How much CO2 does a naphtha steam cracker emit per tonne of ethylene?
IPCC Tier 1 defaults put a naphtha cracker at about 1.73 tonnes of CO2 per tonne of ethylene and an ethane cracker at about 0.95, mostly from furnace fuel. A real plant should use its own fuel gas meters and analysis, since furnace efficiency and fuel mix move the figure a lot.
Where it comes from
- Cracking furnaces burning the plant's own methane rich fuel gas, often the largest share.
- Decoking and flaring.
- Steam and power from captive plants.
Measured beats default
Use metered fuel gas with its composition, as for any refinery gas, and add bought power and steam. The IPCC defaults are only for checking or when nothing is measured.
Sharing it across products
A cracker makes ethylene, propylene, butadiene and pyrolysis gasoline together. Split emissions by mass or energy, say which, and use the same rule every year.
What Senseible does here
Senseible reads fuel, electricity and freight invoices into a dated, fingerprinted record per site, so each figure you send a buyer can be traced back to the documents behind it.
Sources: IPCC 2006 Guidelines, Volume 3 Industrial Processes, GHG Protocol Product Standard
Last reviewed 2026-10-21.