Quantifying the effect of wind turbines on lightning location and characteristics

Abstract

This study shows and quantifies the effect of the presence of wind turbines on lightning stroke location, density, polarity, peak current and annual distribution in areas where they are installed. We analyze the CG lightning activity recorded by Météorage during 21 years (1995–2015) over a 0.5° × 0.5° area in southwestern France (2.5°E-3°E; 44°N-44.5°N). The study area includes 8 farms with 2 to 29 turbines each, most of them installed between 2007 and 2010. The results show that the rate of increase of the cumulative number and the proportion of CG strokes are significantly larger around the turbines when they are installed, e.g. ~ 4.7 and 3.4 times, respectively, in a radius of 100 m. The proportion of positive CG strokes is lower around the turbines, e.g. ~ 3 times in a radius of 200 m. The annual distribution of CG strokes around the turbines is very different from that of the whole study area, with a total proportion of 36.9% and 2.3% in winter, respectively. Case studies of daily winter storm activity show that up to 93% of the strokes detected in the study area are located in the vicinity of wind turbines. The strokes are classified in three categories: first strokes of CG flashes (~31%), subsequent strokes of CG flashes (42%) and upward self-initiated discharges produced after a previous flash in the surrounding area (~27%).