Mapping of Meteorological Observations over the Island of Ireland to Enhance the Understanding and Prediction of Rain Erosion in Wind Turbine Blades

James W K Nash,Iasonas Zekos,Margaret M Stack

doi:10.3390/en14154555

Abstract

Leading edge erosion is becoming increasingly important as wind turbine size and rainfall are predicted to increase. Understanding environmental conditions is key for laboratory testing, maintenance schedules and lifetime estimations to be improved, which in turn could reduce costs. This paper uses weather data in conjunction with a rain texture model and wind turbine RPM curve to predict and characterise rain erosion conditions across Ireland during rainfall events in terms of droplet size, temperature, humidity and chemical composition, as well as the relative erosivity, in terms of number of annual impacts and kinetic energy, as well as seasonal variations in these properties. Using a linear regression, the total annual kinetic energy, mean temperature and the mean humidity during impact are mapped geospatially. The results indicate that the west coast of Ireland and elevated regions are more erosive with higher kinetic energy. During rain events, northern regions tend to have lower temperatures and lower humidities and mountainous regions have lower temperatures and higher humidities. Irish rain has high levels of sea salt, and in recent years, only a slightly acidic pH. Most erosion likely occurs during winters with frequent rain infused with salt due to increased winds. After this analysis, it is concluded that Ireland’s largest wind park (Galway) is placed in a moderate-highly erosive environment and that RET protocols should be revisited.

Highlights

Received: 28 May 2021Accepted: 20 July 2021Published: 28 July 2021Publisher’s Note: MDPI stays neutral with regard to jurisdictional claims in published maps and institutional affiliations.Licensee MDPI, Basel, Switzerland.To combat the effects of climate change, there is a global shift towards the development and integration of renewable energy, primarily solar panels and wind turbines
The differences were more pronounced for monthly humidity standard deviations, with standard deviations being smaller for the model when considering rain intensity, these were not considered significant enough to be included here as they mostly affected spring and summer months at nonrated tip speeds
The models developed here suggest that the western region of Ireland is a erosive environment, especially in the mountainous regions west of Cork, i.e., Kerry and Galway, where kinetic energy was predicted to be the highest

Summary

Introduction

Received: 28 May 2021Accepted: 20 July 2021Published: 28 July 2021Publisher’s Note: MDPI stays neutral with regard to jurisdictional claims in published maps and institutional affiliations.Licensee MDPI, Basel, Switzerland.To combat the effects of climate change, there is a global shift towards the development and integration of renewable energy, primarily solar panels and wind turbines. Wind park operators aim for their turbines to meet their expected life time (20+ years) with minimal repair work. This is highly dependent on the environmental conditions in which they are placed. Damage caused by impacts from other projectiles, including hail [1,2,3], sand [4,5,6,7], insects [8,9] and birds, contributes to the degradation They are less understood and site specific, with early research on hail erosion displaying little erosion damage [3], insects preferring warm humid air for flight [9], sand being mainly present in dry, arid areas or certain coastal sites [7] and turbine siting and development aiming to minimise bat or bird strikes. Severe erosion (Figure 1b) can occur in as little as 2 years [11]

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Conclusion