http://www.wind-works.org/articles/RobertDreeszensRoofMountedWindTurbinesinAlaska.html

Robert Dreeszen's Roof Mounted Wind Turbines
October 25, 2006


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The following is a letter to Paul Gipe from Robert Dreeszen about roof mounted wind turbines.


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Robert Dreeszen's through the roof mounted wind turbines. Photo by Robert Dreeszen.


Paul:

I am a retired IBM engineer living in a very remote area of Alaska who is hooked on renewable energy. I am not soliciting advice just merely passing along some photos and very limited experiences you might utilize to advise starry-eyed fools like myself who go off spearing windmills without advice.

The first and foremost thing that drove me to roof mounts was basic economics. Tundra without cement anchors doesn't work and cement is around $60 a bag by the time it gets to my doorstep. I mounted mine through the roof and dug a hole under an access lid I made in the floor of the building to allow the pole to be dropped far enough to position a ladder against the tower for maintenance. Yes they transmit vibration and noise to the building but it is unoccupied most of the time. Yes they probably have a higher frequency of failure than say an 80 foot tower.

I have examined the NREL data on the H40 and it is seems I have been very fortunate to have survived my less than ideal mounting choice as long or longer than their tower mount.

In my case "average" wind is misleading because as you know its the beneficial wind that matters for production versus the nonproductive high gust type willlawaw winds we are famous for. I am not disputing your published advice in fact I am trying to add to it.

I am enclosing a photo showing a very illustrative example of that. After a very heavy ice storm followed by 80+ mph winds(measured on my weather station) a portion of one blade of the center (Air) 303 shown over my shoulder separated and the resulting vibration convinced me the building was coming down. I shot another blade off with my AR15 to solve the problem. Shooting anything in a 80+ mph crosswind is a challange. Add the feeling that you are a WW1 Ace shooting through the propeller and I feel very fortunate to have taken only 3 shots. In case anyone is curious a single blade will still revolve at 80 mph, but the vibration is minimal compared to 2 something.
Robert Dreeszen, less one roof mounted wind turbine. Photo by Robert Dreeszen.



I installed a Whisper 200 at the lodge next door recently with a 50-foot tilt up tower using the grip hoist I purchased after reading your book and found it to be the absolute key to a smooth installation. I spent many unecessarily sleepless nights worrying about "getting it up". It all went very well but I will be interested to see how it takes nine years in our conditions like the roof mounts shown have.

I have read all the NREL data, talked to several dealers and have come to the conclusion for conditions like mine the "heavy metal" like the Proven etc would be better in the long run than replacing the less expensive types several times like I have. I say this because after nine years of experience I know that but if I was back at the point without that knowledge I would opt for the less expensive especially because I am that rare breed that likes to pay my own way and don't beleive in handouts. The only heavy metal I've seen in my area was via grants. Heavy metal=heavy cash initial investment but you have to look at the total cost of doing business. I am not trying to sell my philosophy just the fact that a quality product fairly priced for the masses will promote more initial involvement in the movement but it depends on the individual what the outcome will be.

I have read with intrest your very candid comments on the some of Southwest Windpowers products and having used them agree with you completly. You are doing the right thing. They need to build a better product at a lower cost and the entire program will benefit. I spent 31 years as a Large Systems Engineer with IBM turning turds into ice cream cones because the "Sunshine Pumps" (salesmen) were masters of hype. Hype will kill you when the wind meets the blades.

Keep up the good work.

Bob Dreeszen
Outlet Lower Ugashik Lake AK
Bob's Photo Gallery

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