How much CO2 does using more cullet save in a glass furnace?

Cullet saves in two ways. It replaces soda ash and limestone, so their process CO2 is never released. It also melts with less energy, so furnace fuel falls. Measure both: carbonates charged and fuel per tonne of glass, before and after.

Track

• Tonnes of cullet, soda ash and limestone charged.
• Furnace fuel per tonne of glass pulled.
• Bought cullet, with the supplier's invoices.

Process CO2 avoided

Soda ash releases 0.415 t CO2 per tonne and limestone 0.440 t CO2 per tonne. Less of each in the batch means less process CO2.

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.

• Firozabad batch carbonates
• Glass container furnace

Sources: IPCC 2006 Guidelines for National Greenhouse Gas Inventories, GHG Protocol Corporate Standard

Last reviewed 2026-10-22.