Study Evaluates R&D Pathways for Supersized Wind Turbine Blades

March 7, 2019

We are pleased to announce the release of a new study led by DNV GL "R&D Pathways for Supersized Wind Turbine Blades.” The report evaluates key design, manufacturing, and transportation options to advance long, “supersized” blades for cost-competitive land-based wind energy.

The move toward progressively longer wind turbine blades has been a lasting trend in the industry. Even-longer blades make it possible to increase energy capture, potentially reducing the overall cost of wind energy nationwide and opening up lower wind-speed sites for potential development. But, without additional innovation, transportation challenges could curtail further blade growth opportunities.

This study focused on blades with lengths of 75 to 115 meters, compared to the current U.S. average of 55 meters for newly installed wind projects. Typical rail and road blade transportation using current methods can accommodate blades up to around 67 meters in length.

Building on input gathered by DOE in a workshop and via a public request for information, DNV GL analyzed three possible pathways that might enable these supersized blades:

  • Innovative transportation, including both (a) rail and truck transportation of full blades that includes controlled bending of the blades, and (b) air transportation of full blades with lighter-than-air cargo airships
  • Segmented blades delivered through traditional rail and truck transport and with onsite assembly of the blade segments
  • Full onsite manufacturing of complete blades

Based on available data and two hypothetical project sites, each pathway was assessed quantitatively, estimating the cost of delivered blades (considering the cost of the equipment and transportation) and the contribution of the blades to system-level wind levelized cost of energy (LCOE). Tradeoffs related to commercial readiness and the geographic breadth of applicability were also discussed. 

The analysis results summarized in the figure below show that the use of lighter-than-air cargo airships or controlled blade-bending (i.e., bending of blades to navigate curves) in rail transport may present the most promise for delivery of supersized blades to project sites at a neutral or reduced overall system LCOE. Because lighter-than-air airships are not yet commercially available, the analysis of that option is speculative. Moreover, rail transport with blade bending has yet to be attempted, and there are also geographic limitations on where it might be viable.

 

While other pathways studied increase blade-related LCOE, requiring cost reductions in other aspects of the wind system to decrease total LCOE, segmented blades offer the unique ability to deploy supersized blades across the entire United States. In addition, turbine manufacturers already have some experience with this solution. On-site (mobile) blade manufacturing, meanwhile, faces challenges such as low equipment utilization and the expense and complexity of commissioning and operating mobile manufacturing plants.

DNV GL identified a number of R&D activities that could make valuable contributions to the viable development of supersized blades. These recommendations are feeding into the DOE-funded “Big Adaptive Rotor” project to assess and prioritize technology needed to develop a cost-competitive land-based 5-MW turbine with 100-meter-long blades.

Read the full DNV GL study as well as a short factsheet summarizing the study's results at: https://emp.lbl.gov/publications/supersized-wind-turbine-blade-study

A DNV GL press release can be viewed here.

We appreciate the support of the U.S. DOE’s Wind Energy Technologies Office in making this work possible, and thank Wood Mackenzie, the National Renewable Energy Laboratory, Sandia National Laboratory, and the many wind industry experts who contributed their insights to this research.

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