Better Generation

How accurate is the Power Predictor at measuring wind speeds?

The Power Predictor has been independently tested several times and been shown to be consistent, responsive and accurate. These tests have been conducted both in wind tunnels and in the field and the results of these tests are summarised on this page...

Test One - City University

Wind tunnels can provide steady, consistent air flow – this makes it easy to test the response of the Power Predictor to certain wind speeds. In April 2009, City University in London tested a Power Predictor in their low-speed wind tunnel. The report found the overall calibration trend to be 'very good' and that the accuracy compared with other, much more expensive anemometers of the same type. One of the main tests carried out by City University was to examine the 'hysteresis' of the Power Predictor - How quickly it responds to changing wind speeds. The report concluded that the Power Predictor had extremely low hysteresis (this is good) and remains accurate even when speeds are changing quickly. The results are shown here.

Test Two - CAT

A real test of accuracy is how well the Power Predictor performs ‘in the field’. The Centre for Alternative Technology (CAT) compared the Power Predictor with their own wind monitoring system from July ‘09 to August ’09. They found a very strong correlation between the two systems, consistent results across long period of time and there is still high accuracy even at low wind speeds.

Test Three - Southampton Uni and the Energy Saving Trust

In Autumn 2009, Southampton University, with the support of the Energy Savings Trust, conducted another real-world test, comparing the Power Predictor with a Vaisala WMT50 ultrasonic anemometer. The report stated that a good relationship was observed between the Power Predictor and the Vaisala Ultrasonic anemometer and that the average difference between the two anemometers across the range of wind speeds analysed was 1.9%. Only very low wind speeds were experienced but it offered the opportunity of testing the Power Predictor at the extreme low range. The authors wrote that "The performance of the Power Predictor anemometer was comparable to that of the Vaisala device."

Test Four - City University (again!)

The anemometer was tested again with the release of the Power Predictor 2.0 in July 2010. Nine were tested at City University to confirm their accuracy and test for consistency throughout the range. Testing a number of Power Predictors in the same conditions in this way should show how results vary between different Power Predictor units and the tests found that the anemometers have a "remarkably small" spread. Additionally, accuracy found to be +/- 0.2m/s at low speeds and +/-1% at higher speeds which is an improvement on the Power Predictor 1.0.

Tests conducted in the field and in the lab show the Power Predictor to be a consistently accurate measure of wind speed. Lab tests suggest that the accuracy of the Power Predictor 2.0 is around 1% or +/- 0.2 m/s at lower speeds and further tests indicate a high level of coherence between the Power Predictors examined.

More info: Introducing the Power Predictor 2.0 Which Turbines are Included? FAQs How Do I Buy?