Author Topic: Honest answer needed please  (Read 1001 times)

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Offline junglejoe39

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Honest answer needed please
« on: September 27, 2015, 12:39:34 AM »
Considering buying a small wind turbine. A 600 watt max 12 v model and mounting it 15 feet high.. I have 1400 watts of solar. Im in Michigan with a 12 mph average wind speed but found a large percent of that is between Oct. and May. For the same price as the wind turbine and pole I can buy 300 watts of solar. Anyone have any Idea which will produce more power over these coming winter months ? The turbine has a 62 in swept area and is 5 blade and is supposed to make 400 watts with 25mph wind. Also any idea how much I will lose from my solar in winter ?

Offline MadScientist267

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Re: Honest answer needed please
« Reply #1 on: September 27, 2015, 03:03:54 AM »
Hi JungleJoe and welcome to the forum.

I'm not a wind guy myself, but hung around long enough to give a basic run down... Since you've tossed a question in at the end that's more my speed, I'll go ahead and drop my two cents about the turbine first...

15 feet off the ground is likely to give you very poor performance, even if the unit can deliver stated output. Air nearer the ground is turbulent, which will cause a turbine to wag it's tail a lot and not produce much. Generally speaking, the higher you can get it off the ground (above tree line seems to be a bare minimum from what I've read over the years) and the further away from any other objects (out in a large field is good), the better the turbine will perform. The gurus will add to this, no doubt, but hopefully this gives you a rough heads up.

Solar loss in winter.. Well, there's basically 4 main factors that play into it... your elevation above the equator, the amount of precipitation you get (snow), what kinds of obstructions you have south of the panels (trees, etc), and how your panels are mounted (eg fixed/tracking, flat/angled and what angle (if fixed)...

Winter days get short, which really puts a pinch on the "solar day", which can translate into only a few hours of useable light on the clearest of days...

The angle of incidence (angle the light hits the panels) causes power to drop off, as well as the light traveling thru more air causing less energy to reach the panels to begin with.

If the sun has to get above any kind of a tree line to reach the panels, this will cut production significantly (particularly as you get further north) because PV does need direct light to perform optimally, of course.

There is one up side to winter, PV is more efficient at lower temperatures, so that part of it can balance out some.

Last but not least, frozen precipitation of any real amount (pronounced "visibly white") will render PV dead in the water. This readily will turn to snow packed ice, which can take it's sweet time going away. Particularly so if the air is still below freezing, but even when it rises up some. If it's thick enough, you can miss some good light this way unfortunately.

Hopefully this helps you out a bit, without more info about your array, I can't add very much more to that... And as I said, I'm a solar guy myself; the wind vets can tell you a lot more about what a turbine will do in a given situation.

Also, there are maps available that tell can give you a good idea of what to expect from your general location; nothing however beats collecting data about the area (via sensors and observation of existing equipment you have already installed). Logging is definitely your friend in that area, most will say a year of data before buying whenever it's possible.

Steve
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Offline rossw

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Re: Honest answer needed please
« Reply #2 on: September 27, 2015, 03:29:06 AM »
Agree with most of what Steve said, generally.

I've been living completely off-grid for a little over a decade, running a large home, two offices, workshop etc.
I have a nominally 1kW wind turbine at about 25 feet, but I'm on top of a hill that's about 500' above most of the surrounding land.
Basically, it's rubbish. I needs to be bigger and higher. And I need to live in an area that's far more consistent wind-wise.

I have 3.5kW of PV installed (and recently another 4.5kW in the shed ready to mount), most on tracking arrays. At the time, PV was around $10/W, so tracking made sense. It was also impractical to just over-size to make up for short days and cloud.

Given the current mix (certainly in my country), with it getting harder and harder to get approvals for wind turbines (or insurance!), the cost of PV around 50c/W without much effort, and improving battery technology, you're probably far far far better off getting extra PV, bigger batteries, and an inexpensive genset to make up for the days sun just doesn't do it for you.

Offline junglejoe39

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Re: Honest answer needed please
« Reply #3 on: September 27, 2015, 11:47:50 AM »
Thank you guys VERY much. My stuff is grid tied to save$ and Im trying to eke out every penny lol. Most of my solar is on a hinged roof over my south facing deck so I can keep the north south pretty much on but not much I can do east west at least for now. I planned for snow removal and hopefully it will help with the ice I did not foresee. I think Im just going to have to try the wind turbine. There is actually a huge wind farm about 50 miles north of me. If the wind turbine does not work out I have a few wacky ideas for the PMA including a home gym that stores kinetic energy. I need the exercise and feel Id be more motivated to work out if I was getting paid to lol.