[Homestead] Solar and wind

Bill Jones billj at harborside.com
Thu Feb 8 16:33:08 EST 2007


EarthNSky wrote:

>I can't really read the key.  I tried blowing it up, but I lose 
>resolution...can anyone help?
>
>Bev
>
>  
>
I'm pleased to see that we're in category 4.

The information is in two columns.  Within each column, there are 4 
sub-columns, representing (L to R) the category number, power in 
watts/meter^2, speed in meters/second, and speed in mph.  It's not clear 
how the two columns differ.  The only heading is a distance in meters.  
I think that may represent the height off the the ground where they're 
measuring the wind.

Isn't it impressive that there's almost 1000 watts per square meter in a 
mere 20 mph wind?  The square meter in question represents the area of 
the rotor face.  This is yet another reason why I'm skeptical: the trend 
toward small rotors.  They seem to be trying to make people buy into the 
idea that their modern gadgetry will work so much better that you can 
now make do with an itty-bitty rotor.  Wrong!

Notice that it's actually a map of average power, averaged over the 
year.  During winter wind storms we get the greatest amount of wind 
power.  When the wind blows at 80 mph, there's 64,000 watts per square 
meter, enough to tear it apart!

So I think that's why our numbers seem a little overly impressive to 
me.  These outliers, the most extreme winds, have all been calculated 
into the average, even though these speeds were reached during a time of 
year when wise folks often shut down their windmills, and when the least 
water is needed.

Bill
S. Oregon coast




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