Assessment of the rain and wind climate with focus on wind turbine blade leading edge erosion rate and expected lifetime in Danish Seas

Our motivation for investigating the rain and wind climate in the Danish Seas is recent news on leading edge erosion on wind turbine blades at several offshore wind farms. The costs related to turbine blade repair are high. In this study we investigate the rain and wind climate at five coastal and three inland weather stations in Denmark. The coastal stations have much higher frequency of heavy rain than inland stations, in high wind conditions. The hypothesis is that leading edge erosion mainly develops during these few extreme events. The leading edge erosion rates and expected lifetime are calculated assuming similar turbines to be in operation at the eight site. The results of two damage increment models show similar results for the coastal stations but differ for two out of three inland sites. The kinetic energy model shows four times high erosion rates at the coastal sites versus the two inland sites. The accumulated rain model shows site independent erosion. The expected life is on average 3 years of the two damage models. The erosion safe mode control, i.e. reduced wind turbine tip speed during extreme rain events, is presented with relative profit from 2.8 to 4.8%. (C) 2019 The Authors. Published by Elsevier Ltd.