pumped storage exists and works quite well in certain locations. But demonstration does not imply scalability, and scaling the existing installations did not deliver a radically different answer (in fact, demanding more installations). The enormous scale I calculate means simple factors of two or even ten here and there do not change the overall flavor of the conclusion. Let’s be clear that I am not making any claim that large scale storage at the level we need is impossible. But it’s far more daunting than almost anyone realizes.”
http://physics.ucsd.edu/do-the-math/2011/11/pump-up-the-storage/
And, every pumped storage project will be fought tooth and nail by the “environmentalists”:
http://en.wikipedia.org/wiki/Storm_King_Mountain_(New_York)
“In 1965 the mountain became the focus of a landmark environmental battle when local activists formed the Scenic Hudson Preservation Coalition (today known as just Scenic Hudson) to fight against plans by utility Consolidated Edison to cut away part of the mountain near the river and build a pump storage power generator complete with transmission lines across it for an ambitious power generating scheme which would also have entailed creating a reservoir in much of what is now Black Rock Forest. In a lawsuit brought by the coalition, a judge ruled for the first time that aesthetic impacts could be considered in such projects. In 1979 Con Ed finally abandoned even a greatly scaled-down version of the project, and settled a parallel lawsuit brought against their Indian Point facility by agreeing to endow the Hudson River Foundation with $12 million.”
Walter Sobchak:
At March 28, 2013 at 9:08 pm you say
Actually, wind turbines are a much older technology than that. And, following thousands of years of development, the use of wind turbines was abandoned when the much greater energy intensity in fossil fuels (than in usable wind) became available by use of the steam engine.
There are a number of types of wind turbines. They are divided into Vertical-Axis and Horizontal-Axis types.
Vertical-axis windmills to mill corn were first developed by the Persians around 1500 BC, and they were still in use in the 1970’s in the Zahedan region. Sails were mounted on a boom attached to a shaft that turned vertically. The technology had spread to Northern Africa and Spain by 500 BC. Low-speed, vertical-axis windmills are still popular in Finland because they operate without adjustment when the direction of the wind changes. These inefficient Finnish wind turbines are usually made from a 200 litre oil drum split in half and are used to pump water and to aerate land (3). Low speed vertical-axis windmills for water pumping and air compressing are commercially available (a selection of commercial suppliers is at http://energy.sourceguides.com/businesses/byP/water/wPumpMills/wPumpMills.shtml).
The horizontal-axis wind turbine was invented in Egypt and Greece around 300 BC. It had 8 to 10 wooden beams rigged with sails, and a rotor which turned perpendicular to the wind direction. This type of wind turbine later became popular in Portugal and Greece. Around 1200 AD, the crusaders built and developed the post-mill for milling grain. The turbine was mounted on a vertical post and could be rotated on top the post to keep the turbine facing the wind. This post-mill technology was first adopted for electricity generation in Denmark in the late 1800’s. The technology soon spread to the U.S. where it was used to pump water and to irrigate crops across the Great Plains.
During World War I, some American farmers rigged wind turbines to each generate 1 kW of DC current. Such wind turbines were mounted on buildings and towers. On western farms and railroad stations, wind turbines for pumping water were between 6 and 16m high and had 2 to 3m diameter. With 15kmh wind speed, a 2m-diameter turbine operating a 60cm diameter pump cylinder could lift 200 litres of water per hour to a height of 12m. A 4m diameter turbine could lift 250 litres per hour to a height of 38m.
The above brief history demonstrates that wind turbines can have useful niches to the present day. For example, small wind turbines can be used to economically pump water or generate electricity in remote locations distant to – or disconnected from (e.g. on boats) – an electricity grid supply. But wind power lost favour when the greater energy concentration in fossil fuels became widely available by use of steam engines.
Wind power has recently found favour for large scale electricity generation in some places, but is completely uneconomic and impractical for the several reasons stated in this thread.
I wince when I hear environmentalists claim wind turbines need subsidy for their adoption because they are “new technology”. If wind turbines are “new technology” then the steam engine must be future-tech.
Richard
I want to thank Richard S Courtney for amplifying my point here.
Walter Sobchak:
Glad to help. It was my pleasure because your point is true and important.
Richard
richardscourtney provides yet another real positive feedback. Thank you sir… from most of us for providing cogent and balanced fact based information.