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Shetland windfarm - Viking Energy


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Regarding the last three posts:

 

1) - Egbert-Mcwhirter, on 23 Oct 2013 - 6:38 PM

 

Thank-you kindly for your approval - but I 'do' engineering, not politics. To expand: What I do is not 'what is it called?', but 'what does it do, and how does it work in practical terms?'

 

Unfortunately Philip you didn't "do" enough of the engineering. Taking the average wind speed against the turbine output at that speed is pretty much pointless.

 

Take a look at:

http://www.wind-power-program.com/wind_statistics.htm

http://www.wind-power-program.com/mean_power_calculation.htm

 

This gives a detailed overview of how to calculate the power output. It's interesting stuff.

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What's confusing me is the fact that VE refer to a 53% load factor for Burradale - Load Factor being the ratio of actual output over a period of time, to peak load (demand). You are talking about Capacity Factor which is, as you say, the ratio of actual output over a period of time, to maximum possible output.

 

Misleading isn't it?

 

 

I would say confusing rather than misleading, and going back to the VE website, it's not exactly clear what they are talking about. They start off talking about capacity factor, then load-capacity factor and finish with load factor. I have e-mailed them asking for clarification.

 

I'll post the answer here when (if) I get it.

 

 

That will be interesting.

 

I also think Philip Andrews raises some very interesting points about wind speed (Lang Kames anemometer data) and turbine power curves. Looking at Burradale for evidence is interesting but not the right way persuade investors or the public that the VE project is going to be sufficiently productive.  A very small negative difference in efficiency will have huge financial implications.

 

 

The problem with Philip Andrews letter was that he took the average northern hemisphere windspeed and tried to use that to demonstrate that windfarms won't work in Shetland, which is quite clearly nonsensical. The windspeed here is way above the average for the entire hemisphere. If he had used the average windspeed from the observatory outside Lerwick, then he might have had a point. But then I doubt the resulting figures would have supported his argument.

 

Anyway, I got a reply from VE about the load factor/capacity factor thing.

 

The 53% figure quoted for Burradale is (as I always assumed), capacity factor. Here's the relevant bit from the e-mail:

 

 

 

Regarding the load factor/capacity factor confusion, you’re probably aware (and possibly annoyed) that the two terms are sometimes used as if they were interchangeable as a measure of the average power output over a period of time. The load factor definition you refer to is more associated with traditional power stations, although this is not an area I have any expertise in.  

 

I suspect you already know the answer to your question: the 53% referred to for Burradale was its average capacity factor at the time. I understand it is still always over 50% in the course of a year and it retains the world record for the highest recorded capacity factor for an onshore wind farm (57.9% during 2005).

 

Apparently VE are going to be up-dating their website within the next couple of weeks so hopefully things like this will be made a little clearer.

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The 53% figure quoted for Burradale is (as I always assumed), capacity factor. Here's the relevant bit from the e-mail:

 

 

 

Regarding the load factor/capacity factor confusion, you’re probably aware (and possibly annoyed) that the two terms are sometimes used as if they were interchangeable as a measure of the average power output over a period of time. The load factor definition you refer to is more associated with traditional power stations, although this is not an area I have any expertise in.  

 

I suspect you already know the answer to your question: the 53% referred to for Burradale was its average capacity factor at the time. I understand it is still always over 50% in the course of a year and it retains the world record for the highest recorded capacity factor for an onshore wind farm (57.9% during 2005).

 

Apparently VE are going to be up-dating their website within the next couple of weeks so hopefully things like this will be made a little clearer.

 

 

Thank you for liaising with VE on this issue and getting them to rectify their site.

 

Burradale Windfarm Phase 1 - A (Capacity (kW): 1,980.00)

 

Sep 2012 to Aug 2013 Average Capacity Factors = 43.90%

 

Burradale Wind Farm Phase 2 -A (Capacity (kW): 1,700.00)

 

Sep 2012 to Aug 2013 Average Capacity Factors = 47.80%

 

Link: http://www.variablepitch.co.uk (The capacity figure shown is from Ofgem)

 

The overall average capacity factor of Burradale for Sep 2012 to Aug 2013 is 45.7%.

 

Viking Energy claim it to be 53% on average using their load factor/ capacity factor interchangeable terminology.

 

I hope they clear up a bit more than just these definitions up when they update their website. 53% average at the time, "always over 50%"!!! Well lets see the evidence that backs up these figures on their website. I'm happy to be corrected.

 

Loss on transmission comes next as a deduction (best not quote figures from the VE website). I'm thinking (finger in the air) they end up with 30-35% at best, NOT 53%

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on the trump issue theantis need to think carefully that they don't get involved with trump. he is not a nice guy.

I do so agree with this.  Not Donald Trump, please not.  He is a twunt.

 

 

As far as I understand it, SS are not involved with Trump.  Trump has a legal dispute too with the Scottish Government.  I don't know the ins and outs of Scottish law, but in England another party could join proceedings even if the other party objected - it saves Court costs and time.  The same would probably, I imagine, happen under the Scottish legal system.  So whilst SS might not like it, if Trump decides to join the legal action, it isn't Trump and SS pulling together but more a legal terminology in a sense.  SS can object to the Court and the Court can ignore them and join Trump in the action.

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The 53% figure quoted for Burradale is (as I always assumed), capacity factor. Here's the relevant bit from the e-mail:

 

 

 

Regarding the load factor/capacity factor confusion, you’re probably aware (and possibly annoyed) that the two terms are sometimes used as if they were interchangeable as a measure of the average power output over a period of time. The load factor definition you refer to is more associated with traditional power stations, although this is not an area I have any expertise in.  

 

I suspect you already know the answer to your question: the 53% referred to for Burradale was its average capacity factor at the time. I understand it is still always over 50% in the course of a year and it retains the world record for the highest recorded capacity factor for an onshore wind farm (57.9% during 2005).

 

Apparently VE are going to be up-dating their website within the next couple of weeks so hopefully things like this will be made a little clearer.

 

 

Thank you for liaising with VE on this issue and getting them to rectify their site.

 

Burradale Windfarm Phase 1 - A (Capacity (kW): 1,980.00)

 

Sep 2012 to Aug 2013 Average Capacity Factors = 43.90%

 

Burradale Wind Farm Phase 2 -A (Capacity (kW): 1,700.00)

 

Sep 2012 to Aug 2013 Average Capacity Factors = 47.80%

 

Link: http://www.variablepitch.co.uk (The capacity figure shown is from Ofgem)

 

The overall average capacity factor of Burradale for Sep 2012 to Aug 2013 is 45.7%.

 

Viking Energy claim it to be 53% on average using their load factor/ capacity factor interchangeable terminology.

 

I hope they clear up a bit more than just these definitions up when they update their website. 53% average at the time, "always over 50%"!!! Well lets see the evidence that backs up these figures on their website. I'm happy to be corrected.

 

Loss on transmission comes next as a deduction (best not quote figures from the VE website). I'm thinking (finger in the air) they end up with 30-35% at best, NOT 53%

 

 

The 53% figure is the average for the entire first 10 years of Burradales operation. and also I know that over the last couple of years they have had down time associated with gearbox replacement and they also removed the blades from all of the turbines for maintenance which, again, would have involved extra downtime, so I expect that would explain those lower figures.

 

Why don't you e-mail them to find out?

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