How to determine optimal windmill placement to maximize production?

How can I add automatically the maximum number of points (dots) with 6m diameter and 100m distance each point from other into an area. The dots will present the windmill base (6m) and I want the maximum number of points with 100m distance (Ratio) each in order to reach the highest level of production.

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What GIS software are you using? You can add appropriate tags to specify this. – blah238 Feb 3 '13 at 19:37

1 Answer

In ArcGIS you can use Hawth's Tools to generate your points or in QGIS you can use Vector->Research Tools->Random Points or Regular Points.

However, you say the points will represent windmill bases and you want to maximise production. So, personally, I would not use either of these methods. Maximising windfarm production is dependent on much more than packing turbines into the available space. You need to consider windflow, wind-sheer and especially turbulence and wake losses and how these factors are influenced by the local terrain and surface roughness.

With regard to the latter point I would question your spacing of 100m. A good rule of thumb for minimum spacing is an ellipse defined by 5 times the rotor diameter in the prevailing wind direction and 3 times in the cross-wind direction. Some developers prefer 6 and 4 and some even 7 and 4. Since you intend to maximise production with multiple points, this sounds like a commercial windfarm and that suggests a typical blade length of 35 to 40m and a rotor diameter of 70m-80m. So your minimum cross-wind spacing should be around 210m-240m and your down-wind spacing should be around 350m-400m.

The only variation on this scenario would be if your turbines are sited in one of those rare locations where there is a fairly laminar flow from one direction 90% of the time (i.e. NOT Europe). In such a situation you could greatly reduce the cross-wind separation but would probably want to err towards a 7 time rotor diameter down-wind spacing.

Wake losses not only reduce energy production but also that turbulence increases your maintenance frequency and costs. Wise positioning of turbines compared to simply packing them in can often mean the same energy production for fewer turbines and given that a single commercial turbine can easily cost £1.5 million or more (not to mention the additional access tracks, cabling, delivery and subsequent maintenance, if you can save even one turbine through efficient positioning, it is worth it.

Perhaps you are using a very large number of small turbines to justify the 100m spacing, though even a small turbine with a rotor diameter of 30m, 100m might be fine for the cross-wind separation but will be bad news in the down-wind direction (unless you don't mind wrecking their gearboxes and transmission). In that case, you may have legitimate reasons for choosing small turbines (perhaps due to visibility issues or a radar ceiling) but, from an efficiency point of view you may want to consider fewer larger machines and make savings in not only infrastructure and maintenance costs but also environmental impact. Alternatively, consider a completely different site!

To calculate potential wind turbine locations, I would not use a general-purpose GIS package like ArcGIS, SAGA or QGIS but use a wind-farm package like WindFarm, WindFarmer, WindPro, WAsP or OpenWind together with a decent DTM and local wind data. Such tools have optimisation routines that will help you position turbines in your site to maximise production (of course, with experience, it is also possible to do this by eye - but for that you will need many wind farms under your belt to give that intuitive level of understanding of how the terrain you see in the DTM will effect wind flow).

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+1 for using the right tool for the job. – blah238 Feb 3 '13 at 19:48