Comparison of accuracies in techniques for evaluating wind power density

Reuben Kainkwa, John Kumwenda


Wind power is among important renewable sources of energy. In order to know the magnitude of wind power, appropriate techniques for evaluating it need to be investigated. Apart from the standard formula that can be used to evaluate wind power density at a site there are two more techniques namely power law exponent and Weibull two-parameter density function. However the accuracy of the latter two methods relative to the standard one has not yet been investigated. The main objective of this paper is to compare accuracies of these techniques. The wind power densities were calculated using standard formula, Weibull model as well as exponential factor of power law. The annual average of wind power density evaluated using the standard formula at the test site is 623 W/m2 while the values estimated using power law exponent and Weibull model are respectively, 629 W/m2 and 615 W/m2. The correlation coefficients between the standard method and the other two methods were found to be respectively, 0.996 and 1.000. These correlations are high enough to warrant that each one can be used to evaluate wind energy density at site with sufficiently high accuracy.

Keywords: Annual average, Wind power density, Power law exponent, Weibull model

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