At the mercy of the weather: researchers help wind turbines last longer

EU-funded researchers have developed tools and models to predict how rain and sand wear down wind turbine blades and affect their performance, helping wind farms limit damage and power losses. By Gareth Willmer On wind farms from Denmark to the Canary Islands, turbine blades face an unlikely enemy: rain. Their tips can reach 360 km/h, and at that speed, raindrops can gradually wear away the leading edge of a blade. Worn blades produce less electricity, just as Europe leans more on wind for its clean energy. Rain is not the only culprit. Sand and hail can also damage blade surfaces, which makes it important to understand where erosion is most likely to occur and how it can be limited. Dr Beatriz Méndez López, a wind energy researcher at Spain’s National Renewable Energy Centre (CENER) in Sarriguren, Navarra, brings experience from both industry and academia to the challenge. Trained in engineering and computational fluid mechanics, she worked in Spain’s wind energy and aeronautics industries before joining CENER in 2011. She now coordinates AIRE, an EU-funded initiative investigating how weather affects turbine performance and durability. The stakes are high. In 2025, wind generated more than a third of the EU’s renewable electricity. Looking ahead, the European Commission expects wind energy to meet over 40 per cent of EU electricity demand by 2050. Getting there will mean using larger turbines that reach higher into the atmosphere and exploring more demanding sites, both onshore and offshore. “In the future, we’ll need much more wind energy to meet EU renewable energy targets,” said Méndez. “We need to make wind turbines as efficient as possible and able to operate effectively in different locations.” Energy mixes differ from country to country, so wind matters more in some than in others. Ásta Hannesdóttir, part of the AIRE team, researches wind and energy systems at the Technical University of Denmark’s Risø campus in Roskilde. She knows the difference first-hand: her native Iceland has abundant hydropower and geothermal energy. “But in some locations, such as Denmark, where there’s almost no hydropower, wind power is critical.” To help developers choose sites and design more effective wind farms, the AIRE team is looking beyond wind speed alone. The researchers are using measurements from wind farms to improve models of how turbines perform in real-world conditions, taking account of rain, sand and wind conditions found at the heights reached by modern turbines. They are modelling how blade erosion develops and calculating how much electricity it can cost operators. They have also investigated how slowing turbines during heavy rain could reduce damage, while developing blade shapes designed to withstand harsh weather. “The aim of the project is to better understand how wind turbines operate under real-world weather conditions,” said Méndez. The team brings together 11 universities, companies and research and innovation centres from six countries. Working across borders gives the researchers a wide range of conditions to compare, with onshore and offshore sites from Denmark and the UK to the Canary Islands. Understanding precipitation is particularly challenging. The team has measured it at heights of up to about 3 km above the ground, recording what falls, how big the drops or particles are and how fast they fall. “We’ve learnt that the effects of precipitation are complex, and there is still much to understand,” said Méndez. “Its relationship with wind is not always straightforward: rain doesn’t necessarily mean strong winds, or vice versa. The effects also depend on whether the terrain is flat or more complex.” Hannesdóttir added that measuring and simulating the effects of rain is difficult, too. “We can place two instruments side by side and still get different readings. We don’t usually see that with wind.” The researchers are exploring practical ways to limit the damage. One approach is to reduce blade speed during heavy rain, when the risk of erosion is high. Although this means generating less electricity in the short term, reducing wear could help blades last longer and maintain their performance over time. The team has also designed new blade shapes intended to improve resistance to weather-related damage. The AIRE team has brought its models and data together in an online toolbox, helping other researchers and the wind industry assess risks and improve turbine design and operation. The resources include a blade erosion risk atlas showing modelled rain erosion risk across Europe, a planning aid for wind farms in conditions such as rain and sand, and models that estimate how much electricity turbines may lose as their blades wear. The toolbox is open source, meaning anyone can use and adapt it. “We hope the AIRE toolbox will provide a lasting resource that researchers and industry can use, validate and build on to improve the reliability of wind energy,” said Hannesdóttir. The resources were developed in close collaboration with industrial partners, including the Danish division of Siemens Gamesa Renewable Energy, Spain’s Capital Energy and France’s Engie. “They have tested the tools during their design and sent their feedback to the developers. The use of these models should reduce uncertainty and costs, and increase power production, helping blade manufacturers and wind farm operators improve their designs and operations,” said Méndez. The AIRE research is part of a wider European effort to improve wind energy forecasting and turbine design, alongside two other EU-funded initiatives, FLOW and MERIDIONAL. Researchers on these have also been developing models and methods to predict how much electricity wind farms will produce and the stresses they will experience. Together, the three teams have contributed to WindLab, an open-access online knowledge and data hub that anyone can search and use. It currently contains more than 1 100 datasets – collections of measurements and computer simulations – from 27 contributing organisations. The data covers everything from wind, rain and blade condition measurements to computer simulations of the atmosphere. They include information on turbines on land and at sea, as well as airborne systems such as kites. For Méndez, the long-term goal is to make wind energy generation more predictable and less risky. “We hope AIRE’s legacy will be a better understanding of a site’s wind potential and the weather-related challenges it presents, helping to reduce the financial risks of future projects,” she said. “More reliable wind energy will help stabilise energy prices and make it easier to integrate renewables into the system.” For Hannesdóttir, the aim is clear. “We want to demonstrate that erosion can be predicted and actively managed using practical open-source tools.” As turbines grow larger and are deployed at more challenging sites, they encounter a wider range of atmospheric conditions. By improving understanding of wind and weather, researchers hope to help turbines withstand the conditions they will face – and keep producing the clean electricity Europe is counting on. This article was originally published in Horizon, the EU Research and Innovation Magazine.