A Decommissioned Wind Blade as a Second-Life Construction Material for a Transmission Pole

Ammar A Alshannaq,David W Scott,Russell Gentry,Lawrence C Bank

doi:10.3390/constrmater1020007

Ammar A Alshannaq, David W Scott + Show 2 more

Open Access

https://doi.org/10.3390/constrmater1020007

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Abstract

This paper demonstrates the concept of adaptive repurposing of a portion of a decommissioned Clipper C96 wind turbine blade as a pole in a power transmission line application. The current research program is aimed at creating a path towards sustainable repurposing of wind turbine blades after they are removed from service. The present work includes modelling and analysis of expected load cases as prescribed in ASCE 74 and NESC using simplified boundary conditions for tangent pole applications. Load cases involving extreme wind, concurrent ice and wind, extreme ice, differential ice, broken conductor, and broken shield have been analyzed and governing load cases for bending, shear, and torsion have been examined. Relative stiffnesses of different parts forming the wind blade’s cross section (i.e., shell, web, and spar cap) are determined. The corresponding stresses associated with each part under the governing loads are compared to allowable strength values which are determined from composite laminate theory and modelling of the known laminate structure of the E-Glass FRP material. Stresses and deflections obtained are compared with governing reliability-based design criteria and code requirements. The results of the structural analysis indicate that the wind blade can resist the expected loads with reasonable safety factors and that the expected deflections are within permissible limits. Recommendations are provided for detailing and modification of the wind blade for a power pole application in which crossarm and davit connections are highlighted, and foundation details are emphasized.

Highlights

The wind turbine industry is expected to stockpile millions of tons of composite wind blades in the coming years [1]
This paper has presented a preliminary study on a BladePole structure in which a decommissioned wind turbine blade is configured as a tangent pole with 230 kV capacity
The BladePole application was shown to be adequate in ultimate and serviceability design limit states, in which the lowest safety factor is 4.19 and the maximum deflection is below the limit of 8% of the aboveground height (AGH)

Summary

Introduction

The wind turbine industry is expected to stockpile millions of tons of composite wind blades in the coming years [1]. Based on the proven track record of existing FRP poles with wind turbine blades that are made using the same glass fiber reinforced composite materials, a new pole configuration has been proposed [15,16]. The steel connector plates are bolted to the spar cap material (the structural carrying part of the cross-section of a wind blade). The load cases used to verify structural adequacy of any power transmission pole include extreme wind, extreme ice, combined wind and ice, differential ice, broken shield wire(s), and broken conductor(s). In. Figure 4, the analysis values are obtained for the predefined stations, and since station 11 is at the end of the wind blade (material beyond station 10 is not structurally used), properties and stresses go to zero and that is why they are not presented in the provided charts.

Comparison of Results with Governing Code Requirements

Findings

Conclusions