Evaluating the Environmental Efficiency of Bioplastics using Advanced Life Cycle Assessment
Bishop, George
Bishop, George
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Publication Date
2021-11-05
Type
Thesis
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Abstract
International bans on single-use petrochemical plastic products are accelerating the uptake of bioplastics to fill the gap in the market. Previous life cycle assessment (LCA) research exploring the environmental impacts from various bioplastic products has often been inadequate, leading to incomplete, biased, or misleading conclusions on their environmental sustainability. Thus, the primary aim of this thesis was to advance the understanding of the comparative environmental performance of bioplastic production, use, and disposal against conventional petrochemical plastic production, use, and disposal. This was achieved within this thesis via an extensive critical review of the published literature (Chapter 2), new analysis of plastic recycling chains (Chapter 3), and innovative consequential LCA of bioplastic value chains (Chapters 4 and 5). The research demonstrated the need for application of consequential LCA to facilitate a better understanding of the wider consequences of displacing petrochemical plastic with bioplastic. These LCAs further evaluated how possible environmental hotspots for bioplastic production could be reduced. Characterisation of petrochemical plastic recycling value chains was improved to enable more accurate benchmarking of bioplastics, where it was shown that a significant percentage of plastic from European recycling value chains is likely to end up as ocean debris. Overall, the thesis found that bioplastics can play a role in reducing global greenhouse gas emissions. However, simple substitution of petrochemical plastics with bioplastics will not drive environmental savings unless consumer behaviour and wider value chain logistics also change. Nevertheless, the uptake of bioplastics represents an important opportunity to design production pathways compatible with net-zero greenhouse gas emissions, and waste elimination in line with a fully circular bioeconomy. From this thesis, five main focal points are identified to drive environmentally sustainable bioplastic expansion: i) acquisition of environmentally sound bioplastic feedstocks, considering the wider (potentially indirect) impacts. Bioplastics derived from lignocellulosic biomass or waste were shown to have great potential for environmental sustainability, avoiding the (potentially considerable) indirect land-use change burdens from purpose grown crops. ii) Development of circular and optimised value chains for the subsequent bioplastic production, for example, introducing decentralisation of production, utilising production residues, and ensuring that bioplastics can be treated via anaerobic digestion or directed to insect feed at its end-of-life. iii) Development of strategies to generate consumer behaviour change around bioplastics, especially for consumers to identify compostable bioplastics, and to place them within a dedicated food waste collection bin if appropriate after use. iv) Investment and implementation of regulations and incentives to aid the sustainable transition to bioplastics, based on the latest research, ensuring that the proceeding bioplastics don’t just fill the market gap, but can also be restorative by nature. Such policies should support the preferred waste management hierarchy of compostable bioplastics, and safeguard against environmentally poor bioplastic feedstock acquisition. v) Increased research into the potential environmental impacts of bioplastic production, use, and disposal, considering further consequential and dynamic LCAs and full life cycle sustainability assessments. Overall, the guidance and understanding developed in this thesis will be a major asset to academic, industry, consumer, and policy stakeholders alike, enabling the rigorous assessment and design of environmentally sustainable bioplastic value chains, guiding stakeholders to bioplastics which can be more environmentally efficient than their petrochemical alternatives.
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Publisher
NUI Galway