LM Wind Power announces 73.5 m turbine blade

Dynamic testing of a turbine blade at LM Wind Power's test facility in Denmark. (Picture courtesy of LM Wind Power, www.lmwindpower.com.)
Dynamic testing of a turbine blade at LM Wind Power's test facility in Denmark. (Picture courtesy of LM Wind Power, www.lmwindpower.com.)

The new LM 73.5P LM Wind Power blades will be installed on Alstom’s 6 MW offshore wind turbines, mainly in European waters. The blades are expected to be ready for installation at Alstom prototype sites in Europe over the winter of 2011/12. The giant blades will travel at a speed of more than 320 km/h and generate power equivalent to the yearly requirements of over 6000 European households.

Speed to market

Jan Kristiansen, Vice President, Product Development at LM Wind Power, expects to present the first prototype 73.5 m blade in Denmark at the end of this year.

“The size of these impressive structures has more than doubled over the past decade alone, and although this has of course demanded the development of new materials, design and technology along the way, the new 73.5 m blade is built on our progressive accumulation of know-how. This ensures that even though it is more than 10 m longer than our recent world record blade, it is still based on a proven concept.”

“Speed to market is important in the fast-moving wind energy industry. In order to make the best possible blade available to our customers with least delay, our product development and manufacturing engineers have to work very closely together – as one team," Kristiansen explains.

"One example is the way our in-house mould experts have produced a special prototype mould with a transparent surface. This allows for full-scale manufacturing trials where our engineers are able to follow the critical polyester infusion by visual inspection.”

Blade design and production

The 73.5 m blade is based on LM Wind Power proprietary profile, developed in its wind tunnel in Denmark. The company reports that the use of advanced materials enables it to design and manufacture relatively lighter glass fibre and polyester blades for the length.

The prototype blades will be produced in the company’s Lunderskov factory in Denmark, which is currently producing the LM 61.5P2.

According to Roland Sundén, CEO of the LM Wind Power Group: “This new blade builds on the innovative features developed for our recent blade launch, the GloBlade® which has proved to be tremendously successful, offering an additional annual energy production of 4-5% compared to standard blades.”

Increasing blade size

The 73.5 m blade was developed by LM Wind Power engineers in Denmark. This team has produced more than 140 000 blades which are now installed around the world.

When LM Wind Power began production in 1978 the blades were 5 m long. LM Wind Power was the first to exceed the 60 m limit and is now the first to put blades longer than 70 m into production.

The company says it is already in discussions with a number of Asian wind turbine manufacturers about making blades longer than 80 m.