Improvements in AEP calculations using IEC 61400
Abstract
There are no international guidelines for calculating the Annual Energy Production of a proposed wind farm projects. Annual Energy Production calculations are normally based on the Measure, Correlate and Predict (MCP) methodology. The correlation has historically meant finding a straight line relationship between site data and long term met station data. This correlation methodology is thus based on simple mathematical statistics; it does not include nor describe the physical properties of the wind and hence affects the accuracy of AEP results.
This paper offers an alternative and transparent methodology using the full physical properties of the wind resource as described in the IEC61400 series of international standards. The paper addresses the improvements in the central estimate (P50) as well as the uncertainties associated with this value (i.e. P90 and other values).
In 2005 SKM started to implement this improved correlation methodology to establish a relationship between met station data and wind data measured on site (either on shore or off-shore), in order to establish a long term resource data set upon which the Annual Energy Production of a proposed wind farm can be calculated with greater accuracy. The paper provides a summary of SKM’s work and provides a clear mathematical proof of correlation based on Weibull parameters.
Author:
Paul van Lieshout