Bigger and better blades for wind turbines – Horizon Magazine blog

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Europe is full of wind – and puts it to good use. Wind energy is expected to make the biggest contribution to the EU’s renewable energy targets.

This makes it a key element of Europe’s climate neutrality, a target the EU aims to achieve by 2050. Local technologies and tools will help Europe meet its climate targets while improving the competitiveness of the EU. EU wind ecosystem on the global stage and create new green jobs.

Winds of change

In 2020, wind power satisfied around 16% of electricity demand in Europe, with a majority of onshore installations and a fraction offshore, both floating and fixed.

Europe intends to increase the stake considerably, with projections to increase total wind power generation by around 50% over the next 5 years. The increase in energy performance will be achieved not only by a greater number of installations, but also by wind turbines capable of generating more energy than their predecessors and which are less out of service for maintenance and repairs.

Wind turbines are huge, fast (considering their size and weight) and subject to very harsh working conditions. Imagine a football field spinning through the air at around 15 to 20 rpm in some of the windiest places on Earth.

From 2000 to 2018, the average length of wind turbine blades more than doubled. The new models are expected to reach lengths in excess of 85 meters by 2025. Some offshore turbines could sweep the sky in the near future with blades 110 meters long – a spinning diameter of two football pitches end to end.

The larger the blades, the faster the tips move and the greater the erosion of their leading edges. The industry has made tremendous technological advancements in materials, design and manufacture. Still, implementing larger blades that deliver more power with less wear is a huge challenge.

Fortunately, the EU has a plan that includes improving resilience to degradation – which will only increase with larger blades and more and more extreme weather events – and better non-destructive monitoring to detect defects early on, even during manufacture.

An armor that “gives”

To withstand the forces of nature and the tremendous forces generated by the rotation itself, the blades are made with multi-layered “armor”. Typically, the outer layer erodes during operation and the inner layers can peel off.

According to Asta Å akalytÄ—, director of research and development at Aerox Advanced Polymers, SL, although the life of a turbine is theoretically 25 years, current mid-size systems typically require extensive maintenance of around 10 years. due to the deterioration of the blades. The most recent ones with larger rotation diameters show severe erosion from the second year of service.

To solve this problem, Aerox has developed AROLEP®, a proprietary and pioneering state-of-the-art protection system that is now ready for commercialization thanks to the work of the LEP4BLADES project.

Unlike conventional coatings you might find on pipes, Aerox’s coating is viscoelastic, meaning it gives way or, more specifically, deforms under stress and rebounds. As akalytÄ— explained, “this is achieved with a combination of two polymers with different complementary properties. The AROLEP® coating can absorb high speed and high frequency impacts caused by raindrops and other particles hitting the leading edge of the blade. The tailor-made modification of the polymer properties ensures that the coating and blade materials work together so that impact effects are dissipated throughout the blade structure. ‘

Independent performance tests have shown that AROLEP® protects blade integrity better than any other available solution – and it can be used for new blades as well as those already in service.

Market adoption is expected to have significant ripple effects on consumers: significant savings in maintenance, repair and downtime translating into lower energy costs. In the meantime, Aerox continues to improve the formulation while targeting new coatings and adhesives for future blades that could help make wind turbine manufacturing a zero waste business.

And an angel to watch over them

Coatings are designed to minimize damage, but they cannot prevent it completely. Improved structural health monitoring technologies could detect faults early before the scale tips over, and repair or replacement creates financial and practical problems as large as the turbines themselves.

Blade failures are a major problem for the wind turbine industry. About a third of the billions of euros annually spent on the operation and maintenance (O&M) of wind turbines are for the inspection and / or repair of blade coatings.

Until now, it was impossible to identify the internal defects of the blade coatings. Visual inspection is the method of choice during manufacture and maintenance, but it does not detect defects hidden beneath the surface.

Even state-of-the-art inspection methods, such as inductive and ultrasonic technologies, are insufficient when it comes to wind turbine blade coatings. They require contact which can damage the boards and coatings, especially if they are wet, and they cannot analyze individual layers, only the total thickness.

One way to look inside multilayer coatings can be in the terahertz (THz) region of the electromagnetic spectrum – between microwave and infrared frequencies. He can “see” through things and identify what’s inside – along with its chemical composition and electrical properties – in a non-destructive, non-invasive, and non-ionizing way.

Until a few decades ago, its potential was difficult to harness in part due to our inability to effectively generate and detect waves. But that is changing with the proprietary THz technology developed specifically for industrial use by das-Nano and brought to the market as part of the NOTUS project.

According to Eduardo Azanza, CEO of das-Nano and NOTUS Coordinator, “NOTUS is the first non-contact tool for non-destructive material inspection specially designed for the inspection of wind turbines. It can perform in-depth characterization of the individual layers of any coating structure and slide, regardless of materials, allowing quantification of interlayer adhesion. ‘

NOTUS is available in three versions for applications throughout the blade lifecycle supporting development, manufacture, operation and even inspection by reception staff or insurance companies. According to Azanza’s estimates, this could save wind farm operators around 10% of O&M costs.

And wind farms are not the only ones to benefit from it. NOTUS works with all kinds of multi-layer substrates including metal, composite and plastic. It adapts to flat and curved surfaces and to dry, wet and hardened paints.

THz technology also enables the electrical characterization of advanced materials such as graphene, 2D materials, thin films and bulk materials.

Azanza said, “das-Nano brought to market NOTUS, harmless technology for rapid, non-destructive inspection of every product in a manufacturing line, identifying defective parts as early as possible.”

The research in this article was funded by the EU. If you liked this article, consider sharing it on social media.


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