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An analysis of 3000 wind turbines in the United Kingdom and Denmark shows the average lifespans of the turbines are significantly shorter than originally predicted, and that the capacity factor (aka load factor) greatly declines over a turbine's life.

http://www.telegraph.co.uk/earth/energy/windpower/9770837/Wi...

The analysis of almost 3,000 onshore wind turbines — the biggest study of its kind —warns that they will continue to generate electricity effectively for just 12 to 15 years.

[The usual lifespans quoted by the manufacturers are 20 to 25 years.- Pete]

Also from the Telegraph-
The report’s author, Prof Gordon Hughes, an economist at Edinburgh University and a former energy adviser to the World Bank, discovered that the "load factor" — the efficiency rating of a turbine based on the percentage of electricity it actually produces compared with its theoretical maximum — is reduced from 24 per cent in the first 12 months of operation to just 11 per cent after 15 years.

The decline in the output of offshore wind farms, based on a study of Danish wind farms, appears even more dramatic. The load factor for turbines built on platforms in the sea is reduced from 39 per cent to 15 per cent after 10 years.


More information here, including a pdf link to the full report.
http://www.ref.org.uk/publications/280-analysis-of-wind-farm...

The new nuclear power plants are designed to last 60 years, and the existing plants have already demonstrated the ability to operate past 40 years. With a lifespan of 12 to 15 years, they would need to replace the wind turbines three or more times.

- Pete
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That is useful information, but the logical follow-up is missing. Why is performance declining over time?

We know that delamination of the composite blades was a problem with early models, especially the ones supplied from India. GE claims to use an improved formulation. That problem should now be resolved.

If the mechanics of the turbines are wearing out, or lubrication or bearings are failing, those are issues that can be addressed.

We need the rest of the story.
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If the mechanics of the turbines are wearing out, or lubrication or bearings are failing, those are issues that can be addressed.
We need the rest of the story.

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Here is an article that addresses the O&M costs associated with wind turbines.

http://www.windpowermonthly.com/article/1010136/Breaking-dow...

There is a chart that shows the types and frequencies of the failure modes that can occur on the machines. (Delamination of the blades is not mentioned, nor is any problem associated with the blades.)

In terms of Incidents per 10 Machine Years, the following is the breakdown of the failure mechanisms listed:
Electrics- 5.51
Control Unit- 3.71
Sensors- 2.8
Hydraulics- 2.7
Yaw System- 2.5
Brakes- 2.0
Gearbox- 1.3
Generator- 1.3
Structure- 1.2
Drive Train- 1.0

As shown in the graphic, it is also important to consider the length of downtime for each failure. A gearbox failure, for instance, usually results in more downtime than an electrical component problem.

As time goes on, it would not surprise me if the wind turbines improve their performance. Failures are analyzed, and improvements are made in the next generation machine to reduce or eliminate the failures. This is how engineering is done. However, the machines still sit out in the open elements 365 days per year. Some failure modes might only be able to be controlled instead of eliminated completely.

- Pete
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Agreed. The data are for first generation designs. In time they should work their way down the learning curve. It takes a while, especially when you are asking for long term reliability.
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There is also no comparison of the downtime requirements of any other form of power. Steam Boilers ALL have to do some form of maintenance on the tubes, which is a different process in a Nuke from a Fossil Fueled boiler due to the tubes being exposed to combustion gases in the latter, but in all cases the boiler water/steam chemistry has to be carefully watched and the tubes de-scaled periodically AFAIK.

In other words, there is a hidden bias in this article, or some of the assumptions, as conventional plants (and Nukes) ARE designed with spare capacity to be able to back each other up for the scheduled maintenance.

Moreover, the power factors being listed are starting from the viewpoint of the Wind Turbine's upper limit (per the wind availability)... and so they look more fragile... I am not saying the tech is anywhere near the development completion/robustness of the conventional plants but I am a bit concerned at the way the comparisons are being done.
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"Lifespan of wind farms"

Shouldn't the title be:

Lifespan of wind turbines

Trees die; the forest doesn't.

I agree that longevity will improve with experience. Alternative if costs decline sufficiently, one can just plan on replacement every ten to fifteen years. Bolting a new turbine to an established base can probably be done in a day.

http://www.abelenergy.co.uk/wind-turbine-faqs

Peter
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Bolting a new turbine to an established base can probably be done in a day.
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At a cost, yes. GE, Vestas and the other turbine manufacturers still charge for their products. (GE managers love to sell wind turbines, because then they also get to sell a natural gas burning power plant to provide the majority of the power needed.)

The post below from the Energy Collective shows if the real capacity factors and wind turbine lifespans are put into the cost calculations, the cost of a wind farm in Vermont will be 28.3 cents per kilowatt-hour unsubsidized (18.9 cents/kwh subsidized) instead of the 10 cents/kwh originally promised to Vermonters.

http://theenergycollective.com/willem-post/61309/lowell-moun...

- Pete
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Electrics- 5.51
Control Unit- 3.71
Sensors- 2.8
Hydraulics- 2.7
Yaw System- 2.5
Brakes- 2.0
Gearbox- 1.3
Generator- 1.3
Structure- 1.2
Drive Train- 1.0

...
As time goes on, it would not surprise me if the wind turbines improve their performance. ...
This is how engineering is done.


Some of these, once the failure rate is known are easy to fix. For example, the sensors. The cheapest solution might be to just install an alternate backup set of sensors, then only shutdown and repair when two like ones have gone out. Of course maybe the sensors can be improved, but we'd need to know why they are failing. It can be as simple as dust and dirt covers an optical sensor.

On the structural problems. Structures are very well known. But to be economical they are going to design right at the margin. They can make every structure 10% better and eliminate 95% of the problems...but then the initial costs go up.

All the same cost tradeoffs go into steam plants as well. Things like condensate pumps fail. So they have pre-installed backups...probably sometimes with autostart features when they sense low pressure output.

It seems that, by design, wind farms already have pre-installed backups. Dozens or hundreds of other wind turbines, each one operating independently. The only "critical" components are where all the power is switched into the grid. So it is a big cost tradeoff of cost vs reliability and longevity.

Mike
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Most places I've lived lately have been over 20 cents per KWH
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Most places I've lived lately have been over 20 cents per KWH
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Year to date, through November of last year, the overall average price of retail electricity in the US was 9.88 cents/kwh. The US average residential price was 11.91 cents. For Vermont, the residential price was 17.25 cents, which is near the high for the 48 contiguous states.

http://www.eia.gov/electricity/monthly/epm_table_grapher.cfm...

- Pete
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Many nuclear plants have died before they reached their 40th birthday for various reasons:

Zion 1 & 2
Main Yankee
Trojan
Fort St. Vrain
Rancho Seco
Crystal River
Kewaunee

More nuclear plants that will probably die before reaching their 40th birthday:

San Onofre 2 & 3
Fort Calhoun
Indian Point 2 & 3
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