Comparison of greenhouse gas emission reductions in wood-based plastics production in Japan

The Japanese government aims to produce and promote 2 million tons of bioplastics by 2030. With 25.05 million hectares of forests, Japan has significant potential to utilize wood as a feedstock for large-scale bioplastic production. In this study, we assessed the sustainability of bioplastics produced from wood in Japan, while focusing on greenhouse gas (GHG) emissions and the long-term carbon neutrality associated with forest management. Life cycle assessment (LCA) was conducted across four scenarios, considering different feedstocks: conventional petroleum (S0), woodchips (S1), woodchips and hydrogen (S2), and captured CO 2 and photovoltaic-produced hydrogen (S3), with S1–S3 being alternative scenarios. A forest management model was employed to ensure a sustainable wood supply and estimate the long-term carbon balance of forest management for bioplastic production. Compared to conventional S0, the alternative scenarios S1 and S2 exhibit higher emissions of 0.68 and 0.60 t CO 2 -eq/t-bioplastics, while scenario S3 emits less 0.72 t CO 2 -eq/t-bioplastic. S1 and S2 were projected to achieve carbon neutrality under the constraint of forest management, with S2 reaching it around 10 years earlier. However, producing 2 million tons of bioplastics domestically is impractical, given the limited artificial cedar forests. Overall, this study presents novel insights into GHG emission reduction within the context of bioplastic production in Japan.