# How much CO2 does making plaster of Paris emit per tonne?

Canonical: https://senseible.earth/answers/plaster-of-paris-calcination-co2-per-tonne

Heating gypsum drives off water to make plaster of Paris; that releases no process CO2, unlike limestone. The CO2 comes from the fuel that heats the calciner and from grinding electricity. Divide both by tonnes of plaster produced.

## Records

- Calciner fuel: coal, pet coke, biomass or gas, at IPCC defaults.
- Grinding and bagging electricity.
- Tonnes produced.

## Phosphogypsum

Some plants use gypsum from fertiliser plants. Treat it as a by product with its own allocation, and say so.

## 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.

- [Gypsum board footprint](https://senseible.earth/answers/gypsum-board-carbon-footprint-per-sq-m)
- [Limestone calcination CO2](https://senseible.earth/answers/process-co2-from-limestone-calcination)

Sources: [IPCC 2006 Guidelines](https://www.ipcc-nggip.iges.or.jp/public/2006gl/), [CEA CO2 Baseline Database](https://cea.nic.in/cdm-co2-baseline-database/?lang=en)

Last reviewed 2026-10-22.