Coking coal: Emissions
The carbon cost of steel's oldest recipe
The carbon cost of steel's oldest recipe What this tab covers The greenhouse-gas footprint of the commodity at a global level, split by lifecycle phase: extraction (or farming), refining and processing, movement, usage, and recycling or end of life. Intensities are per unit of product; the global total combines intensity with world output. Also covers other environmental impacts and the main levers to cut emissions. Emission intensity 3.20 t CO2e per t range 2.8-3.6 · cradle-to-grave; carbon in coal is oxidised in coke ovens, blast furnace and gas use; mine methane at 100-year GWP Global emissions per year 3,400 Mt CO2e per year 2024 · intensity x 1,050 Mt of coking coal outputPer t of coking coal mined, made into coke and used in a blast furnace (cradle-to-grave). Intensity: Derived from carbon content (about 80-85% C) and IEA 2012 and Smil 2016 process data (indicative). Global total: Derived from World Mining Data 2026 (indicative).
Share of footprint by lifecycle phase
Extraction 8% Refining / processing 15% Movement 1% Usage 76%Footprint by lifecycle phase
| Phase | Intensity | Share | Main sources of emissions | Notes | Source |
|---|---|---|---|---|---|
| Extraction | about 0.25 t CO2e/t (range 0.1-0.5) | 8% | methane from deep, gassy seams; diesel and power | Underground longwall mines in Queensland, Kuzbass and Shanxi are gassier than thermal open-cut mines | IEA Global Methane Tracker 2025 (indicative) |
| Refining / processing | about 0.5 t CO2e/t (washing plus coke making) | 15% | coke oven heating; washing circuits | Coke making emits about 285 kg CO2 per t of steel in modern plants | Smil 2016, Still the Iron Age, citing IEA 2012 |
| Movement | about 0.02-0.04 t CO2e/t | 1% | rail to port and Capesize or Panamax shipping | Queensland to India is a long voyage but bulk shipping is efficient | IMO Fourth GHG Study 2020 (indicative) |
| Usage | about 2.4 t CO2/t (reduction of iron ore in the blast furnace and burning of blast furnace gas) | 76% | carbon reacts with iron ore to give CO and CO2 | Integrated steel emits about 1.8-2.0 t CO2/t in the West and up to 3.5 t in India | Smil 2016, Still the Iron Age |
| Recycling / end of life | not applicable; coal cannot be recycled, but scrap-based steel avoids it | – | EAF steel uses scrap and electricity | Scrap-based EAF steel emits about 0.5 t CO2/t versus 2.0 t for integrated mills | Smil 2016; EU CRM 2023 (0% recycling input) |
Other environmental impacts
Coke ovens emit particles, sulphur oxides, ammonia and polycyclic aromatic hydrocarbons: uncontrolled, up to 7 kg of particulates and 6 kg of sulphur oxides per tonne of coke (Smil 2016). Mines in the Jharia field in Jharkhand have burned for a century.
Levers to cut emissions
- More scrap-based EAF steel, which cuts CO2 per tonne by about three quarters (Smil 2016)
- Gas- or hydrogen-based direct reduced iron in place of blast furnaces
- Pulverised coal injection, top-gas recycling and higher furnace efficiency to cut coke rates
- Coal mine methane drainage and capture
- Carbon capture on blast furnace gas
India
Indian integrated steel plants can emit up to 3.5 t CO2 per t of steel and coal-based DRI up to 3.3 t, against about 1.8-2.0 t in the West, partly because of high-ash coal and smaller furnaces (Smil 2016).
Emission figures are indicative global averages from the life-cycle studies named; actual footprints vary widely by site, energy mix and method.