Wind Turbine Blades Keep Growing

At the forefront of every design decision being made in the wind industry today is the technology versus cost equation, a new report by MAKE Consulting reminds us. In past years, leading vendors deploying wind turbines with the highest levels of performance were able to cultivate a price premium for their products. In today’s market, global competition has narrowed those price premiums and challenged profitability for all industry participants.

Increasing energy capture through the use of larger rotors has the single largest impact on wind turbine cost of energy. Turbine OEMs are pushing the envelope of design, moving toward aero-elastic tailored blades that enable heightened turbine performance while minimising fatigue loads. Carbon fibre and automated production processes are being harnessed in support of these new advanced airfoil designs. Other turbine OEMs are focused on traditional materials and improving blade aerodynamics to achieve similar results, while others still are focused on blade trailing edge enhancements that minimise noise.

It is clear that technology will play a critical role in determining the success of wind energy market participants throughout the value chain. Advanced technology development will shape the future of the global wind industry and prevent it from moving toward a commoditised space. As a consequence, industry leaders will distinguish themselves from the competition by successfully navigating an increasingly demanding market environment with a structured design approach that strikes the proper balance between price and performance.

Blades

Blades are the turbine’s primary energy conversion components and continue to be a critical focus area of wind turbine technology. In 2010, the continuing evolution of blade lengths to address a need for more efficient low wind speed turbines was the dominant trend in this segment of the technology space. This market dynamic has not abated, and as the first wave of low wind speed turbines reaches commercialisation, a host of alternative offerings are being announced to further supplement product portfolios.

The industry as a whole continues to focus its onshore efforts in the 1.6 MW-3.5 MW segment, while the offshore segment has moved away from 5 MW systems and is graduating to 6 MW-7 MW offerings to cope with larger offshore farms at greater water depths and greater distances from shore. The interplay between onshore and offshore wind turbine portfolios has left a noticeable gap in the 3.5 MW-5 MW segment. The enhanced production of smaller MW and multi-MW systems cannot be replicated with larger multi-MW offerings due in part to:

  • Transport issues that demand blade segmentation and on-site blade assembly;
  • Untenable material costs that outweigh incremental energy capture;
  • Supply chain limitations in areas such as hub production.

Despite the issues associated with blade design for larger multi-MW turbines, blade length evolution has not reached its peak, and lessons learned from R&D endeavours will facilitate yet another push by turbine vendors to accomplish the following:

  • Drive their latest IEC III turbines into IEC II wind classes (with conditions on turbulence intensity, wind shear, and other wind farm climate characteristics);
  • Interpolate between existing blade offerings to enhance existing IEC II wind turbines while new low wind speed turbines are proven out;
  • Sharing of blade designs among MW-class and multi-MW-class turbine platforms.

It must be noted that the proliferation of various blade lengths cannot be pursued ad infinitum, as the economics associated with blade mould production/utilisation as well as third-party certifications will reduce the cost efficiency of these new products. A new blade mould can cost upward of US$5 million, while certification can take more than a year. As such, turbine OEMs must examine their regional deployment objectives carefully to ensure that industrialisation goals can be met while ensuring enough flexibility to meet the demands of a global client base.

Global Blade Materials Market

A report from industry consultants AMI Consulting, published in January, calculates that the global demand for materials in the production of wind turbine blades grew by over 20 percent per annum in the last five years. The market for wind turbine blades has been one of the fastest growing of any composite application with strong growth in Europe, North America and more recently Asia.

The value of the global composite blade market is estimated at €4 billion in 2011, of which around €1.5 billion was raw materials.

Increasing effort is being invested in designing blades for maximum power generation and this requires careful attention to material composition, material processing and of course overall design. The link between generating capacity, blade size and materials usage is also crucial.

To maximise return on investment, the average blade size is getting longer and heavier requiring greater quantities of raw materials. As blade length and weight increase beyond current norms increased sophistication in blade design, materials and manufacture are required. 

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