A Method for Estimating Annual Energy Production Using Monte Carlo Wind Speed Simulation

Birgir Hrafnkelsson,Gudmundur Oddsson,Runar Unnthorsson

doi:10.3390/en9040286

Abstract

A novel Monte Carlo (MC) approach is proposed for the simulation of wind speed samples to assess the wind energy production potential of a site. The Monte Carlo approach is based on historical wind speed data and reserves the effect of autocorrelation and seasonality in wind speed observations. No distributional assumptions are made, and this approach is relatively simple in comparison to simulation methods that aim at including the autocorrelation and seasonal effects. Annual energy production (AEP) is simulated by transforming the simulated wind speed values via the power curve of the wind turbine at the site. The proposed Monte Carlo approach is generic and is applicable for all sites provided that a sufficient amount of wind speed data and information on the power curve are available. The simulated AEP values based on the Monte Carlo approach are compared to both actual AEP and to simulated AEP values based on a modified Weibull approach for wind speed simulation using data from the Burfell site in Iceland. The comparison reveals that the simulated AEP values based on the proposed Monte Carlo approach have a distribution that is in close agreement with actual AEP from two test wind turbines at the Burfell site, while the simulated AEP of the Weibull approach is such that the P50 and the scale are substantially lower and the P90 is higher. Thus, the Weibull approach yields AEP that is not in line with the actual variability in AEP, while the Monte Carlo approach gives a realistic estimate of the distribution of AEP.

Highlights

The objective of this research is to introduce a novel empirical simulation method and to compare it to a modified Weibull simulation method
The biggest edge that the Monte Carlo (MC) wind speed simulation has over the Weibull wind speed simulation is the fact that when calculating the Annual energy production (AEP) for a given site, the simulated values of AEP give a representative distribution of the power production of the site
Another advantage of the MC wind speed simulation is its simplicity relative to the simulation methods for wind speed that aim at including the autocorrelation and seasonal effects for AEP computation

Summary

Introduction

The objective of this research is to introduce a novel empirical simulation method and to compare it to a modified Weibull simulation method. The empirical simulation is referred to as the Monte Carlo (MC) wind speed simulation It is based on resampling blocks of days with the same calendar days from data over a few years to obtain a representative sample of these calender days. The modified Weibull simulation is based on fitting Weibull densities to eight wind direction sectors, estimating the probability of wind measurement coming from a given sector and simulating independent samples using the probabilities of the sectors and the fitted Weibull densities. This simulation based on the Weibull distribution is referred to here as the Weibull wind speed simulation

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