An Integrated Carbon Footprint Calculation System Model for Net Zero Emission in the Manufacturing Industry Based on GHG Protocol and DEFRA

Manufacturing industries play a critical role in achieving Net Zero emission targets due to their significant contribution to greenhouse gas emissions. However, existing carbon footprint calculation practices often apply the GHG Protocol and emission factor standards independently, resulting in fragmented methodologies and limited decision-support capabilities. This study develops a carbon footprint calculation system model that integrates GHG Protocol emission scope classification with DEFRA emission conversion factors, supported by a decision-support framework for Net Zero emission planning. Using a Design Science Research (DSR) approach, the study produces a conceptual system model that structures activity data, emission scope classification, and standardized carbon calculation logic into a unified framework. The proposed model enables transparent aggregation of emissions across Scope 1, Scope 2, and Scope 3, while the decision-support framework translates calculation results into decision variables, scenario-based analysis, and Net Zero roadmap formulation. The system functions as a decision-support system that assists manufacturing organizations in interpreting carbon footprint results and supports Net Zero emission planning. The findings demonstrate that integrating standardized carbon accounting methodologies within a system-oriented design enhances methodological coherence, traceability, and strategic relevance for sustainability decision-making in the manufacturing sector.