Wind resource assessment using mesoscale modelling. A case study at the potential wind farm site Rieppi

Abstract

The growing wind power industry, increased occurrence of extreme weather, and the need for becoming independent of fossil fuels motivate the research on accurate simulation of near-surface wind. The aim of this study is wind resource assessment at the potential wind park site Rieppi, using two on-site measurement masts, simulations from the Weather Research and Forecasting (WRF) model, and ERA-Interim reanalysis data from the European Centre for Medium-range Weather Forcasts (ECMWF). The main focus has been on 2014 for investigating monthly and seasonal behaviour of the wind. A climatology of the period 2004-2013 will be used for assessing the representativeness of 2014. The on-site measurements were compared to ERA-Interim data and WRF simulations in terms of Root Mean Square Error, correlation and Bias. Weibull distribution based on wind speed histograms and wind roses were also used for comparing the three data sources and for validating the WRF model. The obtained differences between ERA-Interim and the on-site measurements, in terms of horizontal wind speeds and prevailing wind directions, show little consistency. The obtained wind roses from ERA-Interim show little agreement to the prevailing on-site wind directions. In contrast, despite a systematically underrepresentation of strong and gusty wind speeds, the WRF model provides more accurate simulation results than the ERA-Interim data. The simulated wind directions and low to moderate wind speeds show high consistency to the on-site measurements. The local wind resource maps obtained by WRF provide valuable information about the local wind patterns in the area. These factors show that the WRF model is a versatile and useful tool for early stage wind resource assessment, even in complex terrains like at the Rieppi site.