Automotive Parts

Material Composition Assumptions

The default bill of materials for mixed automotive parts is based on a representative vehicle material mix:

• Steel and iron: Approximately 55% by mass (body structure, chassis, drivetrain components) — BF-BOF steel at ~2.2 kgCO2e/kg
• Aluminum: Approximately 12% by mass (engine blocks, wheels, heat exchangers, body panels) — primary aluminum at ~8-12 kgCO2e/kg
• Polymers and composites: Approximately 10% by mass (bumpers, interior trim, dashboards, wire insulation) — average ~3-5 kgCO2e/kg
• Rubber: Approximately 5% by mass (tires, seals, bushings, hoses) — ~3 kgCO2e/kg
• Glass: Approximately 3% by mass (windshield, windows) — ~1 kgCO2e/kg
• Copper and wiring: Approximately 2% by mass (electrical harnesses, motors) — ~4-8 kgCO2e/kg
• Other (fluids, coatings, textiles, electronics): Approximately 13% by mass — variable

The CCI score of 3.8 kgCO2e per kg represents a mass-weighted average across these material categories for a typical ICE (internal combustion engine) vehicle’s parts, including the energy for forming, machining, and finishing operations. Polestar’s 2024 LCA confirms that material production and refining represent approximately 38% of total vehicle lifecycle climate impact.

Manufacturing Geography

The default assumes a blended global automotive manufacturing region.

• Grid intensity: 450 gCO2e/kWh (blended estimate across major automotive manufacturing countries). Individual countries vary: China 565, USA 390, EU 300, Japan 460, South Korea 450 gCO2e/kWh.
• Rationale: The automotive supply chain is globally integrated. A vehicle assembled in Germany may contain steel from China, aluminum from the Middle East, polymers from the USA, and electronics from South Korea. The blended approach reflects this reality.

The automotive industry has committed to net-zero targets under the SBTi Automotive Sector Standard, which requires accounting for Scope 1, 2, and 3 emissions across the full value chain.

Regional Variation

Region	Grid Intensity	Estimated Score Adjustment
EU (Germany, France)	~300 gCO2e/kWh	-10% overall (saves ~0.4 kgCO2e); higher EAF steel share
USA	~390 gCO2e/kWh	-5% overall; 70% EAF steel share reduces material emissions
Japan	~460 gCO2e/kWh	Approximately baseline; efficient BF-BOF operations
China	~565 gCO2e/kWh	+10% overall (adds ~0.4 kgCO2e); coal-dominant grid and BF-BOF steel
India	~700 gCO2e/kWh	+15% overall (adds ~0.6 kgCO2e); growing production base

Note: Material source and production route (e.g., BF-BOF vs. EAF steel, primary vs. recycled aluminum) have a larger effect than assembly location grid intensity. Scope 3 upstream materials represent 66% of the total score.

Provenance Override Guidance

A supplier or manufacturer may override the default CCI score by submitting:

1. Automotive-grade Environmental Product Declaration (EPD) or Product Carbon Footprint per ISO 14067, covering specific part categories.
2. Material composition declaration with supplier-specific emission factors for steel, aluminum, polymers, and other major inputs.
3. Factory energy data including renewable energy procurement and CHP (combined heat and power) utilization.
4. Green NCAP or equivalent LCA data for vehicle-level assessments that can be allocated to component level.
5. Recycled content documentation for steel (EAF scrap-based), aluminum (secondary ingot), and polymers (post-industrial/post-consumer recycled).

OEM sustainability reports from Volvo/Polestar, BMW, Mercedes-Benz, and Toyota provide component-level emission data that qualifies as valid provenance overrides.

Methodology Notes

• CCI score of 3.8 kgCO2e per kg represents a mass-weighted average for mixed automotive parts, based on typical vehicle material composition and material-specific emission factors. The score is elevated above simple steel (2.2 kgCO2e/kg) by the inclusion of aluminum (8-12 kgCO2e/kg) and copper (4-8 kgCO2e/kg), which have high per-kg intensities despite lower mass shares.
• Scope breakdown: Scope 3 dominates at 66% (2.5 kgCO2e/kg), reflecting upstream material production (steel, aluminum, polymers, rubber, copper). Scope 2 is 21% (0.8 kgCO2e/kg) from factory electricity for stamping, machining, welding, and surface treatment. Scope 1 is 13% (0.5 kgCO2e/kg) from direct combustion in heat treatment furnaces, paint booths, and curing ovens.
• Aggregate category: This is an aggregate metric across all automotive part types. Individual components vary significantly: a stamped steel bracket may be 2.5 kgCO2e/kg while a cast aluminum housing may be 10+ kgCO2e/kg.
• EV vs. ICE: Electric vehicles have a different material mix (more copper, aluminum, and battery materials; less cast iron and exhaust system steel). EV-specific automotive parts are expected to have a higher per-kg footprint than ICE equivalents due to increased aluminum and copper content.
• Functional unit: One kilogram of mixed automotive parts, cradle-to-gate, including forming and finishing operations.
• Data gaps: Tier 2 and Tier 3 automotive suppliers often lack published carbon footprint data. The estimate relies on material-level emission factors applied to industry-average material compositions rather than supplier-specific data.