A new scientific paper has been published by the Department of Wind and Energy Systems at the Technical University of Denmark (DTU), in collaboration with the Wind Energy Department of the National Renewable Energy Center (CENER), as part of the AIRE project. The paper, presented at The Science of Making Torque from Wind (TORQUE 2024) conference and published in the Journal of Physics, aims to evaluate the quality of the satellite-based precipitation product IMERG for its potential use in models that predict the lifetime of wind turbine blades operating in complex terrain.
The basics
As discussed in the blog The Impact of Storms on Wind Turbines, raindrops contribute to erosion in wind turbines, particularly on the blades. Rain-induced impact erosion is considered one of the main causes of Leading-Edge Erosion (LEE), a critical issue in wind energy systems, as it can significantly affect the efficiency, performance, and durability of turbine blades, ultimately leading to increased maintenance and operational costs. LEE compromises the structural integrity of the blades, as material loss at the leading edge can result in fatigue, cracks, and even blade failure.
In 2014, the Global Precipitation Measurement (GPM) mission was launched as an international satellite-based initiative to improve our understanding of global precipitation patterns. One of the main outcomes of this mission is the Integrated Multi-satellitE Retrievals for GPM (IMERG) product. The performance of the IMERG V06B – a continuously improving dataset designed to provide high-quality, global precipitation estimates – has already been assessed in several studies, which have highlighted both its usefulness and its limitations in capturing orographic precipitation.
Why is that a problem?
As wind turbines grow larger, their blades rotate at higher speeds, making them increasingly vulnerable to wear caused by rain and wind. This kind of degradation is especially noticeable in mountainous areas, where harsh conditions accelerate the erosion process. Understanding how these factors affect blade lifespan is key to ensuring the long-term sustainability of wind energy infrastructure.
This study focuses on two main objectives. First, it explores whether rainfall intensity data from the IMERG satellite product can be used to predict blade erosion in complex terrain. The region of Navarre in northern Spain was selected as a case study due to its exceptional climatic diversity—most of the climate types found on the Iberian Peninsula are represented within its borders. This makes Navarre an ideal setting to test how well IMERG performs in challenging topographic and meteorological environments.
Second, using the data collected for the previous analysis, an estimation of the blade lifespan for the selected wind farm will be carried out.
Process
For the IMERG evaluation, its lifetime estimates have been compared with in situ data from 28 stations in Navarre. To this end, the average annual precipitation was calculated over the study period, revealing that IMERG underestimates precipitation at 15 stations—supporting the initial hypothesis regarding IMERG’s limitations in complex terrain.
Subsequently, a blade lifetime model was fed with 30-minute rainfall intensity data from IMERG, 30-minute in situ rainfall measurements, and 30-minute wind speed data from the New European Wind Atlas (NEWA), extracted at each station location and interpolated to a height of 119 meters.
Main results
The comparison confirms the findings of previous studies on precipitation in northern Spain. The discrepancies observed may result from a combination of the region’s climate, the limitations of both datasets, and their differing detection principles, as Navarre presents a challenge for both satellite products and ground-based instruments. The IMERG product captures air volume measurements through infrared and microwave sensors, while rain gauges record the weight of raindrops at specific point locations. Additionally, rain gauge data may be subject to wind-induced biases and evaporation losses. Therefore, the conclusion is that the IMERG final product requires additional calibration and adjustments to more accurately reflect rainfall variability in complex terrain before it can be reliably used to assess blade lifetimes in mountainous regions.
Regarding the blade lifetimes, the results indicate ranging from 6 to 17 years across 13 stations, with the estimates based on in situ data being, on average, longer than those derived from the IMERG product—thus underscoring the severity of erosion in the area.
Average annual rainfall from IMERG (blue bars) and in situ data (orange bars) during the period 2015-2020 for the 28 investigated stations.
Wrap up
This study addresses a growing challenge in the wind energy sector: predicting the lifespan of turbine blades exposed to harsh environmental conditions in complex terrain. It offers a step forward in integrating satellite-based precipitation data into lifetime models by evaluating IMERG’s performance. While the findings highlight underestimations in rainfall data, the research emphasizes the value of combining satellite and in situ observations to improve erosion forecasting in topographically diverse regions.
Importantly, satellite precipitation data such as IMERG provide near-global coverage, offering a critical advantage over in situ measurements, which are often sparse or completely lacking in remote areas, complex terrain, or over oceans. This broader spatial availability makes satellite indispensable for improving environmental load assessments on wind turbines where ground-based data are limited or unavailable.
For the full publication go to: Journal of Physics: Conference Series
Follow AIRE for more!
Author: Oria Pardo
Editor: Lucía Salinas
May, 2025
