Erosion to the tips of wind turbine blades affects the productivity and longevity of the turbines, costing billions globally. Putting a swimming cap on the tips to combat erosion is a unique solution that is rapidly growing in popularity.
In five days of average rotations, the outermost tip of a wind turbine blade covers a distance corresponding to Earth’s circumference. The speed of its rotation averages at 350 km/h, as it is simultaneously exposed to the elements in the form of sunlight, freezing temperatures and water. These elements degrade and abrade a turbine blade’s tip, cutting short both the productivity and longevity of turbines – something estimated to cost billions globally.
When news of the sector’s problems with erosion reached Danish subsupplier PolyTech‘s office in western Denmark, Director Mads Kirkegaard evaluated that the company had the requisite competencies to develop a product that could solve the issue, which it then set out to accomplish.
The solution ended up being a so-called soft shell made of polyurethane, and it was named Ever Lasting Leading Edge (ELLE). Put simply, it can be compared to a swim cap for turbine blade tips, Kirkegaard explains. ELLE is installed on blade tips and functions as an abrasion-resistant, shock-absorbing protective layer. The project’s development began 2012, and the company had a product to bring to market in 2016. Starting expenses were around DKK 100 million, Kirkegaard approximates. He characterizes the product’s development as “the most extensive development work the company has undergone to make a single product.”
Thus, it came as a disappointment for the company when orders for only 100 units were received in 2016.
“We have made a solution for an industry-wide problem, for which we had expected quicker and more spontaneous reactions. However, they apparently wanted to evaluate the product, which they have used 2016, 2017 and 2018 in doing. The industry has a healthy conservatism and skepticism toward new things, and one can grow tired of that when standing with something new. But it is healthy to not constantly change things,” says Kiregaard.
The trial period was lengthy, as wind turbine manufacturers and energy companies themselves wanted to test the product, which needed to be installed for one operational season in order to test the effect. Sales have now picked up, and PolyTech has this year supplied 1,500 ELLEs globally, and demand is in steep incline.
According to Kikegaard, PolyTech delivers to the “most influential and largest wind turbine manufacturers in the industry”. However, as none of the these companies wishes to be named in connection with degraded turbines and losses in the billions, it has not been possible to gather specific information on PolyTech’s clients.
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EUR 53 million for an offshore wind farm
The business potential for offering a solution for weather-worn turbines was large, as problems were expected to increase at the same pace as blades grew longer. The longest blades were under 50 meters when the company began to develop the product – they are currently 80 to 100 meters in length,
Kirkegaard emphasizes. “The entire industry has been behind in points, because they have know these problems would arise for some time. But the industry could recognize the need. Although we were only one out of 100 companies to develop a solution we claimed would work. And that has probably been the largest barrier. The difference is that we in fact supply an entirely different product – one that actually works,” he says.
Kirkegaard estimates that clients would end up paying around EUR 53 million for blade-tip protection for a medium size offshore wind farm. Whereas it would cost approximately EUR 1.3 million if Polytech is able to install ELLEs at the factory before the turbines are installed. Even though these may sound like large sums, it would cause the overall price of wind energy to decline, Kirkegaard insists. The product will extend the life-cycle of turbine blades and play a role in lowering operating costs throughout a turbine’s 25-year life-cycle.
It is difficult to estimate the total savings afforded by the new softshell. Energy loss from compromised blades is dependent on several factors such extent of damage and price per KWh.
“In a modeled example, a 3 percent production loss for a 400 MW offshore wind farm in the North Sea with 60-70 turbines would amount to DKK 20 million in productivity loss, if the turbines are allowed to operate for one year without repair,” PolyTech states.
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–Source: Energy Watch