Impact assessment of terrain specifics on wind energy production over semi-complex terrains

Abstract

Abstract Estimated energy production for a wind farm depends on the wind shear who is influenced by both the roughness factor and terrain specifics. Tall towers measurements allow accurate determination of the velocity profile around the mast. Away from the point of measurements the reliability of the extrapolated data depends on complexity of the terrain and the extrapolation technique applied, as the error may exceeded 30 %. In terms of this, the use of one high mast to predict the energy potential is inaccurate. However, installing more than two tall masts is expensive. Therefore, a novel approach is used to analyse the wind potential for semi-complex terrains - one tall and one short (reference) masts. The novelty in the study here is that the short mast collects wind data for high and low terrain points. The data collected shows that the complex character of the terrain significantly increases the thickness of the surface boundary layer making the data obtained with 20 m masts quite unreliable. However, the 20 m mast data provides useful information for boundary layer that is used for refinement of the tall tower wind shear. Thus, the use of high and short masts improves the estimated energy production.