Page 93

R&D into blade/rotor aeroacoustics and leading-edge erosion can enable blades to operate at higher tip speed ratios, which has benefits on reducing the chord dimension of blades, improving their transport potential.

Advanced aeroelastic modeling into dynamic stability and deflections also enables development of more slender blades that can result in narrower blade shape and controlled deflection during transport could be utilized.

Pathway specific topics such as segmented blade joints and further development of airships are noted as potential high value, even though they do not impact multiple pathways and they are not considered core competency of the U.S. DOE labs. These topics do represent opportunities that if realized, could significantly enable wide scale deployment of supersized turbines across all regions of the U.S.

As requested by the U.S. DOE project leaders, we incorporated these R&D topics into specific recommended actions and categorized them as enablers of supersized blades as follows.

10.1 Enabler 1: “Go Fast”, slender blades U.S. DOE could advance R&D to develop new blades with a slenderer form that operate at higher tip speed ratios (TSR). This offers the best near-term promise for continued incremental gains down the current LCOE trajectory of larger rotors at decreasing $/MW in the range of 75 m to 90 m blades. Continue to enable long slender blades with root and chord dimensions constrained for ground transportation. In collaboration with the transportation industry, incorporate blade bending during transport into the blade design. •

U.S. DOE has strong opportunity for R&D that enables high TSR – resulting in go-fast, slender blades: -

Industry needs help advancing technologies that enable high-lift for thick airfoils to minimize aerodynamic losses near root.

-

Aeroelastic stability issues (e.g., edgewise vibrations, flutter) are a current challenge for industry and become a bigger challenge as blades get longer and slimmer.

-

Strong opportunity exists for DOE to advance aeroelastic codes and related sensor/controls technology that are needed to design, transport, and operate long slender blades.

-

As TSR increases, leading-edge erosion and acoustic noise effects increase, and industry does not have the bandwidth to fully investigate these issues alone.

U.S. DOE’s knowledge and facilities are well suited to push further into solutions for the stiffness/deflection challenge: -

Focus on low-cost carbon fiber, downwind rotors, advanced sensing, and controls.

-

Market dynamics and economic pressures discourage OEMs from tackling these higher risk topics.

-

National Wind Technology Center (NWTC) offers an ideal facility to deploy and test new materials, rotor configurations, sensors, and controls.

-

Scaled Wind Farm Technology facility (SWiFT) offers the ability to test blades, controls, and combined turbine system interactions in a field environment.

High TSR enables blade height and width dimensions to stay in transport envelope:

DNV GL – Document No.: 10080081-HOU-R-01, Issue: C, Status: FINAL www.dnvgl.com

Page 72

Profile for DNV GL

Supersized wind turbine blade study  

R&D pathways for supersized wind turbine bladesSupersized wind turbine blade studyLawrence Berkeley National LaboratoryDocument Number: 1008...

Supersized wind turbine blade study  

R&D pathways for supersized wind turbine bladesSupersized wind turbine blade studyLawrence Berkeley National LaboratoryDocument Number: 1008...

Profile for dnvgl