Cast Iron Skillet

Material Composition Assumptions

The default reference cast iron skillet is modeled as a standard 10-inch diameter pan weighing 2.2 kg (4.85 lbs). A typical 10-inch skillet weighs 5 pounds on average, consistent with industry standards from major manufacturers. The material composition assumes:

• Cast iron alloy: 96-98% iron, 2-4% carbon by weight
• Silicon content: 1-3% (controls graphite formation)
• Trace alloying elements: <1% manganese, chromium, sulfur, phosphorus
• Manufacturing method: Electric induction furnace melting (modern standard) rather than traditional cupola furnaces
• Raw material mix: 70% recycled steel scrap, 20% pig iron, 10% ferroalloys and carbon additions
• Pre-seasoning: Multiple thin coats of vegetable oil (approximately 15g total)

This specification represents typical modern cast iron cookware production, emphasizing the energy-intensive melting and forming processes that dominate the carbon footprint.

Manufacturing Geography

The default manufacturing region is China, which produces the majority of global cast iron cookware. China’s electricity carbon intensity is 581 gCO2/kWh, significantly above the global average of 480 gCO2/kWh. This high grid intensity reflects China’s continued reliance on coal-fired power generation, though wind and solar reached a record 16% share in 2023.

Chinese foundries typically use electric induction furnaces or electric arc furnaces for melting cast iron, which are cleaner than traditional blast furnaces but remain highly electricity-dependent. Energy costs typically account for 5-7% of overall operating costs in metal casting foundries, with electricity consumption for melting representing the largest energy use.

The choice of China as the default region reflects both market reality and conservative emissions assumptions, as Chinese production often involves higher carbon intensity due to both grid mix and manufacturing scale efficiencies.

Regional Variation

Manufacturing Region	Grid Intensity	Estimated CCI Score	Adjustment vs Default
China	581 gCO2e/kWh	48 kgCO2e	Baseline (0%)
United States	369 gCO2e/kWh	35 kgCO2e	-27%
European Union	290 gCO2e/kWh	31 kgCO2e	-35%
India	713 gCO2e/kWh	53 kgCO2e	+10%
Global Average	480 gCO2e/kWh	42 kgCO2e	-13%

Regional variations primarily reflect differences in electricity grid carbon intensity, as switching from cupola furnace to induction furnace can double cumulative energy demand depending on grid composition. US foundries predominantly use electric arc furnaces, while maintaining cleaner grid electricity than China.

Provenance Override Guidance

Suppliers can submit the following data types to override the default CCI score:

1. Environmental Product Declaration (EPD) - Third-party verified LCA data following ISO 14025 standards for cast iron products
2. Electricity consumption and grid mix data - Actual kWh usage per unit during melting, forming, and finishing operations with regional grid emission factors
3. Raw material composition and sourcing - Percentage of recycled scrap vs. virgin pig iron, with supplier-specific emission factors for each input material
4. Energy audit results - Detailed breakdown of natural gas, electricity, and other fuel consumption across all manufacturing processes
5. Transportation distances and modes - Actual logistics data for raw materials inbound and finished product distribution, including packaging materials and weights

Priority should be given to electricity consumption data given that casting yield, electricity grid, recycled content, and furnace technology are the primary factors affecting environmental impacts in cast iron production.

Methodology Notes

• Scope definition: The CCI score represents cradle-to-gate emissions including raw material extraction, transportation to factory, and manufacturing through completion of the finished, seasoned skillet

• Functional unit: One complete 10-inch cast iron skillet (2.2 kg) ready for consumer use

• System boundaries: Cradle-to-gate assessment following ISO 14044 standards, with impacts summed across all unit manufacturing processes

• Excluded phases: Use-phase emissions, end-of-life recycling benefits, and consumer transportation are excluded from the score

• Key data source: Based primarily on University of Michigan parametric LCA model finding 1.6-3.0 kg CO2e/kg for US ductile iron products (mean: 2.2 kg CO2e/kg) adjusted for Chinese manufacturing conditions

• Major limitation: Energy waste is found in all plants, and significant variations exist between foundries based on equipment age, maintenance, and operational efficiency that are not captured in this average estimate