Sustainable Production Optimization under Resource and Environmental Constraints: Evidence from North Sumatra’s Industrial Sector

Abstract

This study develops an energy- and emission-constrained production-allocation model for North Sumatra to balance economic performance, resource availability, and environmental limits. A quantitative applied-operations-research design used January–December 2025 operational records from 150 medium- and large-scale manufacturing establishments across six subsectors. Provincial totals were estimated using an overall expansion factor of 8.667 as a uniform-factor approximation to the stratified estimator because stratum-specific population weights were unavailable. Multi-objective linear programming with AUGMECON-R compared observed, economic-only, resource-constrained, environmentally constrained, and integrated scenarios. The economic-only solution was projected to increase contribution margin by IDR 3.32 trillion (11.7%) but also increase energy use by 5.18 PJ and greenhouse gas emissions by 0.69 MtCO2e. The integrated solution increased projected contribution margin by IDR 1.65 trillion (5.8%) while reducing raw materials by 6.6%, energy by 12.2%, water by 15.2%, greenhouse gas emissions by 21.2%, solid waste by 21.5%, and wastewater by 21.6%. Production shifted most toward rubber and plastics (+12.4%) and away from non-metallic minerals/fabricated metals (−13.3%). The Pareto frontier retained 94.7% of the economic-only contribution margin at an 80% combined resource-and-environmental ceiling, declining to 90.5% at 75% and 84.0% at 70%, indicating a sharper trade-off below approximately 75–80%. The study contributes a province-level cross-subsector framework linking production allocation with demand-side energy and emissions benchmarks for industrial efficiency and renewable-energy planning.