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Forum Index : Windmills : How to calculate the annual (kWh) output

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Wes Lemarr
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Joined: 07/09/2008
Location: United States
Posts: 35

Posted: 01:47pm 24 Aug 2011

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Hi Guys
I found this chart on the internet, do you think that this is a reasonably accrete indicator of the output of a wind generator? Thanks
Wes LeMarr

Tinker

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Joined: 07/11/2007
Location: Australia
Posts: 1904

Posted: 01:58pm 24 Aug 2011

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Maybe, if the wind blows very consistently 24/365. It rarely does

Klaus

Wes Lemarr
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Joined: 07/09/2008
Location: United States
Posts: 35

Posted: 02:16pm 24 Aug 2011

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Klaus,

Hear is another http://www.reuk.co.uk/Calculate-kWh-Generated-by-Wind-Turbin e.htm
This Calculator takes the "Weibull Shape Parameter" in to consideration, maybe it is more accurate?

Wes

Wes Lemarr
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Joined: 07/09/2008
Location: United States
Posts: 35

Posted: 03:12pm 24 Aug 2011

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Sorry bad link.
http://www.reuk.co.uk/Calculate-kWh-Generated-by-Wind-Turbin

e.htm
Thear should not be a space between "Turbin" & the "e" in the link above.
Edited by Wes Lemarr 2011-08-26

Gizmo

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Joined: 05/06/2004
Location: Australia
Posts: 5111

Posted: 12:00am 25 Aug 2011

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http://www.reuk.co.uk/Calculate-kWh-Generated-by-Wind-Turbin e.htm

The top table is not much use. We dont know the turbine efficiency or alternator efficiency. Is the wind speed a average? I would ignore it.

The link is better, but unless you know the values to enter, its also not much use either. What is the turbine/alternator efficiency?

The only way to get a figure is through testing in real conditions. Measure the power output at different wind speeds, and make your own table of data with the values. Then record windspeed for a few days/weeks to build up a table of average windspeed data.

Unfortunately many small commercial wind turbines are overrated by the manufacturer, based on a couple of simple tests performed on the bench. Too often we hear of someone who bought a turbine rated at say, 300 watts, but after spending their money and investing time putting the turbine up on a mast, they find they average 50 watts, and only see 300 watts during a storm, just before it failed!

This has lead to a general misstrust of the small wind turbine industry. There are good turbines out there, but only because the manufacturer has invested a lot of time into their reliability and provide realistic figures.

Glenn

The best time to plant a tree was twenty years ago, the second best time is right now.
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