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Vertical Axis Wind Turbines

October 20, 2009
Paul Gipe

Quick Grab a Stake--Mag-Wind Rises from the Grave

Mag-Wind is back. Grab your children. Bar the door. The dead walk.

Worse Ed Begley and Jay Leno, those omnipresent endorsers of all things "green", have leapt to the aid of the undead. Their names and pictures are plastered across the web site of Enviro-Energies, the now parent of Mag-Wind.

Not that Ed and Jay are great at picking new technologies. After all they slapped their endorsements on PacWind, another rooftop vertical axis wind turbine that was going to storm the world. Last I heard Ed was trying to get that PacWind turbine off his house. I suspect that Jay got rid of his too.

I've written about Mag-Wind before. See Mag-Wind Pyramidal Power. and I feature it in my new book Wind Energy Basics as an example of how to evaluate the wild claims of inventors.

I thought Mag-Wind was dead, put in the grave with all the other "innovative" or "outside the box" products that bedevil us in wind energy.

Alas, the monster has risen. A major Canadian newspaper, the Globe and Mail, somehow thinks that Jim Rowan, Mag-Wind's "inventor" is an innovator, a Canadian Steve Jobs.

Ok, enough of the rant. What does Enviro-Energies say on their web site about the Mag-Wind? Not much really. That's a lesson they learned. If you don't post energy estimates then you don't have pesky, self-styled wind experts making fun of you.

They "offer" several different size wind turbines. Let's take the biggest of their 10 kW model and see how it stacks up.

The rotor is 10 ft by 26 ft or about 3 m by 8 m. Thus the rotor intercepts about 24 m² of the wind stream.

At a standard power rating, this "turbine" should be reasonably rated at 5 kW. That's not bad. It's only overrated by two times. That's a lot better than the original Mag-Wind and significantly closer to reality than the Wind Cube.

Nevertheless, the Mag-Wind is a simple Savonious rotor and their performance is significantly less than that of conventional wind turbines. The "new" Mag-Wind's performance is probably half that of a conventional wind turbine so that the turbine is probably overrated by four times.

Of course there's no evidence either way that the turbine generates electricity at all. It does spin on their web site, but spinning is the easy part.

And I would be remiss if I didn't point out that Enviro-Energies and Mag-Wind's inventor Jim Rowan claim that the rooftops where this turbine would be installed accelerate the flow. Hypothetically, that would make up for all the other inefficiencies.

However, data from real-world tests of operating wind turbines on rooftops in Great Britain have been damning. Most rooftop wind turbines generate very little electricity and some even consume more electricity than they generate. See Warwick Wind Trials Gives Failing Grade to Rooftop Wind.

Now let's take a look at their costs. The 10 kW model will cost nearly $60,000. Taking into account that it's more reasonably a 5 kW turbine, the relative installed cost is $12,000/kW or about four times that of a commercial wind turbine. On a swept area basis the turbine costs about $2,400/m² or more than twice what a commercial turbine costs today.

To summarize, if you want to greenwash your building, buy some green paint. It's certainly a lot cheaper.

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