# How do I calculate the carbon footprint of an industrial gearbox?

Canonical: https://senseible.earth/answers/gearbox-carbon-footprint-per-unit

Weigh the cast housing, steel gears and shafts, bearings and oil per gearbox and multiply by supplier figures. Add machining, gear cutting, heat treatment and assembly energy, then divide the plant's energy by gearboxes built.

## Material

- Cast iron or aluminium housing.
- Alloy steel gears and shafts.
- Bearings, seals and lubricating oil.

## Process

- Machining housings.
- Gear hobbing, heat treatment and grinding.
- Assembly and run testing.

## Per unit

Report per gearbox by type and weight. A large gearbox can weigh many times a small one, so weight-based allocation of plant energy is usually fairer than a plain count.

## Worked example: plant energy per unit (one month)

- Electricity: 150,000 kWh x 0.710 = 106,500 kg CO2
- PNG: 5,000 SCM x 2.05 = 10,250 kg CO2
- Gearboxes built: 2,000
- Plant total: 116,750 / 2,000 = 58.4 kg CO2 per unit
- Add housing, gears, bearings and oil 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](https://senseible.earth/calculators/product-carbon-footprint)
- [Foundry footprint](https://senseible.earth/answers/foundry-charge-mix-pig-iron-vs-scrap-carbon)
- [Ball bearing footprint](https://senseible.earth/answers/ball-bearing-carbon-footprint-per-bearing)
- [Electric motor footprint](https://senseible.earth/answers/electric-motor-carbon-footprint-per-unit)
- [Automobile industry](https://senseible.earth/industries/automobile)

Sources: [GHG Protocol Product Standard](https://ghgprotocol.org/standards), [ISO 14067:2018, Carbon footprint of products (iso.org)](https://www.iso.org), [IPCC 2006 Guidelines, Volume 2 Energy (fuel defaults)](https://www.ipcc-nggip.iges.or.jp/public/2006gl/vol2.html), [CEA CO2 Baseline Database, version 21.0](https://cea.nic.in/cdm-co2-baseline-database/?lang=en)

Last reviewed 2026-10-21.