Life cycle assessment of wind turbine blade recycling approaches in the United States

Abstract

Most wind turbine blades reaching end-of-life are sent to landfill where embedded cost, energy, and materials are lost. To avoid landfilling future blades, a broad range of recycling and material recovery approaches have been proposed as solutions in the U.S., each with benefits, challenges, and varying levels of technical maturity. The approaches include 1) cement co-processing, 2) mechanical recycling, 3) pyrolysis, 4) microwave pyrolysis and 5) solvolysis. While these approaches are all capable of recovering various forms of materials for use in secondary markets, there are trade-offs between material circularity, reducing harmful environmental emissions, and cost-effectiveness for the U.S. market. Life cycle assessment (LCA) is a critical step needed to compare these trade-offs and determine where future research and development should be focused. As a result, some previous LCA has been performed on recycling approaches. However, attempts to quantify and compare greenhouse gas emissions across a broad range of technologies have been limited, particularly within the U.S. market where landfill availability and costs do not hinder disposing of wind blades. This work addresses this limitation by presenting a detailed comparison of LCA greenhouse gas emissions and material yields from a range of wind turbine blade recycling approaches in the U.S. The LCA presented in this work includes baseline results, as well as a variety of sensitivity and scenario analyses that look at the impact of process modelling uncertainty, future energy mixes, and other critical input parameters. Overall, results show that mechanical recycling and microwave pyrolysis have the lowest net greenhouse gas emissions. However, the value of mechanically recycled materials is highly uncertain, as mechanical recycling generates a mixed feedstock that may underperform compared to virgin materials. Cement co-processing has higher net emissions than mechanical recycling or microwave pyrolysis but does generate a value-added feedstock that offsets virgin material from mining for cement production. Other advanced thermal and chemical recycling methods such as pyrolysis and solvolysis have higher net emissions due to increased energy consumption but are also highly sensitive to thermal energy sources within the model.

Glass Fibre Composites Recycling Using the Fluidised Bed: A Comparative Study into the Carbon Footprint in the UK

“…This study has shown that mechanical recycling could be a low-carbon solution to mixed GRP waste streams, including wind blade waste. This is in close agreement with other studies that investigated the impact of GRP mechanical recycling in North America [13] and China [14]. Unlike FBR, which utilises all the waste GRP mass, the "coarse" fraction remains following the classification stage of mechanical recycling.…”

“…This work has shown, however, that while using GRP as feedstock in EfW facilities can reduce landfill burden, this results in significantly higher GWP than simply landfilling. This has also been shown to be the case in North America [13] and China [14]. Given the UK (and other global) commitments to Net Zero 2050, incinerating GRP waste for energy alone must also be avoided.…”

“…Extensive research has been recently devoted to the development of composite recycling techniques, which have led to various recycling strategies, each at different Technology Readiness Levels (TRL). In recent years these technologies have been widely reviewed in terms of the methods under development [6,7], TRL [8], recovered material properties [9,10], ongoing challenges [11], optimisation pathways [12], and environmental impacts [13,14].…”

“…Sproul et al conducted a comparative LCA to assess GHG emissions and material yields from a range of wind turbine blade recycling approaches (cement co-processing, mechanical, pyrolysis, microwave pyrolysis, and solvolysis recycling) in the U.S [14]. Sproul et al determined that both mechanical recycling and microwave pyrolysis result in the lowest net GHG emissions.…”

Lifecycle Assessment of Strategies for Decarbonising Wind Blade Recycling toward Net Zero 2050

“…Over recent years, numerous researchers have assessed the carbon footprint associated with different end-of-life (EoL) strategies for GFRP wind blade structures. Sproul et al conducted a comparative LCA to evaluate GHG emissions and material yields across various wind turbine blade recycling methods (including cement co-processing, mechanical, pyrolysis, microwave pyrolysis, and solvolysis recycling) in the United States [22]. They found that both mechanical recycling and microwave pyrolysis yield the lowest net GHG emissions.…”