How do I calculate the carbon footprint of plastic caps and closures?

Caps are mostly polymer: multiply the PP or HDPE used per kg of caps by the resin supplier's figure, add liners and masterbatch, then add moulding or compression moulding energy per kg of good caps.

Material

• PP or HDPE resin.
• Colour masterbatch.
• Liners or wads if used.

Process

• Injection or compression moulding.
• Slitting and folding tamper bands.
• Lining, inspection and packing.

Per kg

Report per kg, or per thousand caps by weight. Lighter caps cut the resin figure directly.

Worked example: plant energy per kg (one month)

• Electricity: 70,000 kWh x 0.710 = 49,700 kg CO2
• Kg dispatched: 80,000
• Plant total: 49,700 / 80,000 = 0.621 kg CO2 per kg
• Add resin and masterbatch for the full figure

Inputs are illustrative; use your own bills and production records.

What Senseible does here

Senseible reads the plant's electricity bills (CEA grid factor 0.710 kg CO2 per kWh, CO2 Baseline Database version 21.0) and fuel invoices (IPCC 2006 defaults) into a fingerprinted Scope 1 and 2 record, the plant-level input to a per-unit figure. Bought-in materials go to the supplier evidence trail; product reports are self-declared drafts.

• Product carbon footprint calculator
• Injection moulding footprint
• PET preform footprint
• Packaged drinking water footprint
• Chemical industry

Sources: GHG Protocol Product Standard, ISO 14067:2018, Carbon footprint of products (iso.org), IPCC 2006 Guidelines, Volume 2 Energy (fuel defaults), CEA CO2 Baseline Database, version 21.0

Last reviewed 2026-10-21.