"Wind power myths are blown away"

[Iterate]

I ran across this blog on Greenpeace UK and thought it might be of interest. The UK is also painfully coming to grips its energy usage, its native resources, and its own path forward.

If you've ever tried to convince people down the pub about wind power and how it can help steer us away from climate catastrophe, you'll be familiar with the arguments used to dismiss it. The technology is too expensive; electricity bills will rocket; and (one that's often tripped me up) what happens when the wind stops blowing and the lights go out?

If that's the case, then for your next pub discussion arm yourself with a new study by energy analyst David Milborrow which successfully trounces all those claims and more. A joint commission by Greenpeace, WWF, RSPB and Friends of the Earth, it's being launched in advance of the government's renewable energy strategy that is expected next week.

So what does it say? First of all, that old chestnut about the wind dropping and the lights going out is just not true. Of course, the wind does fluctuate, but averaged out across the country that fluctuation is much less. (The UK is, of course, the windiest country in Europe.) This means that while the output from one wind farm might dip as the wind subsides, the wind will still be blowing somewhere else, and the larger the nationwide network of wind farms, the smaller the variations in electricity generation.

In fact, research by Oxford University's Environmental Change Unit shows that low speed wind events affecting 90 per cent of the country only happen for, on average, one hour every year (pdf).

More:http://www.greenpeace.org.uk/blog/climate/wind-power-myths-are-blown-away-20090709
The study mentioned here is at:http://www.greenpeace.org.uk/media/reports/wind-power-managing-variability

[imdjh]

1. I still think that if we get all these windmills, the earth will slow down and we will fall off. nt

[zbdent]

2. what does it say when they get to "Ted Kennedy voted agaisnt it!"

(claiming that he opposed it due to "aesthetic" reasons ...)

(I know it's not a myth, but that's the usual talking point)

but never mentioning that Ted Stevens also voted against it ... why no outrage there?

[Berry Cool]

4. My response would be

"Well, I guess if you were a fabulously wealthy politician with a gorgeous view from one of your homes that few people on the planet could ever dream of affording, and you were afraid of what it might look like with some clean white turbines added to it, and you thought your right to a gorgeous view trumped other people's right to a source of electrical power, you would vote against it too."

Personally I don't think turbines look so bad. I don't know why they upset some people so.

Edit: Too bad this didn't address the other favorite oppositions to turbines, namely that they are horribly noisy (not from what I have observed) and that they kill gazillions of birds and bats (which they don't--I mean, for crying out loud, from the way people talk, you'd think the blades turned as fast as, say, helicopter blades...and those REALLY whir, but I have yet to hear anyone argue that helicopters should be banned because they kill birds and bats).

[Ready4Change]

13. I like their looks. Older models did killl birds, but not newer, larger ones.

I think windmills are beautiful, and larger ones are graceful. My wife thinks they should be painted to look like flowers. I like them clean, white and spacey.

The older models for large installations spun too fast and did kill birds. Now large fields of windmills use larger models, whose blades spin a LOT slower. They don't kill birds, and the taller towers and blades reach higher, steadier winds.

I've wondered about the smaller turbines meant for single home use, and birds. They spin fast, so I'd think they'd be a risk. Any one have info on that?

[The Croquist]

3. One hour a year.

That's is a surprising statistic. In a relatively small country such as the UK that is good news.

[phantom power]

5. The geographic redundancy solution does incur some costs.

For one, it assumes an electric grid that can actually accomplish that kind of balancing across a wide geographic area. For another, it also assumes around a 5x "overbuild" of wind turbines.

I've been trying to find a paper that OKItsJustMe posted a while ago, that was a really great data-mining study on geographic redundancy, where they showed an empiric curve that related effective capacity factor against overbuild. Their curve showed that you can obtain an effective 90% capacity factor (equivalent to a baseload coal or nuke plant) at about 5x overbuild, combined with geographic dispersal.

[kristopher]

6. You may be looking for this

SUPPLYING BASELOAD POWER AND
REDUCING TRANSMISSION REQUIREMENTS
BY INTERCONNECTING WIND FARMS


Cristina L. Archer* and Mark Z. Jacobson
Department of Civil and Environmental Engineering
Stanford University, Stanford, California
5 February 2007
ACCEPTED FOR PUBLICATION IN
JOURNAL OF APPLIED METEOROLOGY AND CLIMATE

Abstract
Wind is the world’s fastest growing electric energy source. Because it is intermittent,
though, wind is not used to supply baseload electric power today. Interconnecting wind
farms through the transmission grid is a simple and effective way of reducing deliverable
wind power swings caused by wind intermittency. As more farms are interconnected in an
array, wind speed correlation among sites decreases and so does the probability that all
sites experience the same wind regime at the same time. Consequently, the array behaves
more and more similarly to a single farm with steady wind speed and thus steady
deliverable wind power.
In this study, benefits of interconnecting wind farms were evaluated for 19 sites,
located in the Midwestern United States, with annual average wind speeds at 80 m above
ground, the hub height of modern wind turbines, greater than 6.9 m/s (class 3 or greater).
It was found that an average of 33% and a maximum of 47% of yearly-averaged
wind power from interconnected farms can be used as reliable, baseload electric power.
Equally significant, interconnecting multiple wind farms to a common point, then
connecting that point to a far-away city can allow the long-distance portion of
transmission capacity to be reduced, for example, by 20% with only a 1.6% loss of
energy.

Although most parameters, such as intermittency, improved less than linearly as the
number of interconnected sites increased, no saturation of the benefits was found. Thus,
the benefits of interconnection continue to increase with more and more interconnected
sites.


And this is also important:

Emissions and Energy Efficiency
Assessment of Baseload Wind
Energy Systems
P A U L D E N H O L M *
1500 Engineering Drive, University of WisconsinsMadison,
Madison, Wisconsin 53706
G E R A L D L . K U L C I N S K I
439 Engineering Research Building, 1500 Engineering Drive,
University of WisconsinsMadison, Madison, Wisconsin 53706
T R A C E Y H O L L O W A Y
Center for Sustainability and the Global Environment (SAGE),
1710 University Avenue, University of WisconsinsMadison,
Madison, Wisconsin 53726

Abstract
The combination of wind energy generation and energy storage can produce a source of electricity that is functionally equivalent to a baseload coal or nuclear power plant. A model was developed to assess the technical and environmental performance of baseload wind energy systems using compressed air energy storage. The analysis examined several systems that could be operated in the midwestern United States under a variety of operating conditions. The systems can produce substantially more energy than is required from fossil or other primary sources to construct and operate them. By operation at a capacity factor of 80%, each evaluated system achieves an effective primary energy efficiency of at least five times greater than the most efficient fossil combustion technology, with greenhouse gas emission rates less than 20% of the least emitting fossil technology currently available. Life cycle emission rates of NOX and SO2 are also significantly lower than fossil-based systems.

[phantom power]

7. Yes, it was the first one! Here's a link to pdf:

http://www.stanford.edu/group/efmh/winds/aj07_jamc.pdf

Strange, I just re-did my calculations, and now I get an overbuild of 6.7x, for 87.5% capacity factor. Oh well, it's in that ballpark of around 5x.

[kristopher]

8. That's an unusual way to look at it.

It presumes you want to duplicate a number that is very relevant now, but wont be as relevant in a grid designed to integrate a variety of renewable sources. By that I mean the way efficiency, nuclear, solar, wind, and storage work to meet demand is much different than the way coal, gas and nuclear work together to meet demand. In point of fact once the renewable grid starts to take shape you won't be looking for a "baseload" wind plant so much.

If we graph our image of the current grid in operation we would see one line for generation and one line for consumption that (hopefully) track each other nearly perfectly.

If we perform the same mental exercise with a renewable grid, we have a more complex visual where generation, delivery and consumption would each have a line.

[phantom power]

9. It's true, a comprehensive picture will be more complicated...

However, my personal take on "the future" is that people will still want to think in terms like "Hey, our economy is growing(*), we need to add another gigawatt of capacity to our grid."

So, let's suppose you want to add a gigawatt of capacity to your grid, and you want to do it by building some geographically dispersed wind turbines, and you'd like your new gigawatt to have a 90% capacity factor. I still assume that when somebody wants to add capacity, they want it to be reliable capacity, and a 90% capacity factor seems to be a pretty common level of reliability that people design around.

What the paper suggests is that to do the above, I would expect to build around 5 gigawatts worth of wind turbines (0r 6.7, or whatever), geographically dispersed, to add that capacity.

Clearly, that hypothetical scenario ignores the possibility of applying storage facilities. It also doesn't take into account mixing sources, like wind/solar, etc. But I still think it's a useful thought experiment, just to get an intuition about what wind can do with geographic dispersal as the primary means of increasing reliability.



(*) I'm such an optimist.

[kristopher]

11. I agree with you... That's why I disagree

I agree people do/will want to think of it like that. That's why I have a slight aversion to thinking of it like that. As you say, the real picture is more complex. It is also *different* than the image nearly everyone holds of what is and is not desirable in an electric grid. For example, this perspective of baseload wind as a tool for evaluating how much capacity to add really doesn't give you much information for planning if, in fact, it doesn't represent reality.

Aside from that matter of preference in the way to view the data there is another point in that study worth noting. The authors used wind data averaged down into one hour readings for the analysis. Another study (I can't recall which one) used the same basic method as it relates to altitude and wind speed, and compared it against a more detailed minute by minute measured wind data. Since the power derived has a cube function in the formula, it is to be expected that an hourly average will understate the actual power produced since the process of averaging doesn't capture the cube on the high side.

The results of the comparison? The 1 hour average yielded a capacity factor of 33% while the minute by minute resulted in a CF of 44%. (this was for offshore)

I think if you're interested in planning, the Denholm article is actually the better of the two. It should be supplanted soon by the real world testing being done at that new integrated dispersed wind/CAES plant out in (?)Iowa(?).

[lindisfarne]

10. Denmark gets 20% of its electricity from wind power. Not at all impossible. n/t

[intheflow]

12. The two excuses I most often hear are

1) wind turbines kill birds. (Maybe... but at a higher rate than, say, jet engines or clear glass windows or hurricanes? Probably not.)

and

2) wind turbines will wreck our view. x(