Small Wind Turbines Towers [RE-wrenches]

[matthew tritt]

Jeff,

You're absolutely right on this, except there are a couple other issues that
need to be included in your equation, namely:

1. Bird kills. Guy wires are responsible for at least as many bird kills as
rotor blades, most probably many more. The wires become invisible to most
birds in heavy fog.

2. Vulnerability. Lose one guy and you lose the turbine.

3. Erection hazards. (I'll bite my tongue) Many small turbine accidents
occur during erection and/or lowering, some are crippling or even fatal. The
dangers increase the taller the tower if you're not using a crane.

4. Space requirements. The taller your tower, the more room is required on
the ground for the installation.
Sometimes you just don't have the luxury of all that accessible space.

5. Topographical limitations. In my part of the planet, the best winds are
usually in difficult terrain, namely ridge tops. Guyed towers are
inappropriate for narrow, steep ridges; you can't always install anchors on
the side of a cliff. A very tall tower is usually the only thing that will
work in a forested site, and that means guys, but that's some thing we don't
have to worry about here.

6. Aesthetics. Unless you're in love with erector sets and Corps of
Engineers bridges, most people don't like the looks of guyed towers. I've
heard this time and again over the past 20+ years.

7. Code restrictions. In case you didn't know, in many parts of California,
there are height restrictions for
turbine installations; in many cases 60' or less! This is a real drag. We
have a local ordinance restricting
siting to "non-critical view-shed" places, which limits tower height by
default.

There are other factors too. One of my customers tells me that he will
gladly put up with lower overall output just to avoid having a "monstrosity"
on his property. He was referring to a Rohn SSV with a 10 k Bergey, by the
way! This is why I prefer tapered monopoles, even if they are more expensive
initially.
They are clean, can be installed virtually anywhere and produce a reduced
hazard to our avian buddies.
Wind turbine siting is a very critical issue, which is why I talk most
potential wind customers out of expensive wind systems, but, in many cases,
a good hybrid system can off-set the lower overall output
of a turbine on a 40' or 50' tower.

Blast away!

Matt


----- Original Message -----
From: "Jeff Clearwater" <clrwater at earthlink.net>
To: <RE-wrenches at topica.com>
Sent: Friday, December 06, 2002 6:21 AM
Subject: Re: Small Wind Turbines Towers [RE-wrenches]


> Hey Mo,
>
> I'm with David on this one.  Wind is a such a wonderful and
> productive technology when 3 things happen:
>
> 1)  The resource is there (average wind speed) to justify the
> expense, aesthetic impact of the tower, installation hassle, and
> maintenance
> 2)  The tower is well engineered to the machine and the site and the
> tower IS TALL ENOUGH
> 3)  The customer understands this is not totally armchair technology
>
> With PV you have room for the "I want it really because I want to
> make a statement" kind of customers - even if the economics are
> marginal and they are not willing to do maintenance.  With wind, you
> want to really make sure it's the most appropriate match all the way
> around.
>
> So for your customer how about either:
>
> 1)  Talking straight with him.  Free standing towers are a major
> foundation engineering and installation effort compared to a tilt-up
> tower.  And as Mick S. used to say in his wind workshops.  The three
> most common mistakes in wind installations are insufficient tower
> height, insufficient  tower height and insufficient tower height.  To
> get high tower heights with free-standing towers you have to go with
> a pretty massive installation like the SSV series.  Go with a guyed
> tower and you reduce your expense, hassle and up your KWhrs cause you
> can go higher easier.
>
> 2)  OR convince him to install some monitoring equipment before going
> for the machine and take data for at least 6 months.  That way he
> keeps alive his vision, you buy some time to educate him more and
> perhaps the data will either convince him to let it go or convince
> you that it is really worth it on a KWH basis.  Data monitoring is
> really not that necessary in most wind installs if you can read the
> site, talk to the locals, talk to someone who has put one in locally
> etc.  But if the resource availability is questionable and/or the
> technology/customer match is questionable, then it can be a good way
> to slow down the process until it shakes out a bit.
>
> Why can't he accept a guyed tower?  The hinged guyed towers are a
> snap to install compared to a free-standing SSV (especially when you
> get up to the 80-100' that is usually smart to go to) - especially
> below 2KW.  There's a whole lot of value in tension members (guys)
> vs. massive materials/foundations and lots of steel.
>
> So there's my .02 from the little I know of your situation.  What I
> do know is the wind installs I've done are a whole lot more energy
> overall than any PV install could ever be.  The liability issues,
> engineering, customer relations - all have to be tighter.  If you
> haven't done some wind, I'd start with a nice tilt-up tower kit
> engineered for a specific machine installed on a for-sure windy site.
>
> Best,
>
> Jeff
>
>
> >Mo,
> >
> >Unless the customer lives on a high flat butte with no tree's or
> >buildings, I would strongly encourage you to push him to a taller
> >tower.  Tower height is no place to cut corners...small wind systems
> >are challenged enough as it is to meet customer expectations.  It's
> >hard for me to imagine why if he's willing to be spendy on a
> >free-standing tower, he'd want to install something as small as the
> >XL1.  The economics of this would go from bad to horrible.  By the
> >way, Bergey does sell free-standing Rohn SSV and Monopole towers.
> >It wouldn't be hard to build a tower-top adapter for the XL1.
> >
> >Just my $0.02
> >
> >David
> >
> >At 11:02 AM 12/5/2002, you wrote:
> >>Hi All,
> >>
> >>I have a potential customer who is interested in a Bergey XL.1.
However, he
> >>requires a 50'+ tower and will only accept a guy-less type.  Bergey has
not
> >>been very responsive so far.
> >>
> >>Any suggestions?
> >>
> >>Thanks,
> >>Mo
> >>--
> >>Mo Rousso
> >>HelioPower
> >>Renewable Energy Systems
> >>Remote Power Solutions
> >>mrousso at heliopower
> >>www.heliopower.com
> >>760.845.8843
> >>
> >
> >----------------------------------------------------------
> >David Blecker, P.E., Director
> >Seventh Generation Energy Systems
> >608-424-1870 (ph)  424-1810 (fax)
> >
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>
> --
> ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
> Jeff Clearwater
> Ecovillage Design Associates - Whole Systems Design
> Community and Village Scale Renewable Energy & Water Systems
>
> Cell: 720-480-8455
> Office:  800-440-2523 (PIN-7071)
> Fax:  720-528-7813
> jeffc at ic.org
>
> Council Member - Ecovillage Network of the Americas -
http://www.ecovillage.org
> Advisory Board - Living Routes - Ecovillage Education -
> http://www.livingroutes.org
> Founder:  Ecovillage Research, Development, and Demonstration Program:
> http://www.home.earthlink.net/~clrwater/RDD/rdd.html
> ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
>
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>
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>
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>

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