To aid others: the link to "brazillions of windmills"
http://www.dailykos.com/story/2008/12/28/185825/42/388/677953 in the post I'm responding to ends at a hysterical rant typical of the poster's contributions here. In addition we also learn that this "author" found a report on Danish wind turbines showing:
all installed turbines,
when they came online,
their production capacity,
their rotor size and
their actual production data by year.
It is a valuable source of information if used properly and can be downloaded here:
http://www.ens.dk/sw34512.asp at these links:
Wind turbine master data as at end of November 2008 (data from 19 December 2008)
Wind turbine master data incl. links as at end of August 2007
Review tables and graphs as at the end of November 2008 (data from 22 December 2008) The data is sorted into two groups, decommissioned turbines and existing turbines. Working from the first link above (these are only the link labels, plz go to ens.dk site to download) the "author" of the "analysis" has followed this process:
"Microsoft Excel provides a YEAR function that converts numerical date strings into integer years that can be used in numerical calculations.
I have used this function to extract the lifetime for every decommissioned windmill, all 1,927 of them.
I have then used this data and the Excel MEAN function - not to be mean but to make a serious point - to determine what the mean lifetime of decomissioned Danish windmills is. It is 15.9 years, carrying one insignificant figure, or 15 years and 10 months.
I have used the MEDIAN function to determine that half of the windmills lasted less than 16 years and that half lasted more than 16 years.
I have used the MAX function to determine that the longest surviving windmill lasted for 28 years.
There was only ONE windmill that lasted 28 years, the 22 kW unit manufactured by Kongsted described on Row 188 of the spreadsheet for decommissioned units."
From this so called "analysis" these claims emerge :
"I think it is great that our fine President-elect has committed to building infrastructure - because this infrastructure is a gift to generations we have only saddled with the terrible consequences of our self-absorbed desire to maintain our car CULTure suburban lives.
Thus it matters what the life time and utility of that infrastructure is. Sixteen years does not qualify.
Here in New Jersey, we have the Oyster Creek Nuclear reactor, which came on line in 1969 and operates perfectly well. This reactor was a gift from my father's generation to mine.
Angry, vicious, malicious and ill informed people are trying to vandalize and destroy this New Jersey nuclear infracture that has already lasted and served for longer than any windmill in Denmark and could serve for decades to come with proper maintainence."
I refer to this as a "so called analysis" because it really fails to achieve the most basic function of an analysis - that is, an attempt to determine what is actually happening without prejudice or bias. The unseemly rush to judgment has ended at the conclusion that a 16 year life span is the typical physical limit of performance that can be expected of modern wind turbine technology. Unfortunately the data derived from this exercise does not provide a rational basis for this claim.
What it DOES tell us is this:
1) Between 28 years ago and today, 1927 turbines were installed and decommissioned.
2) The mean
time in service of these turbines was 15 years 10 months.
That is it. Nothing more. There is nothing provided to explain the circumstances behind the time in service data.
There is absolutely no basis for concluding that these turbines had reached any sort of mechanical limit to their functionality. In fact, elsewhere in the data is strong evidence that the decommissionings were not motivated by a limit to their functionality. I'll explain in a moment.
There is absolutely no basis for concluding that these turbines are in any way representative of the state of current technology or that conclusions drawn from their decommissioning is at all relevant to understanding the performance or failure to perform of current generation technology. None. In fact, elsewhere in the data is strong evidence that these turbines are, in fact, definitely NOT representative of, and cannot be used to predict, the performance or failure to perform of current technology.
The data starts in 1977 and runs through the end of 2008. That coincides, of course, with the site selection and placement of turbines as they have evolved from small deca-kilowatt units on short towers with small diameter rotors, to the large multi-megawatt units on 260 foot towers with 340 foot diameter rotors that are current generation technology.
If you go to the third link you'll find charts detailing the rate of installation by production and number of turbines, and another dealing with decommissioning. These charts make clear that at the time of the Kyoto Protocol (1997) there was a large increase in activity to commission and decommission wind turbines. The nearly 2000 small turbines that were taken off-line were replaced with larger, more productive units on larger towers. We know that these small turbines were 1) sited early and can infer with reasonable confidence 2) they were therefore logically occupying the areas with superior wind regimes.
A rule of thumb for spacing wind turbines is they should be placed about 5 rotor distances apart for correct wind flow. This means that fewer larger, more productive turbines replaced many smaller, less productive turbines, and in fact the data on rotor size and production capacity verifies this conclusion. The data tables and charts also confirm that a steady, nearly uninterrupted increase in both production capacity and number of installed turbines even though nearly all of the 2000 decommissioned turbines were accomplished within a relatively short time frame.
Now I will engage in some speculation that I believe is warranted.
If you were to investigate the market where small used turbines are bought and sold, you can (or could have) picked up a nice, used, fully functioning 20-75KW Danish turbine for a pretty good price.Now, it is evident that the "author" of this analysis went to a great deal of trouble to obtain and present erroneous and misleading information to the readers of this and other forums.
It is equally evident that the "author" of this "analysis" has the intelligence and knowledge to review the data and place it in the proper context as I have done. So please, ask your self why wasn't this done. Then go to the link under "brazillions of windmills" in his post and read the screed with that question in mind.
http://www.dailykos.com/story/2008/12/28/185825/42/388/677953