Turbine to power farm

[HungarianHippo]

I’m aware of a 10kw Bergey. Can you tell me the model of the 15kW? I want to look at the manufacturer’s power curve data. Bergey is generally a very well-regarded mfr, they’re a great choice

What’s your cable run (distance from turbine to meter) and what gauge cable are they recommending?

Really happy to see you’re doing a 120ft tower.

Can you get the actual wind data, beyond just the annual mean? If you want to PM your actual location I might be able to get that for you. The mean is good info but the variability it also matters a lot since the mean is strongly influenced by outliers (wind speeds in excess of your machine’s cut-out speed are “wasted”-- they’ll drive up your average wind speed, but you can’t take advantage).
Also, you’ll want to confirm that they’ve checked for turbulence intensity and it’s within your machine’s spec.

In terms of siting, as I’m sure you know any vertical obstructions will impact your production over a surprisngly large area. Rule of thumb for the “wind shade” area: for every vertical foot of the obstruction, the wind shade extends twenty times that number. i.e. 10ft tall garden shed can impact the wind energy for a turbine that’s 200ft away. Even just ground-level vegetation impacts wind speed by creating shear. Here’s a super cool “wind shade” calculator tool, that lets you model these kinds of losses. You put your turbine height and info about the terrain and obstruction (type, height, distance). It will produce a graph that shows the energy losses you can expect. It’s a little clunky to use-- some researchers in Denmark put it together–but I like the information a lot.
http://drømstørre.dk/wp-content/wind/miller/windpower%20web/en/tour/wres/shelter/index.htm

[HungarianHippo]

@Bluey

When talking about efficient, wind is more efficient than solar.

That doesn’t mean for any one location it may one or the other be more suitable.
Doesn’t help much that wind is more efficient, if the wind doesn’t blow enough and the sun shines every day where we want to decide what to use.

Yes, for utility-scale installations. But for residential sized turbines, efficiencies suffer a bit b/c they don’t have access to the good, clean wind that those the big machines enjoy 300+ft up. Wind speed increases as you go higher, and the energy contained in that wind increases exponentially. Wind energy increase is proportional to the cube of the wind speed increase. Example: At a site where mean wind speed at 30ft high is 12mph. At 120ft high, you can expect 15.5mph mean speed. So you might think “gee–just a 3.5mph increase, big whoop.” Well, with that modest speed increase, you get a 100% increase in wind energy. So that’s why a taller tower is a big deal.

Like you said, it’s all about what energy resource do you have? Combine that with what kind of siting restrictions do you face, how much power do you consume, and what’s your electricity price, etc and you can tell pretty quickly what your payback period will be. Some will pay for themselves in 8-10 years, some will be longer, some won’t make economic sense at all.

[HungarianHippo]

OP, I’ll PM you some more site-specific info. But this may be interesting for others here. Here’s a look at two different sites the OP might consider, and how they affect the wind energy s/he can capture.
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[HungarianHippo]

OP, I’ll PM you some more site-specific info. But this may be interesting for others here. Here’s a look at two different sites the OP might consider, and how they affect the wind energy s/he can capture.

Both graphs below assume that 1) you have a bunch of trees about 20 meters (66ft) tall, and 2) your turbine is 37m tall. Those trees will cause a wind-shaded area of turbulent air that reduces the amt of energy available to your turbine. It seems only logical that you should put your turbine as far away from those trees as you can, right? Maybe, but not necessarily. So let’s look at what happens if you put your turbine 80 meters away, and then just 30 meters away.

In each graph, the turbine tower is represented as a yellow column—picture your turbine sitting at the top of that the top of that yellow column. The dark gray areas have basically no viable wind energy to use and elsewhere the #s show what % of the wind energy is available to your turbine.

On the left you see the turbine at 80 meters away from the trees. Even at this distance, the trees are still sapping energy away from your turbine–it will only see 94% of the energy that would have been avail. otherwise. Look at what happens if the turbine is placed just 30 meters away from the line of trees (right graph). Here you can see that the OP’s 120ft tall turbine sits above the turbulent zone, so it receives 100% of the available wind energy flowing past it.
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