Accurate carbon accounting is increasingly required for manufacturing firms to meet regulatory, investor, and supply-chain disclosure demands. However, implementation remains challenging due to inconsistent system boundaries (Scope 1/2/3), fragmented operational data, and uncertainty arising from missing activity records and emission factors.

This study proposes a reproducible and auditable, data-driven carbon accounting framework that bridges the gap between carbon accounting guidance and operational implementation. The approach integrates production and process records (orders, process steps, and equipment logs), energy consumption data, bill of materials (BOM), and logistics records into a traceable activity-based emission model. To ensure boundary consistency, we introduce an explicit scope mapping procedure that standardizes Scope 1/2/3 allocation and reduces the risk of double counting across upstream, on-site, and downstream activities. To address data gaps and uncertainty, we represent emission factors as ranges and apply Monte Carlo uncertainty propagation, producing both point estimates and confidence intervals for product-level and process-level carbon footprints. The framework is demonstrated through a manufacturing case study, where it generates auditable carbon breakdowns by process step, material, and logistics stage, and identifies the dominant contributors to total emissions. Results show that uncertainty ranges are non-negligible and vary significantly across scopes, highlighting the importance of transparent uncertainty reporting. The proposed framework provides a scalable foundation for operational carbon management, internal decision support, and credible sustainability reporting.

Keywords

Carbon accounting, manufacturing, Scope 1/2/3, uncertainty quantification, traceability.