[RE-wrenches] Skystream tower heights

[Ross Taylor]

Hi Dan, Ian, and the others;

Your points are valid and, Ian, thank goodness we offer a tower for your
hypothetical "living under the tundra" situation.  :-)

In seriousness, I'm new to RE-Wrenches and I joined in response to one
recent inquiry which was forwarded to me outside the list (that Sunforce
question).  As a new member, and a rep for a manufacturer, I am trying to
tread lightly and respect the requests of the list moderator by not being
seen as promoting our product or clogging the list.  So, I'll back out
after this and will continue to monitor and respond to specific questions
about our products.  The tower height question and issue is valid, but I'll
let you wage that internally.  But let me leave a few parting thoughts:

1) Despite working for one manufacturer, I've installed and worked on
several brands and I am with you all in wanting to meet the customer's end
needs and expectations.  I'm also disgusted by the poor installations I've
seen.  I, too, have a good installation/bad installation presentation and
there are lots of ours in both groups. And I know some members of this
group have received some terrible installations photos of Skystream systems
which I've sent them. I want to promote good installations, not crummy ones.

2) I'll respectfully suggest (and then duck!) that "the 30 foot rule" is a
guide and is no more universally valid than "the 20 foot rule".  If both
cases, it implies an if-then certainty which doesn't take into account the
variety of site conditions.  Any who have attended my class will know that
I discuss this and show that they're a useful guide, but there are lots of
locations where a "60 foot rule" would be better.  If you're looking at
turbulence extending maybe 2X the height of an object and that object is
50-60 feet tall, then 30 feet may not be enough. I'm trying to teach proper
site evaluation, not "use this tower or this rule."

3) We offer a 34-foot tower because, in some locations, it provides a good
cost of energy solution.  But, and this is a big and clear but, it is NOT a
good option in any but some flat, uninterrupted, wide open areas.  Those
areas do exist, however, with enough frequency that our dealers demanded it
as an option.  In any but those isolated cases, though, a taller tower is
required.

4) We offer towers up to 70 feet in height.  That's not just monopole
towers - we have guyed towers as well.  So, even from us, nobody's stuck
with a monopole in a situation where a guyed tower is better.  And, to
clarify/correct a statement made, our warranty is NOT conditioned upon
using our towers.  We are trying prevent installations on under-engineered
towers which aren't designed to take into account dynamic forces of a wind
turbine.  We've seen failures of towers which were sourced cheaply and
which were not designed to support a wind turbine.  But, any dealer is free
to buy a turbine from us and a 120-foot guyed lattice tower of their
choice. The "up to 70 foot" tower limitation is just the limit of towers we
sell ourselves, at least now.  But that doesn't now, nor has it ever meant,
that an installer can't use the properly engineered tower of their choice
if they have a need to go taller - and some do, indeed. Go for it, with our
blessings (and full warranty coverage)!

5) And, one last thought.  We're not talking about a $50,000 turbine here.
Closer to $5K.  If you work the numbers, you might be surprised to find
that it makes more sense to put in two turbines on 45-foot towers than one
on a 120-foot tower.  IF the terrain, vegetation, structures and other
turbulence sources make that feasible. And, if course, there are also
places where installing a wind turbine doesn't make economic sense - or
common sense - and in those cases we'd rather say, "thanks but no thanks."
 Which brings us back to the original poster's question.  And the point
where I'll drop back into the shadows in respect for the wishes of the list
mod.

Best wishes all and, if you have specific product or training questions,
I'll keep watching and helping as I can.

Respectfully,

Ross
Training Manager - Southwest Windpower
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