Manufacturing Phase

Manufacturing accounts for 15-30% of lifecycle emissions across most products, though variation is enormous by industry. Energy intensity drives emissions: Primary aluminum smelting uses 15 MWh/ton; steel production uses 5 MWh/ton; plastic injection molding uses 0.5 MWh/ton. Energy source matters critically—grid electricity in China (coal-heavy, 0.6 kg CO2/kWh) vs. Iceland (hydro, 0.01 kg CO2/kWh) creates 60x emission difference for same process. Process efficiency varies widely: Metal casting has 85-95% yield (5-15% scrap); CNC machining has 50-70% yield (30-50% material removed as chips); additive manufacturing (3D printing) has 98% yield but is 5-10x slower and costlier. Waste streams are valuable: Steel and aluminum scrap is 100% recyclable within the same plant (closed-loop recycling). Machining chips are remelted. Chemical process residues may be hazardous waste requiring treatment. Renewable energy transforms economics: On-site solar + battery storage can provide 40-70% of manufacturing electricity at $0.03-$0.05/kWh, undercutting grid prices while cutting Scope 2 emissions to near zero. Green hydrogen for high-heat processes (steel, cement) costs 2-4x fossil fuels today but is declining. Digital manufacturing enables optimization: IoT sensors + AI predict equipment failures before they happen, reducing downtime 20-50%. Digital twins simulate process changes before physical trials. Additive manufacturing consolidates 20+ parts into single piece, eliminating assembly.