It’s damning, and published by a green group. The study cited by the BBC is from the John Muir trust of all places. This would be a good place to point out what I posted a few days ago: The reality of wind turbines in California. Told ya so. From the BBC:
BBC story here (h/t to WUWT reader Wayne)
James Delingpole quips that “Official: wind farms are totally useless” Well, maybe not totally useless (unless he’s talking about the ones in Hawaii from my recent article) but these efficiencies are proof positive that the current wind power technology will never be anything but a small sporadic supplemental power source.
PRINCIPAL FINDINGS
in respect of analysis of electricity generation from all the U.K. windfarms which are metered by National Grid, November 2008 to December 2010. The following five statements are common assertions made by both the wind industry and Government representatives and agencies. This Report examines those assertions.
1. “Wind turbines will generate on average 30% of their rated capacity over a year.”
2. “The wind is always blowing somewhere.”
3. “Periods of widespread low wind are infrequent.”
4. “The probability of very low wind output coinciding with peak electricity demand is slight.”
5. “Pumped storage hydro can fill the generation gap during prolonged low wind periods.”
This analysis uses publicly available data for a 26 month period between November 2008 and December 2010 and the facts in respect of the above assertions are:
1. Average output from wind was 27.18% of metered capacity in 2009, 21.14% in 2010, and 24.08% between November 2008 and December 2010 inclusive.
2. There were 124 separate occasions from November 2008 till December 2010 when total generation from the windfarms metered by National Grid was less than 20MW. (Average capacity over the period was in excess of 1600MW).
3. The average frequency and duration of a low wind event of 20MW or less between November 2008 and December 2010 was once every 6.38 days for a period of 4.93 hours.
4. At each of the four highest peak demands of 2010 wind output was low being respectively 4.72%, 5.51%, 2.59% and 2.51% of capacity at peak demand.
5. The entire pumped storage hydro capacity in the UK can provide up to 2788MW for only 5 hours then it drops to 1060MW, and finally runs out of water after 22 hours.
OTHER FINDINGS have emerged in the course of this analysis in addition to the Principal Findings which related to the testing of five common assertions. These Other Findings are listed below.
1. During the study period, wind generation was:
* below 20% of capacity more than half the time;
* below 10% of capacity over one third of the time;
* below 2.5% capacity for the equivalent of one day in twelve;
* below 1.25% capacity for the equivalent of just under one day a month.
The discovery that for one third of the time wind output was less than 10% of capacity, and often significantly less than 10%, was an unexpected result of the analysis.
2. Among the 124 days on which generation fell below 20MW were 51 days when generation was 10MW or less. In some ways this is an unimportant statistic because with 20MW or less output the contribution from wind is effectively zero, and a few MW less is neither here nor there. But the very existence of these events and their frequency – on average almost once every 15 days for a period of 4.35 hours – indicates that a major reassessment of the capacity credit of wind power is required.
3. Very low wind events are not confined to periods of high pressure in winter. They can occur at any time of the year.
4. The incidence of high wind and low demand can occur at any time of year. As connected wind capacity increases there will come a point when no more thermal plant can be constrained off to accommodate wind power. In the illustrated 30GW connected wind capacity model with “must-run” thermal generation assumed to be 10GW, this scenario occurs 78 times, or 3 times a month on average. This indicates the requirement for a major reassessment of how much wind capacity can be tolerated by the Grid.
5. The frequency of changes in output of 100MW or more over a five minute period was surprising. There is more work to be done to determine a pattern, but during March 2011, immediately prior to publication of this report, there were six instances of a five minute rise in output in excess of 100MW, the highest being 166MW, and five instances of a five minute drop in output in excess of 100MW, the highest being 148MW. This indicates the requirement for a re-assessment of the potential for increased wind capacity to simulate the instantaneous loss (or gain) of a large thermal plant.
6. The volatility of wind was underlined in the closing days of March 2011 as this Report was being finalised.
* At 3.00am on Monday 28th March, the entire output from 3226MW capacity was 9MW
* At 11.40am on Thursday 31st March, wind output was 2618MW, the highest recorded to date
* The average output from wind in March 2011 was 22.04%
* Output from wind in March 2011 was 10% of capacity or less for 30.78% of the time.
The nature of wind output has been obscured by reliance on “average output” figures. Analysis of hard data from National Grid shows that wind behaves in a quite different manner from that suggested by study of average output derived from the Renewable Obligation Certificates (ROCs) record, or from wind speed records which in themselves are averaged. It is clear from this analysis that wind cannot be relied upon to provide any significant level of generation at any defined time in the future. There is an urgent need to re-evaluate the implications of reliance on wind for any significant proportion of our energy requirement.
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The variability alone is enough to kill the idea, IMO. 5 min of outage (or, for that matter, large surge of output) is not just an inconvenience: it’s fatal to the Grid, not to mention many of the users.
Bogosity squared.
Pretty much what I discovered here in Ontario. ontariowindperformace.wordpress.com
When will a study be done like this in the US?
This comment from the BBC article may not have been noted yet:
‘However, Jenny Hogan, director of policy for Scottish Renewables, said no form of electricity worked at 100% capacity, 100% of the time.
She said: “Yet again the John Muir Trust has commissioned an anti-wind farm campaigner to produce a report about UK onshore wind energy output.
“It could be argued the trust is acting irresponsibly given their expertise lies in protecting our wild lands and yet they seem to be going to great lengths to undermine renewable energy which is widely recognised as one of the biggest solutions to tackling climate change – the single biggest threat to our natural heritage.
“We have yet to hear the trust bring forward a viable alternative to lower emissions and meet our growing demand for safe, secure energy.”‘
Yes, it could be argued that they are acting irresponsibly, if you think that saying the Emperor has no clothes is irresponsible . . .
vboring says:
April 6, 2011 at 12:09 pm…..
An electric generation magazine (Power Mag) recently discussed their top 5 energy storage options. It sounds like 80% round trip efficiency storing electrical energy at a utility scale is becoming practical. Also, technologies to fix CO2 into liquid carbon fuels are on the list.
http://www.powermag.com/issues/features/Energy-Storage-Enables-Just-in-Time-Generation_3556.html
Thanks for the reference. It’s either brown outs, lots of energy storage, or spinning fossil fuel plants as the % of variable renewables come on line.
The DOE, as noted in Power, is going to fund some new hydro storage-
http://www.powermag.com/POWERnews/3594.html?hq_e=el&hq_m=2171943&hq_l=11&hq_v=bb09315ba5
For your visual pleasure – Germany, denmark, spain, ireland unajusted hourly wind production data 2009
http://www.theoildrum.com/files/GDSI_combined_raw_wind.png
G. Karst says:
April 6, 2011 at 7:14 pm
Hydrogen is easily bottled.
===================
We were told that if we only hooked up all these wind farms to the grid, we would be able to generate electric power from this renewable source. It would be expensive, yes, but worth the price.
Now someone comes along, and says, well actually, you also need to buy all this extra stuff at huge cost, because the wind farms can’t power the grid. You need to make hydrogen and bottle it. I say, this wasn’t the deal. This is the classic bait and switch scam. Get the customer to fork out for a system that doesn’t do what was claimed, and then get them to invest even more. Simply to save sunk costs, the poor customer is left to hand over still more dough to the scamsters. I say, on yer bike!
From Luís on April 7, 2011 at 12:54 am:
Barge-gate, where after a “hacker” releases the real electricity generation info for the offshore turbines, it’s noticed some are supplying 24/7 at times when the winds had been calm for days, and it’s discovered their locations are being used as grid access points for electricity supplied by small Chinese modular nuclear plants stationed on barges (thus technically not on UK soil thus not needing regulator approval and ducking public approval).
Wait for it…
old engineer says:
April 6, 2011 at 11:25 pm
I certainly won’t argue with an old engineer. They know what they are talking about.
Hydrogen in it’s ionized state are merely swimming protons. They can migrate through all containments. H2 is much better, but still extremely problematic. I agree, natural gas can transport in a hydrogen designed system, but hydrogen cannot transport in a natural gas designed system.
During my various careers, I have witnessed about a dozen accidental H2 detonations. I was inside one of them (completely unscathed). Old style, on-line gas chromatography instrumentation was a constant hazard.
Having said that, I have also witnessed Circuit Breakers explode, Air Compressors heads explode, Coal mills and pulverizers explode. If one has been around long enough, one gets to see almost everything explode. Energy extraction is a hazardous enterprise, no matter the method.
I think we are all in agreement, that the present utilization of wind power is badly implemented. Point of use generation is it’s main virtue, and this is completely nullified under the present model. If one has to transmit windmill product, either gas or electrical, it’s viability, disappears. Without a storage capability, it is not even viable as point of use.
As a old engineer myself, I abhor, the possibility of discarding the baby, with the bathwater. We have wind power already, lets make sure it contributes effectively, by finding it’s proper niche, performing a task more suited to it’s characteristics. GK
Vince Causey:
I hear you loud and clear. I too, feel cheated. What can we do? GK
If UK politicians were so keen on windpower, I would expect to see one of the massive new turbines due to be installed in the London Array (mouth of the Thames actually), installed on College Green outside the Houses of Parliament (where all the interviews by the media are done).
Cat in hell’s chance..? Why, exactly..??
Nearly every company or corporation will do trial studies before launching into some new effort. It is just economically unfeasible to go into anything without good justification. I get the feeling that, as far as wind power is concerned, there were no trial studies. Nobody set up a device to measure and record the wind speed for over a year in anyplace where they put windmills. I think someone just drove out somewhere, got out of the car, and said “Gee, the wind is blowing here right now. Good place to put some windmills.” I probably put more thought into where I plant my strawberries.
Pumped storage hydro is a funny one too… Because the second law of thermodynamics makes it particularly unattractive.
As the pumps used to lift the water up into the reservoir are say 80% efficient (possible with new, large pumps), and the turbines are 80% efficient (possible), then the combined energy efficiency of the system is 64%. Which means 36% of the “energy” you produced is lost as low grade heat. That makes a lot of sense.
Janice:
In your post at April 7, 2011 at 2:03 pm you say;
“I get the feeling that, as far as wind power is concerned, there were no trial studies. Nobody set up a device to measure and record the wind speed for over a year in any place where they put windmills.”
Sorry, but your “feeling” is mistaken. They did do wind measurements but not the right ones.
This is addressed in the Muir Report and it is why many commentators in this thread have mentioned that using averages is an error.
Importantly, the effect of strong winds is often overlooked. Wind turbines operate when the wind is strong enough and not too strong. People understand that no wind means no power, but many do not know that high wind means the wind turbines are furled so they then provide no power.
This need to provide no power in high winds derives from two factors: i.e.
the power of the wind increases as the cube of the wind speed
and
the tip speed of a wind turbine must not go supersonic.
A wind turbine starts to provide power when the wind starts to blow strong enough . Then, as the windspeed increases the turbine’s blades are partly furled so they extract a lesser proportion of the available power. The degree of furling is increased as the wind speed increases until the blades are completely furled and the turbine ceases to provide power.
A large safety factor is needed for when the turbine will stop providing power at high wind speeds. This is because at high wind speed a gust of slightly higher wind speed has a lot more power. This large amount of extra power from a slightly higher wind speed is because the power of the wind is proportional to the cube of the wind speed.
If you are not technically minded then you can jump over the next bit and go down to ***.
Wind is the movement of air. Perpendicular to the wind direction, the wind’s kinetic energy per unit time (ek) is provided by the mass (m) and the square of the velocity (v) of the air with density (ρ) moving through a unit area (A).
ek = ½ m v^2 = ½ (A v ρ) v^2 = ½ A ρ v^3
***
If the turbine were not furled then as the wind speed increased the turbine would spin faster and collect more energy from the wind. But the speed of the tips of the turbine’s blades increases as the turbine spins faster.
And, importantly, at high wind speed a small gust is a lot of extra power (because ek is proportional to v^3). So, a small gust would spin the turbine much faster. And this must not be allowed to happen.
Wind turbines are big. They do not need to spin at a high rate for the tips of their blades to be moving very fast. And if the speed of those tips breaks the sound barrier the resulting stresses on the blades would destroy the turbine (failures of this kind have happened).
So, a turbine operates when the wind is sufficiently strong but not too strong. This provides a range of wind speeds in which a wind turbine operates. And the proportion of time the wind stays in that range during a year defines the output of the turbine (assuming no downtime for maintenance).
The proportion of time that the wind is above a certain level and the average wind speed do not provide the relevant information: i.e. they do not indicate the proportion of time that the wind speed is within the range of wind speeds at which the turbine can operate.
I hope this is helpful and explains the matter with sufficient clarity.
Richard
Taliesyn:
Re your comment at April 7, 2011 at 4:10 pm, pumped storeage does make a lot of sense.
The need for power stations to operate is reduced by use of ‘pumped storage’. Electricity is used to pump water uphill to a reservoir when there is little demand from the grid. Then, when there is peak demand for electricity the water is allowed to flow back down and generate power. As you say, this consumes electricity because of mechanical losses, but it is economic because it removes the need for a few power stations to operate almost continuously on standby mode so they can supply electricity at the (very short) times of peak demand. The pumped storage provides the extra electricity needed to meet the peak demand.
Conventional (i.e. thermal) power stations fission a material or burn a fuel to obtain heat that is used to boil water and to superheat the resulting steam which is fed to the steam turbines (some power stations – e.g. combined cycle gas turbine: CCGT – also use gas turbines in combination with steam turbines). The turbines drive turbogenerators that make electricity.
A thermal power station takes days to start producing electricity from a cold start. Time is needed to boil the water, to superheat the steam, to warm all the components of the power station, and to spin the turbogenerators up to operating speed. Anybody who has boiled a kettle knows that will take time, and a power station takes days to start up.
So, ‘pumped storage’ throws away generated power, but that power would have been thrown away anyway because each thermal power station is designed to provide an output of electricity. It can only provide very little more or very little less than this output (i.e. a power station has a “low turndown ratio”).
The energy that would have been thrown away during times of low electricity demand is used to pump the water of the ‘pumped storeage’ system. Thus, ‘pumped storage’ reduces the need for a few power stations to operate almost continuously on standby mode so they can supply electricity at times of peak demand.
Richard
G. Karst says:
April 7, 2011 at 9:08 am
…Hydrogen in it’s ionized state are merely swimming protons. They can migrate through all containments. H2 is much better, but still extremely problematic. I agree, natural gas can transport in a hydrogen designed system, but hydrogen cannot transport in a natural gas designed system.
—-
H2 is still a big problem. It’s just not practical to store significant quantities of H2 for significant amounts of time. Unless someone comes up with the super-hydromatic storage system we’re never going to be running our cars or planes on H2, excepting some baffling drones. Fix it into ammonia? Maybe. Some have suggested using that as the true storage medium. A chemist would have to comment on the practicality of that.
Electrolysis also has efficiency problems. 25% was a number that stuck in my head but simple googling suggests maybe it’s 50%. Still not great.
Nope, the best way to store vast quantities of (electrical) energy remains pumped hydro, which is reasonably efficient, but you can only pump so much water…
Many of life’s ironies are controlled by a small number of pieces of crucial information. In the case of wind farms not meeting the expected percentage of generation capacity as promoted by the political classes usually comes from the sad fact of the politicians failure to understand that an average is not a real thing but a wholly artificial construct. Because most politicians have not yet grasped that an average is not a real thing, they cannot understand that averages derived from real measurements can lead us to believe other stuff that is not real.
By working out the average of wind flows in a particular place being assessed for the suitability of wind turbines, the statisticians have made their first huge mistake – average wind speed does not exist in reality and is therefore irrelevant. What matters is the frequency with which the wind blows at the speeds that can be used to safely rotate a turbine. Any other measurements are merely a trip into the realms of unreality and this has caused wind farms to be such a failure. The wind flow over turbine blades is rather similar to the three plates of porridge Goldilocks found; only one plate of porridge was ‘just right’ for her. Erecting wind farms in locations which have high average wind flows is pointless. Erecting a wind turbine on a site where the wind usually arrives at gale force is as pointless as erecting one in an area where the wind rarely blows at all.
Another interesting fact about averages that most politicians seem unable to understand is that half of any population must be, by definition, below average on any measure; the other half of that population must be, by definition, above average on the same measure. Which is why the spectacle of politicians calling for the raising of the ‘average performance’ of students taking a specific annual examination in the state schools they control, as an example, is so sad. And they do it constantly.
Very little wind today where I live in the UK – calm at ground level and about 10mph at 2000 ft. I noticed the local wind farm (who doesn’t have a local wind farm these days?) weren’t turning for a while. Just then, one – only one – of the turbines began to turn. I strongly suspect this is one of those examples of the turbine drawing power from the grid to make it turn for engineering reasons.
I kept seeing the long amortization periods and tried to imagine how these devices would last longer than a roofing tile without periodic upkeep .. which costs more.