Second-generation bio-based plastics are becoming a reality - Non-renewable energy and greenhouse gas (GHG) balance of succinic acid-based plastic end products made from lignocellulosic biomass

Bio-based and bio-degradable plastics such as polybutylene succinate (PBS) have the potential to become sustainable alternatives to petrochemical-based plastics. Polybutylene succinate can be produced from bio-based succinic acid and 1,4-butanediol using first-generation (1G) or second-generation (2G) sugars. A cradle-to-grave environmental assessment was performed for PBS products in Europe to investigate the non-renewable energy use (NREU) and greenhouse gas (GHG) impacts. The products investigated are single-use trays and agricultural film, with incineration, industrial composting and degradation on agricultural land as end-of-life scenarios. Both end products manufactured from fully bio-based PBS and from partly bio-based PBS (made from bio-based succinic acid and fossil fuel-based 1,4 butanediol) were analysed. We examine corn (1G) as well as corn stover, wheat straw, miscanthus and hardwood as 2G feedstocks. For the cradle-to-grave system, 1G fully bio-based PBS plastic products were found to have environmental impacts comparable with their petrochemical incumbents, while 2G fully bio-based PBS plastic products allow to reduce NREU and GHG by around one third under the condition of avoidance of concentration of sugars and energy integration of the pretreatment process with monomer production. Without energy integration and with concentration of sugars (i.e., separate production), the impacts of 2G fully bio-based PBS products are approximately 15–20% lower than those of 1G fully bio-based PBS products. The environmental analysis of PBS products supports the value proposition related to PBS products while also pointing out areas requiring further research and development.