How much CO2 does a continuous casting machine with hot charging save a rerolling mill?
In TERI's June 2026 Raipur case, a mill rolling about 15,000 t a year replaced ingot casting and a coal fired reheating furnace with a 10 t an hour continuous caster feeding hot billets to the mill. Its 1,500 t of coal a year went, and TERI put the cut at 3,180 t CO2 a year.
The old route and the new
- Before: two induction furnaces poured ingots by bottom pouring. The hot ingots cooled to room temperature, then went into a coal fired furnace to be heated again for rolling.
- After: a 10 t an hour continuous casting machine makes billets that go hot, straight to the rolling mill. No reheating furnace.
- Output: about 15,000 t of rolled products a year, before and after.
- Coal before: 1,500 t a year, 100 kg per tonne rolled. After: none for reheating.
- Saving about Rs 150 lakh a year on Rs 400 lakh: payback just over 2.5 years.
Why the payback holds
Cooling an ingot to room temperature and heating it again for rolling throws away the heat the induction furnace put in. Hot charging keeps that heat in the steel. The coal saving is the whole reheating fuel bill, not a slice of it, which is why the payback holds even at Rs 4 crore of capital.
What it does to your CBAM figure
Bars, angles and sections are CBAM goods, and reheating coal is a direct emission of the mill. Removing it removes that part of each tonne's embedded emissions: at Senseible's coal factor, about 176 kg per tonne. The melt shop's electricity stays outside CBAM's count for iron and steel, so most of what remains comes from your inputs, such as sponge iron.
Records to keep through the change
- Twelve months of coal invoices and weighbridge slips for the reheating furnace before.
- Production register by product, before and after.
- Furnace and caster kWh, metered separately if you can, since a caster and its cooling add some power.
- The date the reheating furnace was taken out of use.
The Raipur caster, CO2 a year (estimate)
- Coal removed: 1,500 t x 1.76 kg per kg = 2,640 t CO2 at Senseible's Indian coal factor
- TERI reported 3,180 t; the newsletter does not show the factors behind it
- Per tonne rolled: 2,640 / 15,000 = 176 kg CO2 less, all of it direct
Case data from the SAMEEEKSHA newsletter, June 2026 (TERI). The unit is not named in the source. Indian coal 1.76 kg CO2 per kg.
What Senseible does here
Senseible reads coal invoices and power bills into CO2 per tonne rolled, with the direct coal line kept apart for CBAM, so the before and after is ready for a buyer or a green loan.
Sources: SAMEEEKSHA newsletter, June 2026: secondary steel case studies (TERI).pdf), Regulation (EU) 2023/956 establishing CBAM, consolidated
Last reviewed 2026-11-01.