If you sow wind, you shall reap power
Innovative steel products such as non-oriented electrical steel are helping to make wind turbines more efficient – and they save on natural resources.
Wind turbines contain many steel parts. This is because steel materials are rugged enough to withstand wind and weather – both on land and offshore, for 25 years and more. Also, steel materials are sufficiently energy-efficient to make wind power more and more economical.
This is where electrical steel and its special properties come to the fore. Magnetically soft steel consolidates and strengthens the magnetic flux inside the wind turbines’ generators. This way, the mechanical rotational energy can be converted into electricity without any major conversion loss.
„Performance and efficiency crucially depend on the properties of the materials.“
“Performance and efficiency crucially depend on the properties of the materials,” says Marco Tietz from
Non-Oriented Electrical Steel Application Technology at thyssenkrupp Steel Europe.
The steel producer is widely considered a technology pioneer in the area of electrical steel. The magnetic properties of this special steel have been further optimized to suit the requirements of Enercon – which is one of the main reasons behind the performance increases wind turbines have experienced over the last few years.
Electrical steel improves magnetic flux
The cores need to be reliably magnetizable for many decades, while at the same time withstanding the elements as well as considerable temperature differences. And, of course, let’s not forget about the mechanical stresses – about 25 revolutions per minute.
In order to keep these stresses to a minimum, Enercon has dispensed with the use of high-maintenance, wear-prone gear units. Instead, the generators form a single unit together with the rotor hub.
The advantage of this approach is that there are fewer moving parts, which means the turbine will have a longer service life. As well as being more economical, this approach is also better for the environment. With no gear unit there is also no need for environmentally harmful lubricants and controversial rare earths such as neodymium.
Environmentally friendly generator-production
In the east frisian foundry in Aurich Enercon produce the load-bearing parts for its turbines – rotor hubs, machine mounts or blade adapters. Each of these is several meters in size and several tons in weight.
What’s notable here is that almost half of the materials used are steel scrap sourced from the company’s own generator factory. That’s 65 metric tons of scrap from electrical steel stamping per day, collected using an advanced recycling system developed by Enercon subsidiary STA Stanztechnologie Aurich.
This material is 100% recyclable – just like any other type of steel. However, there is a small difference: The steel produced for Enercon is a special alloy designed for higher conductivity and stamping suitability. Initially, this caused Enercon a few issues when it came to the casting stage.
“After one-and-a-half years of joint development, we have now optimized the mix of materials to a degree that our electrical steel can be recycled not only in our own steel works but also in Enercon’s on-site foundry,” says Marco Tietz.
Positive environmental performance evaluation
The two companies have managed to strike just the right balance between production efficiency and recyclability. This is a sensible center path that particularly benefits the environment. “The recyclability of steel helps to reduce the environmental impact of electrical steel and decrease our CO2 footprint,” agrees Anna Meincke, an environmental engineer from the steel producer’s Technology & Innovation department. Meincke and her colleagues are responsible for assessing the environmental impact of the different types of electrical steel being produced.
„The recyclability of steel helps to reduce its CO2 footprint.“
As well as recycling, the assessments look into raw materials production as well as the materials’ processing, use, and lifecycle. The results are intended to aid the ongoing improvements to energy efficiency and sustainability. It’s working: According to a study conducted by Boston Consulting, wind turbines with a large amount of steel components save up to six times the CO2 used during the components’ production.
Non-oriented electrical steel
•can increase the energy efficiency of energy-producing rotating machines because it has consistent magnetic and mechanical properties on all of its sides.
•is predominantly deployed in electric motors, transformers, and generators because these all require constant magnetic characteristics in all directions.
•has low environmental impact thanks to its increased energy efficiency and recyclability.