# How do I calculate the carbon footprint of a rotomoulded plastic water tank?

Canonical: https://senseible.earth/answers/plastic-water-tank-carbon-footprint-per-unit

Multiply the LLDPE powder used per tank, including flash and rejects, by a resin factor. Add the rotomoulding oven's LPG, PNG or diesel, pulverising and cooling electricity, and fittings. Divide by tanks dispatched, and report each capacity separately since weight scales with litres.

## Material

- LLDPE or MDPE powder: the largest share. A 1,000 litre tank uses many kilograms of polymer; weigh the charge per mould.
- UV stabiliser and carbon black or colour masterbatch.
- Brass or plastic fittings, lids and lids' threads.

## Process energy

- Oven burners: LPG, PNG or diesel, usually the largest plant energy line.
- Pulveriser electricity if you grind your own powder from granules.
- Cooling fans and arm drives.

## Per tank

Allocate oven fuel by cycle time or by charge weight per mould, since a 2,000 litre tank occupies the oven longer than a 500 litre one.

## Worked example: tank plant per tank (one month)

- Oven LPG: 12,000 kg x 2.98 = 35,760 kg CO2
- Electricity: 20,000 kWh x 0.710 = 14,200 kg CO2
- Tanks made: 3,000
- Plant total: 49,960 / 3,000 = 16.65 kg CO2 per tank
- Add LLDPE powder and fittings 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)
- [Emission factors for PP, HDPE and PVC resin](https://senseible.earth/answers/polymer-resin-emission-factors-pp-hdpe-pvc)
- [Recycled content in a product footprint](https://senseible.earth/answers/how-to-count-recycled-content-in-product-footprint)

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 2026-10-20.