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Stanford, California [RenewableEnergyAccess.com] Stanford researchers have produced a new map that pinpoints where the world's winds are fast enough to produce power. The map may help planners place turbines in locations that maximize power harnessed from winds and provide widely available low-cost energy.
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74 Reader Comments
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2 of 74 |
June 3, 2005
I don't want to get picky, but: "....80 meters (300 feet)...."? Who is rounding up, to the nearest 100 feet? The article author or the researchers?
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3 of 74 |
June 3, 2005
Specious argument -- how 'bout an analysis of how much land is loss to agricultural uses on same site as wind farm? How bout off-shore? What about land use for competing sources of energy (coal mines, oil fields, refineries, etc.).
In any case, clearly in article, it is stated that potential wind enegy in class III locations equals 72 terawatts. But, world electricity usage is 1.8 terawatts. So, divide your equations by 72/1.8 = 40. So, at least it's only 1/40th of the continent of Africa! (I find the 50 acres per megawatt suspicious) |
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4 of 74 |
June 3, 2005
72 terawatts is 72 million megawatts, so with a capacity factor of 25% that would require 144 million massive 2-MW turbines. At 50 acres per installed megawatt, that's 7,200,000,000 acres, or 11,249,950 square miles, about the same area as the entire continent of Africa.
So no, that's not puny at all. That's the problem. |
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5 of 74 |
June 3, 2005
72 terra-watts?!? That must be wind's "puny" contribution to the energy mix. I suppose that Senator Palpatine, uh, I mean Alexander didn't read Stanford's report.
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6 of 74 |
June 4, 2005
It's amusing that wind power gets so much press.
Wave power is more reliable and less of a sight-pollution strawman. Water is 800 times denser than air, so a wave power installation can generate much more power per square meter. There's a wave power installation on the Isle of Mann, and the Koreans are thinking big with a tide power project. A wave power gen could be as simple as a pair of rafts joined by a hinge. Put a water-piston pump on each raft and link them together to produce power. |
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7 of 74 |
June 4, 2005
The point is, wind power is not a practical large-scale solution. At 50 acres and a million dollars per installed megawatt (x4 per actual average megawatt output, which average 2/3 of the time it will be producing less than), it is not going to replace current electricity sources and certainly not the rest of our energy use.
Even most "renewable portfolio standards" being passed by states only aim to keep up with growing demand, not to "replace" existing (reliable) sources. |
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8 of 74 |
June 4, 2005
Yes, I made an error, confusing myself by also calculating the number of 2-MW turbines. 72 TW average load requires 288 TW of wind power at a capacity factor of 25%. At 50 acres/installed MW, that's 14.4 billion acres: two Africas!
Please note that I calculated the whole 72 TW because the first comment, like many gushing reports, including that of the map makers themselves, expressed how unpuny that was. I quite realize that actual electricity use, even all energy use, is much less than that. FPL Energy says that an installed MW of wind requires around 40 acres. The EPA has said 60 acres is likely. My own notes show a range of 30 to 70. So 50 acres seems a reasonable average. As for a c.f. of 25%, offshore wind facilities have yet to prove themselves, so far only showing more breakdowns. Any better record in some locations is diminished by the variability of wider geographic areas, and since we're talking here about the whole globe 25% is a realistic figure. |
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9 of 74 |
June 4, 2005
typo:
"Already there are % MW windturbines" should be 5 MW windturbines |
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10 of 74 |
June 4, 2005
Link would be nice!
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11 of 74 |
June 4, 2005
@ Rucio:
"Converting as little as 20 percent of potential wind energy to electricity could satisfy the entirety of the world's energy demands." So you need to start your calculation with 14.4 TW. So to cover the entire energy need you would need 57.6 million 2MW-turbines. (production factor of 25% is correct for medium qaulity land sites. At sea its a groce underestimation) This would mean 2304 million acres or 3.6 million square miles, to cover ALL (transport, heating, etc) of our energy needs with windenergy. In reality you will need less: At many sites the production factor is higher. Already there are % MW windturbines, 10 MW windturbines are expected to appear within five years. Much will be realised off-shore were production factors will be 40% or better. P.S. you made a calculation or writing error: you say 50 acres per MW, but you calculate 50 acres per turbine. |
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12 of 74 |
June 4, 2005
The use of TW in this article is rather confusing.
TW is a measure of power. It is not clear if they mean the nominal power of the windturbines, or the average power produced (which is lower) The use of TWh per year (i.e. energy) would avoid these problems. |
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13 of 74 |
June 4, 2005
a 2 MW turbine has a rotorspan of 80 meter.
windturbines need to be placed apart 5 times the rotorspan. so one 2 MW turbine needs an area of 400m x 400m. So 1 MW per 80.000 m^2 wich equals roughly 20 acres in those funny units you use in the states. |
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14 of 74 |
June 5, 2005
And I made it clear that I calculated the "puniness" of 72 TW because that is what the first comment to this article was expressing such awe about.
How are my calculations "atrocious"? (I did mistype the result, which should be 14.4 trillion, not billion, acres -- sorry!) 1.8 TW of load would require 562,500 square miles of wind plant (equal to a fifth of Australia). But of course you'd need much more than that to hope that somewhere there's enough wind to meet rises in demand above the average load, as well as thousands of miles of new transmission wires. Or massive new pumped hydro facilities to store production when it doesn't correspond to demand. And so on. |
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15 of 74 |
June 5, 2005
Rucio...
I'm terribly sorry to nitpick here, but you keep refering to 72 TW as the target installation, where the article makes clear that this is the size of the resource. The estimated load is only 1.8 TW. If the rest of your calculations were correct this would have made a big difference. But the rest of your calculations were atrocious, so it really didn't do anything but increase the amount of hyperbole on this site. |
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16 of 74 |
June 5, 2005
Who cares?
These are all minor details. While we argue people are dying in the middle east and China is investing heavily in oil and defense. America is on the decline and needs to get off oil in hurry. Here's renewable energy right where oil was in the early 1900's, everyone trying to figure out the details. % of the Earth needed to meet our needs by wind power? Chill guys. We've got a long ways to go... and just remember what the industrial revolution did to textiles, within a matter of a few decades it took one person to do the work of 200 before that. What renewables needs is some Howard Hughs/Rockefeller type that will charge with no reservations. We hippy hugging liberals need to quit bickering and buck up. |
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17 of 74 |
June 6, 2005
If it's clean air in which you're interested, each kWh of wind energy reduces the load on some conventional plant by a kWh. So, while not replacing entire plants, they are replacing output of those plants. Less emissions results.
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18 of 74 |
June 6, 2005
As others have made pretty clear, wind is considered a supplemental energy source. Current market and physical conditions have determined its' market position to be that way due primarily to the intermittent nature of wind. So, it doesn't tend to 'replace' anything, but allows use to continue to grow without adding to the CO problem. It's only in that sense it replaces them.
You could look at the Ultsira Project. If they weren't doing this (with wind), then they'd definitely need energy from somewhere. http://www.hydro.com/en/our_business/oil_energy/new_energy/hydrogen/winds_change.html It's coming....so once enough follow, it can actually begin to replace existing facilities. Probably, as they retire rather than outright subplanting. I can't point to it now, but I did see one study which claimed a wind installed base, combined with transportation restructuring, threshold by which intermitancy factors become negligable since at some point, there'd be wind somewhere at enough places to provide the minimum. That'd take some pretty snappy management if it even possible. But, I suppose at some point the installed base would need to be managed in such a way. |
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19 of 74 |
June 6, 2005
As I think I've made clear, my criticism of industrial wind is in fact precisely because I am interested in cleaner air, which is why I am dubious about the "sexed-up" claims epitomized by the hype around this Stanford map.
I ask again for the evidence that industrial wind has actually (not theoretically, or will have) closed down any "conventional" plant. |
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20 of 74 |
June 6, 2005
BTW, I know of only one 'field' type installation in the US (Altamont See: http://www.personal.dvint.com/events/windfarm2001/windfarm2001.html). Even it can be considered arrays of linear type installations (it's actually a test field with a lot of different types of turbines, not a designed integrated production facility)
All the others are of the liinear type. (often with two lines offset half a bay) The notion that linear farms are not practical is convoluted. Many of these are well in excess of 100MW farms. Some as large as 300MW. |
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21 of 74 |
June 6, 2005
rucio's math and viewpoints sounds alot like george (the puppet of big oil and coal) bush's wmd predictions in Iraq. To bad when wind-power is easing the effects of globing warming some numbers freak that cant count has to knock it. Oh talk about air-heads rucio should move next store to southren utility corps coal fired plants(the ones known to be the dirtiest in the country) and see what his view point about clean air is then.
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22 of 74 |
June 6, 2005
Did some quick calcs and need to revise that a little. Actual footprint area for a 5-acer/turbine optimised site would require about 30,000 SF per turbine, or about 3/4 acre.
This accounts for a 100' square pad around a 15' diameter tower and a 30 foot wide road for 660' to the next tower. |
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23 of 74 |
June 6, 2005
A sales professional with a major turbine manufacturer has said to me that turbine tower spacing can be as little as one rotor diameter (space between, thus 2x rotor diameter from tower to tower). I'm assuming this is for linear type installations and not 'field' types with rows and rows of turbines and wind area is needed from turbine to turbine.
So, for ground use, 5 acres is considered minimal, or about 2.5-acres/MW. That again would be for a linear installation. When one considers farmland uses of these areas, the actual reserved land used by the turbine footprint is only around 1/4 acre/tower, including access roads. |
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24 of 74 |
June 6, 2005
The acreage issue - most land under the turbine is useable - grow biomass!
http://www.illinoisrenew.org/docs/index.html New Wind Farm in Lee County The Mendota Hills Wind Farm generates clean power near Paw Paw, IL by Drs. Robert and Sonia Vogl There's a new wind farm in operation in rural Lee County just west of Paw Paw. It consists of 63 towers spread over a total of 2600 acres. Less than one half acre is used for each unit, including pad and crane. The total acreage consumed for the entire farm, including roads, is 31 of the 2600 acres. This leaves the remaining 2569 acres for farm land. Each tower is 207' from the ground to the center of the rotor . Each blade has a length of 81'. |
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25 of 74 |
June 6, 2005
As I said, the Dena study is biased in favor of industrial wind development yet recognizes that the goal could be achieved more cheaply.
And probably more effectively: How much conventional power has been closed down in Denmark because of wind power? |
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26 of 74 |
June 6, 2005
@Rucio
One more thing about the DENA study: Germany does not have a really great wind resource, in a lot of areas in the U.S. the windspeeds are much higher, improving the number considarably. @ Charles: you have been discussing with the wrong people. ;-). I can assure you anyone professionally involved in this issue is aware of the costs. But also that: * Current electricity production is also heavily subsidised. This year your president gave big handouts to nuclear and fossile fuel * Tax-payers pay to clean up the mess after nuclear and fossile fuel power production. This is not visible in you per kWh price. * There is no really free electricity market, nor is there a level playing field. |
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27 of 74 |
June 6, 2005
by the way: the study also gives explicit numbers on CO2 savings through wind energy.
By a second way, some other results of this study are: * At least up to 14% wind eelectricty no additional back-up is necessary. * 2000 MW of conventional power can be closed down due to windpower. * 14% windelectricity in 2015 will increase electricity for household with less than half a eurocent / kWh. For industry the rise will be less than 0.2 eurocents/kWh. This includes the costs for grid extension, balancing power etc. see: http://www.wind-energie.de/englischer-teil/topics/050224-PM_dena_englisch.pdf http://www.deutsche-energie-agentur.de/page/index.php?id=717&L=4 http://www.ewea.org/documents/0510_EWEA_BWE_VDMA_dena_briefing.pdf |
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28 of 74 |
June 6, 2005
@ Rucio
Some notes about the DENA study you (unknowingly?) refer to: *The time horizon is only ten years. *It assumes that fossile fuel prices remain stable or increase only very little. Many would say this is rather unrealistic. *it gives some price to the external costs of CO2-production, but ignores other external costs of energy production (www.externe.info) |
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29 of 74 |
June 6, 2005
Dutchy seems to have it 'right' here...(congratulations!). If we kkep polarizing and parochializing the renewables debate (e.g. which individual technology best meets the world's energy needs), we'll miss the whole point that mixing the most appropriate wind, hydro, solar, biomass, remaining fossil and other technologies for each locality, and increasing the use of renewables over time, is the best solution!
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30 of 74 |
June 6, 2005
Regarding cost, even Germany's energy agency, which believes wind power will help, admits that the goal of reducing emissions could be achieved a lot more cheaply. Considering that construction of wind plants would have trouble keeping up with just the continuing increase in demand, it is obvious that at best they could only slow an increase in the fraction of emissions that is due to electricity generation.
Industrial wind is a sideshow distracting us from tackling the real problems. (That is why the coal industry is promoting wind power in the U.S.) |
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31 of 74 |
June 6, 2005
Dutchy: You say, correctly, that 'the question is "can windenergy contribute significantly to reducing CO2 and other pollution from conventional plants (like mercury and fine dust) at an acceptable price?" If you study the subject you will know the answer is "yes".'
I have studied the subject and have not found any evidence to justify a "yes" answer, even without considering cost. Can you cite some data showing reduced emissions due to wind power? |
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32 of 74 |
June 6, 2005
The AWEA itself says a wind plant requires 60 acres per installed megawatt. Get the figures of any existing facility and divide the area by the nominal capacity. Then divide by the capacity factor to get the area used for actual output.
Yes, the AWEA insists that planting and grazing continues right up to the foundation, but the acreage has nonetheless been transformed to an industrial site. Turbines on ridgelines can use less space if they're lined up at a right angle to the prevailing wind, but single lines like that will never provide significant power (and the number of feasible sites is quite limited), so the bulk will be the 50 (or 60) acres/MW facilities in open areas. |
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33 of 74 |
June 6, 2005
Wave power is nice, but still in a very early stage of technology development. In the future it might be an interesting supplement to the energy mix, but currently the technology cannot contribute significantly.
Some people think that we have the luxury of choosing between different renewable energy technologies or between renewable energy and energy savings. But the situation is so urgent that we do not have this choice. We need to reduce greenhouse gasses, and we need to reduce them quick. By all means necessary! |
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34 of 74 |
June 6, 2005
The importance of the research is the following:
Many people think the resource of wind-energy is small. This research shows it isn't. You can discuss intermittency, price etc, if you want to. But these are seperate issues. Furthermore, the question is not "can we supply all of our energy needs with windenergy". The question is "can windenergy contribute significantly to reducing CO2 and other pollution from conventional plants (like mercury and fine dust) at an acceptable price?" If you study the subject you will know the answer is "yes". You in the States can afford to take some risks with the climate, but we live below sealevel here! |
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35 of 74 |
June 6, 2005
The current electricity system already has the need of quickly adjustable back-up:
Fossile fuel plants are out of service for 15% of the time. Furthermore coal and nuclear plants cannot adjust theri output to variable demand. Even if they were 100% reliable they always need to be supplemented by hydro or natural gasplants to respond to changes in demand. Experts agree that because of this existing back-up at least 20% of windelectricity is possible without having to build new back-up. |
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36 of 74 |
June 6, 2005
About costs:
windenergy in Europe currently (2003 numbers) costs 4 to 8 eurocents per kWh. Fossile is in the range 3 tot 5 eurocents/kWh. So at some places it is already competitive. (www.ewea.org, see the "wind energy the facts" part) Furthermore coal plants cause a damage to society of 3 to 10 eureocents per kWh (www.externe.info). You don't pay this in you electricity bill, but in other ways, for example via your health insurance. If you take this damage into account windenergy is already cost-effective. Furthermore, the cost of windenergy decreases 5% per year. Fossile fuels only become more expensive. |
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37 of 74 |
June 6, 2005
@ Rucio
Could you post links to where you got these acres per MW number? The 5 times rotorspan rule I used is common practice in the windenergy world. The high number you use surprises me |
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38 of 74 |
June 7, 2005
Thank you to everyone who has contributed to this thread: very informative. I would be interested seeing the actual results of the study.
I would like to suggest ignoring comments from individuals who raise "red herring" issues that don't contribute to a reasoned exchange of information. |
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39 of 74 |
June 7, 2005
I think 12m/s would make you a Class 8 or better. Class I would be almost anywhere (0-4.4m/s).
Good luck on the air density thing. After all, we are talking about pretty basic aerodynamics. The idea is to find the most common way to extract energy from wind, not colonize Mars. And, I'm trying to imagine even a helicopter delivering a nacelle to 2300m. Those factors make the 'potential' not quite as great as one may think. Might as well harness tonados and hurricanes |
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40 of 74 |
June 7, 2005
Interesting remarks... however I would encourage stanford to look into a much higher potential... for exmple class 1 winds in the andean spine! Our projects have class 1 wind environments at higher altitude (as high as 2300 mtrs) and we are looking at roughly 12m/s speed averages... close to grid connection.... the key issue is to reduce the air density impact on energy yield....
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41 of 74 |
June 7, 2005
I had assumed your confidence was based on something factual you had read that you could share with us.
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42 of 74 |
June 7, 2005
I typed "reduced conventional energy production" into www.Google.com and got 2,920,000 hits.
...tell me you're trying. |
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43 of 74 |
June 7, 2005
Where is the information -- showing a reduction of other energy sources due to wind-generated power -- that you refer to?
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44 of 74 |
June 7, 2005
I can only suggest you read more. There's lots out there.
Electricity at your outlet isn't a theory. |
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45 of 74 |
June 7, 2005
The Utsira project is an experiment (a very good one), and the statement that "each kWh of wind energy reduces the load on some conventional plant by a kWh" is a theoretical statement only.
Why does Denmark boast of 20% of their electricity produced by wind but doesn't also point to a corresponding reduction of production from other sources? Why does Hull in Massachusetts boast of reducing their electricity costs by 15% (I believe it is) because of a wind turbine but doesn't say how much less electricity they bought from other sources (i.e., it looks like they reduced their cost only by selling "green credits")? As the Utsira project suggests, the only place where wind power appears to be potentially useful is a small closed system where it can be stored. In a few places, larger installations could use pumped hydro to store power (although then the wind is displacing hydro, which rather defeats its alleged purpose). |
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46 of 74 |
June 8, 2005
Ma needs to recheck the facts.
The contrary is far more obvious, and proven. |
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47 of 74 |
June 8, 2005
Even if variability and predictability weren't a problem, at a million dollars and 50 acres per nominal MW, 4 times that per average output MW, and 2/3 of the time output well below that low average, industrial wind is obviously not going to take us where we need to go.
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48 of 74 |
June 8, 2005
What hasn't been acknowledge yet with regard to wind energy and reliability is that there IS a certain scale of predicability of wind.
Certainly, not the ability to be ON/OFF as a choice, but meteorologists do now daily predict wind for the following day. Weather system, time of day, region all affect availability and there is some anticipation. We can expect that particular attribute of weather forecasting to improve with time as well. |
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49 of 74 |
June 8, 2005
Actually, I'm in the same position as V. Pale, so I can't argue with you about the Dena report.
As for redundancy -- yes, there is extra capacity to cover the loss of a major plant, but wind plant doesn't provide that (since they can't be told when to provide power, let alone how much; they also need the power from the grid themselves to run). The redundancy of wind plant is instead meant to smooth out the fluctuations of wind-generated power, so it has to be over a huge geographic area, with the ridiculously large acreage requirements already discussed. And so they must metastasize in the attempt to behave like a reliable power source. Yet, as the blackout in Spain showed, and the large drops Eon Netz describes, it still doesn't work out too well. |
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50 of 74 |
June 8, 2005
I won't deny that there have been problems. Partially these have been caused by older wind turbines based on obsolete technology, partially by grid codes and regulations that are not made for windenergy. But the dena study shows that these problems are solvable with existing techniques and adaptation of grid codes and regulations.
The last few years there have been about six major black-outs in Europe. Only one had something to do with windenergy, moreover it could have been prevented with other grid regulations. |
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51 of 74 |
June 8, 2005
@ Rucio
Also returning to a point I made earlier: Every power source is to some level "unreliable" and needs redundant back-up. When a powerplant "trips" it's supply is lost within seconds. The contribution of a windpower plant to grid stability and reliability you keep ignoring the results of the dena study that don't fit your point of view. Maybe the most important result of the study is that integration of large amounts of wind energy into the grid is technically possible, and affordable. In Germany the cost of grid expension for windenergy is only 5% of the investments that need to be made anyhow. |
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52 of 74 |
June 8, 2005
I think you mean that the stability of the total wind-generated power increases as more wind plant is added (on the theory that if the wind isn't blowing here, it might be over there). Which goes back to a point I made earlier that to be useful it requires widespread redundant capacity (with a corresponding increase in high-voltage transmission lines. Even so, the whole thing can drop out quickly, as documented by Eon Netz and seen in recent blackouts in Spain.
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53 of 74 |
June 8, 2005
It appears the consensous is now that as wind energy increases, it actually _improves_ grid reliability due soley to the nature of distributed application.
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54 of 74 |
June 8, 2005
Language error:
in the above contribution read "net" as "grid" |
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55 of 74 |
June 8, 2005
@ Pale
I can read German and I can assure you that CO2 scrubbing and storage is not investigated in the dena-report. You should be aware that the leakage to Spiegel has been part of "spinning" by the net operators (who are vertically integrated, and thus also own the coal and nuclear plants). The delay in the publication had not so much to do with the content of the report, but with the summary. The original version was felt to be strongly biased. Despite some disagreement with the assumptions on the price development of fuel and CO2 certificates,renewable energy specialists the report generally regard the report as fairly positive. A lot of doomsday scenario's of wind opponents have been proven false by it. It shows that the large amounts of wind energy can be integrated into the net, without additional back-up and for relativley small costs. |
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56 of 74 |
June 8, 2005
I disagree with Ma's depiction of wind energy as not being the way to clean up our energy use.
In coming years, traditional power plants will look like dinasours and depict a time in our history when 'efficiency' was determined soley on the basis of ROI. Wind will contribute greatly to that. As for how utility cos are going to stay profitable when plants shut down, you only need to survey the industry. Utility companies are currently placing themselves at the forefront of renewable energy production. Around here, it's virtually impossible to develope a wind farm without first getting an RFP from a utility company. And, utility cos apparently own contract rights now on many, if not most, of the highest potential wind sites (those with wind AND proximity to a grid connection). What we have are utility cos contracting to other utility cos for wind farm development. It's already becoming a captive marketplace. IMO, the transportation restructuring is the thing while will allow real open market development. But, seems that process is being paced with utility cos efforts to capture markets in advance. My $0.02 |
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57 of 74 |
June 8, 2005
As Donald Rumsfeld has said for years now about Iraq, success is just around the corner!
How many more giant turbines will Denmark need to install to start showing a significant reduction in other power sources? It's like the mountain that groaned and gave birth to a mouse. Except it's rows of giant thundering machines where before was rural (relative) peace or wilderness. This is clearly not the way to clean up our energy use. |
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58 of 74 |
June 8, 2005
My knowledge of the Dena report, since I don't read German and the government is apparently not rushing to provide translations (as they had already delayed release of the report until Der Spiegel leaked it), is unfortunately only through British news reports, but I had read that it did directly compare the cost of installing scrubbers in existing coal plant smokestacks to remove CO2.
The Irish Grid published a study in February 2004 which made the same conclusion, that the goal of CO2 reduction could be achieved much more cheaply than by wind power. Interestingly, there's a story in today's New York Times about the Bush administration's alterations of climate change reports to increase doubt and downplay research findings. Appalling and frighteningly wrongheaded, to be sure, but Der Spiegel said that the Dena report was delayed for the same reason: to downplay negative findings against industrial wind. |
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59 of 74 |
June 8, 2005
@Rucio
about the closing down other plants due to wind: Sweden is closing down a big nuclear plant, it plans to replace it's output with wind electricity. Germany is phasing out of nuclear. Wind will (partially) replace this capacity. In general it is difficult to come up with this "hard proof" that you demand. electricty consumption has grown considerably over the last decade, and all electricity production goes on one big "stack". So the information is very diffuse and it is difficult to determine what is a consequence of what. By the way, it is funny that you are happy to (mis)quote the Dena study when it supports your case, but when it doesn't it is suddenly "just theory". Ever heared of cheryy picking? |
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60 of 74 |
June 8, 2005
One more note about the DENA study discussion.
They did not compare the CO2 avoidance costs from wind energy with that of other methods directly. They compared it with the costs of buying CO2 certificates. Such a certificate can be given out by somebody who produces less Co2 than his quota. The price for these certificates is an assumed one, many experts think it is too low. It would have been more interesting if the wind energy CO2 avoidance costs had been compared with the CO2 avoidance costs of coal power plants with CO2 storage. |
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61 of 74 |
June 8, 2005
I think that one reason that you dont hear about coventional power plants closing down are because the demand for the electricity keeps going up.
Simple question to all of you.. How are the utility companies going to stay profitable if they dont have new customers? They need at least a 2% continues growth rate year after year.... |
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62 of 74 |
June 9, 2005
The experiment has already been done: Denmark boasts 20% wind penetration. What is the record there for its displacement (let alone replacement) of other sources?
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63 of 74 |
June 9, 2005
IF I'm understanding what's going on here, it appears to me the debate centers on the extent of wind integration not just into the system, but rather, becoming much of the base system, which then would require back up generation to assure reliability.
The DENA study would appear to support it (though I've only read the summary/press releases since they're in English) based upon avalibility thresholds of mass installations. That remains debatable. But, it should not now be questioned whether wind energy contributes at all. That has been proven beyond any reasonable doubt. One sure way to find out is to try. As with everything from space exploration to vinyl siding, it'll take some tweeking to optimize. Certainly, the time to try would be when existing conventional plants can still produce. |
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64 of 74 |
June 9, 2005
So the reasonable characterization of wind power's contribution is valid only at low penetration (5-10%) in a small network. As demand continues to grow, even keeping that small penetration means even less contribution from wind (and greater costs for the rest of the system).
Because of this upper limit, the elusive savings promised by the wind could be much more effectively achieved by conservation and efficiency. And environmentalists could return to working to reduce and make cleaner all energy use rather than supporting the building of yet more power plants. |
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65 of 74 |
June 9, 2005
To Dutchy's summation that there is a small capacity credit for wind and that wind does displace other fuels:
The Irish Grid study of February 2004 (http://www.eirgrid.com/EirGridPortal/uploads/Publications/Wind%20Impact%20Study%20-%20main%20report.pdf -- 172-KB PDF) finds these effects rather mitigated, particularly as the penetration of wind plant increases. They found that with greater penetration the capacity credit quickly levels off. Similarly as excess nonwind capacity has to be added to cover the intermittency of the wind plant, the proportion relative to the wind capacity increases as more wind plant is added. That is, the addition of significant wind plant requires the building of equally significant excess nonwind plant. The study discusses the extra costs of running and maintaining this excess plant. They also found that as the system needs expanded the contribution of the same penetration of wind plant was further diminished. |
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66 of 74 |
June 9, 2005
I hope that I somehow can get through that you need an advanced statistical analysis to determine what is possible with windenergy as part of the production system. These studies have been done and show that more is possible than you think.
P.S. The EON report you refer to, does not give a thorough analysis. It just gives some carefully choosen examples, and fails to compare with conventional plants. |
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67 of 74 |
June 9, 2005
Let me try to help you with the concept.
Also a conventional back-up cannot be always relied upon, they are 15% of the time unavailble. A part of this unavailility is unexpected and sudden. So to get 100% reliable back-up you need a back-up for the back-up and a back-up for the backup, ad infinitum. That would be a bit expensive so instaed one settles for somewhat like a 99% reliability. Which reduces everything to statistics. Wind turbines deliver at least a part of their power for 75 to 85% of the time. So in a very simplisitic analysis you could say that they deserve a capacity credit for their minimum production. But there is more to it. It is not interesting be able to deliver electricty whenever. It is interesting to deliver electricity when there is a demand. It happens to be the case that in many climates there is a correlation between electricity demand and wind speed. This increases the so-called capacity credit of wind energy a bit further. |
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68 of 74 |
June 9, 2005
Rucio's request for that proof was ignored by "Guest User" and admitted to be problematic by Dutchy, whose examples of Sweden and German shutting down nuclear plants are only hopes that wind "will" be able to fill the gap. But surely the impact of Denmark's 20% wind penetration should be fairly obvious -- unless its impact is embarrassingly (particularly for Vestas, Denmark's 2nd largest company) small.
The facts that I have seen do not constitute proof that wind is achieving any of the industry's claims. They do not even suggest that it could, much less "will." But I guess it's more important to destroy what little unindustrialized landscape we have to show how much we care. |
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69 of 74 |
June 9, 2005
@ Rucio
I have the feeling we are running around in circles. And have some misunderstandings. Let me try to summarise my position. The contribution of 1000 MW of wind to the reliability is ofcourse smaller than of a 1000 MW gaspower plant. But it is not zero. Consequently 1000 MW of win power will not replace 1000 MW of conventional power, but approx. 100 to 200 MW of conventional power can be left out without changing the realibility of the system as a whole. The remaining 800 to 900 MW do not replace capacity, but they do save fuel. These are outcomes of scientific studies. |
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70 of 74 |
June 14, 2005
The 72 TW estimate is actually real deliverable power, not a capacity measure. To get total energy in a year, multiply it by 365*24 to get TWh. We too believe that the estimate is low. We are assuming that 13% of the land would be covered by 80-m tall 1.5 MW turbines at a density of 6 per square kilometer. All this info is in the paper, which should come out soon.
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71 of 74 |
June 15, 2005
In the Irish study the costs are based on costs of 2002, the fact that windenergy costs are dropping by 5% per year have not considered.
Again: the costs have not been compared with actual alternatives, but only with buying CO2 certificates. And again: we do not have the luxury of only "picking the low hanging fruit". We will need energy efficiency as well as renewable energy. |
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72 of 74 |
June 15, 2005
"As demand continues to grow, even keeping that small penetration means even less contribution from wind (and greater costs for the rest of the system)."
You must explain how you reach this conclusion. I cannot find this in the text. "excess nonwind capacity has to be added to cover the intermittency of the wind plant," This is at best a confusing line, at worst misleading. In the report all scenario's including wind energy have less conventional capacity than the scenario without wind energy. |
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73 of 74 |
June 15, 2005
@ Rucio
Nice that you finally accept the outcome of studies that are "just theory". Ofcourse is the capacity credit dependent on the penetration level. This is kicking in an open door. It should be noted that Ireland is a small island with only one limited capacity connection to the UK. (If I read it correctly this connection is not considerd in the study). For larger systems the capacity credit can be bigger, and the saturation point is reached at higher levels because windpark are distributed over a larger area and the larger amount of conventional plants allow more flexible operation. |
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74 of 74 |
June 16, 2005
Americans allways say they are the first, the biggest, etc. However, a year ago M. Hoogwijk got her PhD. on the same subject:
http://www.chem.uu.nl/nws/www/publica/e-2004-2.pdf |
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