Sustainability assessment of the repurposing of wind turbine blades
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Date
2022
Authors
Nagle, Angela J.
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University College Cork
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Abstract
Ireland is regarded as rich in wind resources, with Wind Energy Ireland suggesting that wind generation could make Ireland a renewable superpower. Ireland has chosen to capitalise on this resource by dramatically expanding wind energy generation capacity. However, with this development of wind capacity comes the need to deal with increasing amounts of waste from the wind sector when the turbines reach end-of-life. While much of the turbine is recyclable, the blades, which are made from composite glass fibre and polymer material, is not yet economically viable to recycle. Many blades are being landfilled or incinerated at the end of their working lives. An option that is gaining in popularity is the idea of repurposing blades into useful structures.
This thesis considered the question “Can repurposing of end-of-life wind turbine blades from Irish wind turbines offer overall gains in sustainability?” Overall sustainability was by developing a Life Cycle Sustainability Assessment framework, which includes environmental Life Cycle Assessment (LCA), Life Cycle Costing (LCC) and the lesser established social life cycle assessment (s-LCA). LCA was used to first establish co-processing of the discarded blade material in Ireland as the most likely and best case scenario against which to compare repurposing solutions. Three overall scenarios were then developed based on maximizing blade consumption, the substitution of high embodied carbon materials, and serving customer segments who will benefit from circular material use such as the county councils who may be required to adhere to Green Public Procurement requirements. Based on these scenarios and customer segments, an estimated 20% of the blade material estimated to be decommissioned in Ireland could potentially be repurposed, offering reductions of 30,780 kg CO2 equivalents of emissions per year. The concept of using end-of-life blades to make bridges (termed ‘BladeBridge’) was selected from the scenarios for an in depth study. LCA and LCC comparisons against a conventional bridge and the baseline disposal method, showed BladeBridge to be environmentally less impactful than both of these scenarios. From a cost perspective, the first BladeBridge using a specific blade model will be slightly more expensive than a conventional bridge and subsequent blade bridges due to the reverse engineering required to assess the residual structural properties of the blade. However, second and subsequent bridges made from the same blade models would be less expensive. Indicators for s-LCA were developed by considering national shortfalls in Ireland’s performance against the Sustainable Development Goals (SDGs), which can be considered the world’s key performance indicators. In this way, these indicators capture a product’s ability to affect global social indicators in which Ireland most needs to improve upon. Using LCA, LCC and the SDG based s-LCA indicators, a stage/gate screening process was developed which follows the embedded systems model of sustainability. In this framework, early business ideas can be first screened for environmental and social value, and then for cost viability. This framework can help in the development of ‘purpose driven businesses.’ The research presented in this thesis combined life cycle thinking with policy considerations and business value creation, and offers contributions across all of these areas. Some examples of contributions are the positioning of LCA in the repurposing debate; the creation of a framework for life cycle assessments of products made from end-of-life material that can be used to contribute to improving globally defined social and environmental metrics; analytical tools for local authorities to implement green public procurement; and support for Ireland to decouple its renewable energy generation from the production of waste.
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Keywords
Life Cycle Assessment , Composites , Waste , Cement manufacture , Wind turbines
Citation
Nagle, A. J. 2022. Sustainability assessment of the repurposing of wind turbine blades. PhD Thesis, University College Cork.