Wind Maps for California [RE-wrenches]

[David Blittersdorf]

Matt,

FAA lighting is required on 200' or higher towers unless near airports. We do alot of 
towers on ridgelines. For the wind energy industry we have sold almost 10,000 
measurement masts, most 30 meters or higher. Our best selling tower is a 50m with our 
new 60m gaining fast. 

The new wind maps done by NREL ( National RTenewable Energy Lab) or TrueWind 
are wind people and are doing things correctly. 

David Blittersdorf

On 18 Dec 2002 at 10:28, matthew tritt wrote:

> Bob-O,
> 
> True enough. For a real laugh, take a look at the wind data accumulating
> sensors at most airports. They are generally mounted on a building with
> about 6 or 8 feet of space between the roof, or wall, and the sensor.
> 10 meters from the ground yes, 10 meters from the effective ground no. 10
> meters is the nationally accepted sensor height for most ground-based
> meteorological stations but, on the water, they are generally mounted much
> closer to the surface on buoys. This is especially strange as, you will
> notice from the maps, most of our wind resource in Cal. is right along the
> coast.
> 
> Since the observed winds are often calculated at a point very close to the
> surface, there is a very good chance that the actual, useable winds are
> considerably greater than published. Using the "1/7th rule" to calculate
> winds at greater heights gives a reasonably accurate picture of the power
> available at those heights; I'm just too thick to make the formula work for me
> most of the time.
> 
> Another curious thing is the way in which anemometers are often mounted on
> poles. There is a 10 meter PG&E weather monitor tower near here (put there
> to calculate which way the radioactivity will travel during an "Event" at
> Diablo Canyon) with the cups mounted on the down-wind side of the tower. All the
> data gathered for our prevailing Westerlies is, therefore, hopelessly flawed
> because of down-wind turbulence (not to mention being located 15 feet from a
> highway!).
> 
> In spite of greater efficiencies of very tall towers, many ridge-top sites
> are not suitable for their use, because of installation problems and FAA
> height restrictions. Don't totally discount the appropriateness of shorter
> towers in certain applications. In some cases they are the only solution
> available and may be a very good choice. (IMHO)
> 
> Matt
> ----- Original Message -----
> From: "Bob-O Schultze, Electron Connection" <econnect at snowcrest.net>
> To: <RE-wrenches at topica.com>
> Sent: Wednesday, December 18, 2002 8:41 AM
> Subject: Re: Wind Maps for California [RE-wrenches]
> 
> 
> > Amigos,
> > IMO, the whole program of taking wind data readings from a 10m tower
> > and extrapolating it for higher (but not actually recorded) tower
> > heights is hopelessly flawed.
> > As David points out, there is still some turbulence at 10m even where
> > the measurement site is ideally situated. In reality, the data sites
> > are rarely so situated. I can show y'all pictures of all five of the
> > wind data sites here in Siskiyou county. One, maybe two give
> > semi-accurate data. the others are in the trees, right next to the
> > freeway where turbulence from trucks affect them, on and on. If your
> > 10m data is flawed, then any mathematical extrapolation from that
> > data is bogus. Garbage in, garbage out.
> > Bob-O
> >
> > >Yes, the wind increases with height above the ground. These are
> > >estimates of the
> > >windspeeds based on the assumed wind shear that is expected. I
> > >consider 30m to be
> > >the minimum height for good wind energy. Wind turbines mounted at
> > >10m generally do
> > >not work and if they do have very low energy production and much
> > >shorter life due to
> > >turbulence.
> >
> > --
> > Bob-O Schultze, Electron Connection
> > PO Box 203, Hornbrook, CA 96044
> > 800.945.7587 or 530.475.3402
> > fax 530-475-3401
> > www.electronconnection.com
> >
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> 

David Blittersdorf
NRG Systems, Inc.
110 Commerce Street
Hinesburg, VT 05461 USA
Tel: 802-482-2255
Fax: 802-482-2272
email: davidb at nrgsystems.com
Web:http://www.nrgsystems.com

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