How does a copper smelter split its emissions between cathode and the sulphuric acid it sells?
Sulphuric acid is made from the sulphur dioxide in smelter gas, so it is a co-product. Most smelters allocate shared emissions by mass or economic value and say which, while the acid plant's own energy goes to acid. Buyers of cathode and acid should each get a figure with the method stated.
What is shared
- Concentrate drying, smelting and converting fuel and power.
- Oxygen plant electricity.
- Gas cleaning ahead of the acid plant.
What belongs to acid
The acid plant's blowers and pumps, less any steam it exports. Acid plants often make surplus heat, which some smelters credit.
Is any of this CBAM?
No. Copper and sulphuric acid are outside CBAM's current goods list, so these are product footprint figures for buyers, not customs data.
What Senseible does here
Senseible reads fuel, electricity and freight invoices into a dated, fingerprinted record per site, so a copper product figure can be traced back to the documents behind it. Factors outside India are entered from the official source and labelled.
Sources: ISO 14067:2018 Carbon footprint of products (iso.org), IPCC 2006 Guidelines for National Greenhouse Gas Inventories, GHG Protocol Corporate Standard
Last reviewed 2026-10-21.