Update:For original the article, I used Excel to do the analysis and produce the histograms. Since putting this analysis together, I have loaded the raw data into an Oracle database to do some more extensive analysis. On using the Oracle data, two things have become evident. Firstly wind speed accuracy to the nearest meter isn't accurate enough, especially for the low wind speed sites like Timaru. Secondly, I realised that Excel used different bin ranges to what I anticipated. The grouping of 1 m/s is actually 0.1-1.0 and 2 m/s is 1.1-2.0. Again this has a large effect on the power output calculations for low wind speed sites. As an example my Excel based analysis estimated the Thinair turbine as producing 2,889 kWh annually at Timaru. My more accurate Oracle analysis estimates only 1,094 kWh.
I have now re-made the charts. The three charts with histograms still use accuracy to the nearest meter (1 m/s is now 0.5-1.4, 2 m/s is 1.5-2.4 etc.). Note that they still over-estimate electricity production. The last two charts now use wind speed data to one decimal place and their estimates are far more accurate. 11/1/2011
Back in August I posted an article on an Analysis of Timaru's Wind. This is a follow-up to that article, where I compare the wind profile of Timaru and Baring Head (near Wellington) against the Power Output curves of some commonly available micro wind turbines.
Here's the list of turbines that I'm comparing. Added to the bottom of the list is the Siemens SWT-2.3-82. With an 80 m blade diameter, this is no micro wind turbine. It is in fact the turbine that Meridian Energy are using in the West Wind wind farm near Wellington.
These are the power curves used for the relevant turbines. I've just used a straight line from cut-in speed, through to maximum output and taken that through to 20 m/s. In reality a power curve doesn't follow a straight line, but for the purposes of this exercise they make a reasonable approximation. More...