Carbon Retention Efficiency in Bamboo-Based Engineered Products: Linking Biomass Processing and Biogenic Carbon Retention

Bamboo-based engineered products have attracted increasing attention because of their renewable origin and long-term carbon storage potential. However, conventional life cycle assessment (LCA) mainly evaluates greenhouse gas emissions and cannot quantify how efficiently biomass-derived carbon is retained during manufacturing. Therefore, this study proposes carbon transfer efficiency (CTE) as a complementary indicator for assessing retained biogenic carbon in bamboo-based engineered products. Based on plant-scale manufacturing data from a representative bamboo scrimber factory in China, CTE was quantified together with the cradle-to-gate carbon footprint. Carbon loss distribution among manufacturing stages and sensitivity to key process parameters were further analyzed. Results showed that 65–78% of the initial biogenic carbon was retained in the final product. Unit separation and secondary machining accounted for more than 70% of total carbon loss, whereas adhesive application and hot pressing dominated greenhouse gas emissions but caused little direct carbon loss. Material-loss-related parameters exhibited substantially greater influence on CTE than energy-related parameters. These findings demonstrate that carbon retention efficiency and greenhouse gas emissions characterize different dimensions of environmental performance. Integrating CTE with LCA provides a more comprehensive framework for evaluating carbon storage and low-carbon manufacturing of bamboo-based engineered products.