Unpacking bio-based alternatives to ethylene production in Brazil, Europe, and the United States: A comparative life cycle assessment

• Published in: Journal of cleaner production Vol. 428; p. 139376
• Main Authors: Zanon-Zotin, Marianne, Bergman-Fonte, Clarissa, Nogueira Morais, Taísa, Barbosa Maia, Pedro Luiz, Carvalho, Lucas, Angelkorte, Gerd, Oliveira Fiorini, Ana Carolina, Rua Rodriguez Rochedo, Pedro, Portugal-Pereira, Joana, Szklo, Alexandre, Schaeffer, Roberto
• Format: Journal Article
• Language: English
• Published: Elsevier Ltd 20-11-2023
• Subjects: Bio-based materials; Climate change mitigation; Energy transition; Ethylene; Life cycle assessment; Plastics; Life cycle assessment; Plastics; Climate change mitigation; Energy transition; Ethylene; Bio-based materials
• ISSN: 0959-6526; 1879-1786
• DOI: 10.1016/j.jclepro.2023.139376

Plastics account for 4.5% of global greenhouse gas (GHG) emissions, which are hard-to-abate due to the use of fossil fuels as feedstock. Our study develops a cradle-to-gate life cycle assessment of bioethylene production, exploring 33 pathways across Brazil, the EU, and the US. It aims to understand whether substituting fossil-based ethylene with bioethylene contributes to lowering carbon emissions, and in which of the relevant bioenergy-producing regions/countries the valorisation of biofuels as feedstocks would provide a less carbon-intensive bioethylene production. Results indicate that bioethylene production through catalytic dehydration of sugarcane bioethanol in Brazil presents lowest GHG emission. This pathway could deliver up to −2.1 kg CO2e/kg ethylene when accounting for biogenic carbon storage in long-lived applications such as infrastructure. In contrast, beef tallow performs the poorest as a raw material, regardless of whether land-use change (LUC) emissions are considered. When biogenic carbon storage is factored out, none of the pathways outperforms conventional fossil-based steam cracking; however, some are within the fossil-based range indicating potential indirect benefits through reduced refinery utilisation. Our study underscores that biomaterials production as a climate mitigation strategy must be on par with circular economy measures and the conservation of native forestry ecosystems. These results are particularly relevant to policymakers and industries seeking to align polymer manufacturing with sustainability objectives.
•Bio-ethylene cradle-to-gate GHG emissions were assessed for 33 pathways.•Sugary, starch, lignocellulosic and oily crops are raw materials for bio-ethylene.•Local specificities such as biogenic carbon storage and land-use are critical to LCA GHG emissions.•Sugarcane bioethanol dehydration route yielded 2.1 kgCO2e captured per of kg ethylene.•Climate mitigation and circular economy policies must be designed coherently.