battery-less VAWT [RE-wrenches]

Tue Feb 5 20:58:03 PST 2008

Matt,

Yes, I must elaborate. I was more referring to the Windterra VAWT example.

Before making any decisions for this type of turbine, we have of course
criteria that we need to address first.

If the mounting structure is part of the turbine price/package and no
reinforcements have to be made (which is a small percentage) it would be an
alternative solution, however the roof construction has to meet minimum
standards set out by the manufacturer of the turbine and the roof needs to
be carefully inspected and confirmed to make sure it is o.k.

For wind speed and turbulence, I would say, urban environment is a no-no,
because of the reasons you pointed out below, but let me point out that I
think that a VAWT has "less" of a problem with turbulence than a HAWT.
Therefore the roof type and orientation & direction of prevailing winds (not
obstructed by trees, bush etc) are other criteria we look at. 

You have to consider a lot more factors, before considering a VAWT. I think
it is a lot more complicated as far as siting goes.

That is why I said "little place in the market".

I am going to visit a testfield in the Netherlands this year of 7 small
turbines at a maximum height of 15 metres where the Turby VAWT and Skystream
are also present. It is a output test for two years.
We will see what how these turbines perform under local conditions.

Wilco Vercoelen
Dommelvalley Green Power

-----Original Message-----
From: Matt Tritt [mailto:solarone at charter.net] 
Sent: February 5, 2008 9:13 PM
To: RE-wrenches at topica.com
Cc: Wilco Vercoelen
Subject: RE: battery-less VAWT [RE-wrenches]

Wilco,

I'm trying to make sense of your statement "the price per kilowatt is
reduced because there is no tower cost".

This is a basically untrue statement/assumption. You still need a mounting
structure, whether or not it's a tower-  or something "else". Roof mounting
will require, in most cases the reinforcement of the roof itself to prevent
structural damage to the building in high winds. Roofs are not designed to
carry large external loads in the form of a turbine (or anything else), just
snow and ice. Snow and ice are evenly distributed over a large area, not
located in one big blob. :-)

The absence of a viable windstream on a roof top means that your turbine
will not produce commercially useable amounts of energy, period. No matter
that you are higher than the surropunding land, there is virtual ground
tubulence on every roof, unless you know something that no one else does.
Please elaborate.

Matt
---- Wilco Vercoelen <w.vercoelen at dommelvalley.ca> wrote: 
> 
> Dear Kelly,
> 
> You are absolutely right. Rooftops in general are not recommended, because
> of turbulence, vibration etc, etc. and there isn't a lot of wind at these
> heights anyway, however the price per kwh produced is lower because no
tower
> is required reducing the overal installation costs. Producing about 55% of
a
> Skystream, installed at 10m, but half the price installed could still be
an
> interesting option for some applications. Like I said, we think it has its
> own little place in the market. It will be limited and more actual field
> data must be provided.
> The single most important issue is the SWCC certification in place for the
> small wind turbine market and get rid off all the phoney stuff.
> 
> Wilco Vercoelen
> Dommelvalley Green Power
> Utopia, Ontario
> 
> 
> -----Original Message-----
> From: Kelly Keilwitz [mailto:kelly at whidbeysunwind.com] 
> Sent: February 4, 2008 1:21 AM
> To: RE-wrenches at topica.com
> Subject: Re: battery-less VAWT [RE-wrenches]
> 
> 
> Wilco,
> I wasn't aware of this outfit, thanks. Their "testing" facility in
Kelowna,
> BC is ~ 5 hours from us - in fact I was through there last week.
> 
> However, the first availability was stated as August, 2007 and they're
> marketing it as roof-top mounted. I'd like to know that one of those
300-lb,
> 64 s.f. spinning objects has stayed up and operational on someone's roof
(in
> a windy spot) for a few years before I recommend it to a customer.
> 
> Rooftop mounting, even if the turbine stays up, and doesn't vibrate, still
> is missing the main point: there just isn't much fuel there. The cost of a
> tower can be justified simply by Energy ~= velocity cubed.
> 
> -Kelly
> Kelly Keilwitz, P.E.
> Whidbey Sun & Wind, LLC
> Renewable Energy Systems
> NABCEP Certified PV Installer
> 987 Wanamaker Rd, 
> Coupeville, WA 98239
> PH & FAX 360-678-7131
> sunwind at whidbeysunwind.com
> 
> 
> 
> On 2/1/08 8:51 PM, "Wilco Vercoelen" <w.vercoelen at dommelvalley.ca> wrote:
> 
> > 
> > 
> > Have you guys looked at Windterra http://www.windterra.com/
> > It is a fairly new Canadian 1.2kW direct grid-tie VAWT, but based on the
> > specs and pricing we think it has its own place in the market. We do not
> see
> > it as an alternative to a horizontal wind turbine but rather as a type
> that
> > can be used under certain circumstances, e.g. higher rise buildings.
> > We know that for example the Dutch Grid-Tie Turby (European market) is
> > pretty effective and well developed, but again in its own little place
in
> > the market. We believe that the majority of turbines will be horizontal,
> now
> > and in the future, but that doesn't mean that a well-tested vertical
> turbine
> > with actual good field test results and certifications can be a solution
> > under certain conditions. Unfortunately there aren't many out there,
> yet....
> > 
> > Wilco Vercoelen
> > Dommelvalley Green Power
> > Utopia, Ontario
> > 
> 
> 
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