I need help, it would be possible?

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I need help, it would be possible?

Postby Maru » Wed Feb 26, 2014 9:33 am

Hello, all be with you: I hope so.
I have a question, do not actually know to solve this issue, or am I not hitting oscalculos do, but let's ask the question:
When the electric power can be generated is equal to the rated power of the wind system obtained, the capacity factor will be equal to:
I thought these four variables,
5
10
1
0.8
3.2
So I think I'm missing somewhere, have no formula to arrive at a real value, these values ​​through a variety of formulating what I was passsado in other forums, but that did not result in a satisfactory level yet.
Appreciate the help of Lords to resolve this impasse.
From already thank you for any help you have given me.
graciously
Marcelo :?:
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Re: I need help, it would be possible?

Postby Gordon-Loomberah » Wed Feb 26, 2014 11:12 am

Hi Marcelo, welcome to the Energy Matters Forums :)

I'm not sure I understand your question, but the capacity factor of wind farms generally runs in the 30-50% range.
IE, a 40MW wind farm operating at a 50% capacity factor will be, on average producing 20MW, and produce 480MWh/day.
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Re: I need help, it would be possible?

Postby Helipos » Thu Feb 27, 2014 9:44 am

Hi Marcelo, I once saw the gearly generation graph of a particular windfarm. Damn windy place, while i dont have the actual capacity factor I can remember the average output power was only 30% of the windfarms capacity.

Without a lot of data on wind speed, time of day, directions, et cetera. There is no pratical hope in calculating the capacity factor, as it is influenced by generating capacity, demand for the generated power and power system constraints in transporting the power.

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Re: I need help, it would be possible?

Postby Gordon-Loomberah » Sat Mar 01, 2014 2:33 pm

Here is an article about the capacity factors of some Australian wind farms:
http://reneweconomy.com.au/2014/agl-ene ... city-90242
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Re: I need help, it would be possible?

Postby Maru » Sun Mar 02, 2014 6:45 am

I thank everyone who has responded to my inquiry, but what I really need is a formula or calculation to arrive at an efficient outcome.
they do not know how to get to an effective and correct.
someone would have a way to calculate this coefficient?
they do not know which formula to use? to be honest I have no formula to make this calculation.
So how to answer this question, I have only the values​​, but do not know how to reach them.
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Re: I need help, it would be possible?

Postby Gordon-Loomberah » Sun Mar 02, 2014 9:42 am

If you want to do it on an annual basis the formula would be:

Actual output in kWh for the year/Rated output of wind generator in kW * 24 * 365

So for a 250kW WTG that produced 1GWh for the year, the capacity factor would be:

1000000/250 * 24 * 365 = 45.7%

Some of the wind farms in South Australia operate around this sort of capacity factor or a bit better.
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Re: I need help, it would be possible?

Postby Smurf1976 » Wed Mar 05, 2014 9:45 pm

What are you actually trying to work out?

For a large grid-connected wind farm, capacity factor over a 12 month period is generally the most useful piece of data since it directly influences the economics of the whole project. At present, grid constraints limiting wind farm output are not common (they happen, but not to a great extent) such that they can (and usually do) sell everything they can produce. Hence the relevant question is annual output versus the cost of building and operating it - it's a financial question primarily.

On the other hand, for an off grid system it's a very different consideration. It's not much use having a 33% capacity factor if that comes about via 4 months of running flat out and 8 months sitting idle. Whilst that's a ridiculously extreme example, in such a case you're seriously limited in terms of the usefulness of that power. You'll have far too much for 4 months, then nothing for 8 months. You may well have a 33% capacity factor but it's of very limited use as a stand alone power supply if there's a huge seasonal variation.

In an off-grid system, the minimum output levels over a much shorter time period, a week or two, are generally a much more relevant consideration assuming battery storage.

For example, if you know (based on proper data) that you can have up to 10 days with effectively no wind generation, but will always be fairly close to the long term average if measured over 20 days, then it's fairly straightforward to design a system that will work under those conditions and provide reliable power at all times. But you need to know the severity, duration and frequency of the "gaps" in generation to be able to work this out - a simple annual capacity factor doesn't tell you that.

It's much the same with solar, and as an example where I work we have a large number of small stand alone solar systems at remote locations. Based on proper data, we know that up to 12 consecutive days of minimal solar generation is a credible scenario that will happen from time to time but that longer periods are extremely infrequent (15 days of low generation being a 1 in 20 year event). So, for both financial and technical reasons, we've designed based on this actual data knowing that, based on historical records, it will work.

The exact same principles are used in the design of large scale hydro systems by the way. It all comes down to knowing the quantity and frequency of inflows then designing everything else based around that. The turbines need to be big enough to use the available water, but not too big otherwise that's a waste of money. The dam wall needs to be able to withstand a worst case flood and so on - but you first need to work out how much water a major flood actually involves in order to design the dam to cope with it. It all comes down to a huge amount of maths from an engineering perspective, then looking at the financial aspects - there's no point doubling the cost of the scheme in order to get an extra 2% of power produced during the occasional flood, it makes more sense to just let the flood go over the dam and generate power from the other 98% of water that's reasonably reliable and predictable.

Unless you really are trying to power something in space etc, this stuff is generally a question of both engineering (technical) and finances with a compromise between the two. It needs to be safe and it needs to work, but there's also usually a desire to keep the costs down.
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Re: I need help, it would be possible?

Postby Maru » Thu Mar 06, 2014 12:30 am

Sure, you're right, came very handy your comment, because for me I'm starting, and studying hard to learn more about it, because here in Brazil we have no current literature on the subject oo little knowledge is retained in ~ s hands of a few.
Thank you for your cooperation and reports concerning my subject matter in this forum.
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