The Chennai aluminium die casting profile lists four savings in tonnes of oil equivalent. What are they in tonnes of carbon dioxide (CO2) on today's factors?

The profile's four measures total 2,700 tonnes of oil equivalent (toe) a year, 21.9% of the cluster's 12,340. On the 2025-26 grid factor and a diesel factor that is about 19,500 tonnes of CO2 a year, 23.6% of about 82,700. The measures overlap, so do not simply add them.

The four measures as printed

• Better electric resistance furnaces: from 530 to 550 kilowatt hours (kWh) a tonne to as low as 400, "about 25%", payback 3 to 4 years. Cluster saving 12 million kWh, about 1,000 toe.
• A lid system on furnace openings at 400 to 600 degrees C: cuts opening heat loss by about 40%. About 600 toe.
• Heat recovery on diesel-fired bulk melting furnaces, where flue gas takes almost 50% of heat input: about 15% better thermal efficiency, payback under one year. 400 toe.
• Servo pumps in place of hydraulics on pressure die casting (PDC) machines: at least 30% saving. 700 toe.
• Total 1,000 + 600 + 400 + 700 = 2,700 toe, which is 21.9% of 12,340.

Into tonnes of CO2

• Furnaces: 12 million kWh x 0.675 kg = 8,100 tonnes.
• Lid: 600 toe. The profile's own ratio is 110 million kWh for 9,426 toe, or 11,670 kWh a toe, so 7.00 million kWh x 0.675 = 4,726 tonnes.
• Servo pumps: 700 toe is 8.17 million kWh, 5,514 tonnes.
• Heat recovery: I assume the 400 toe is diesel, since the furnaces burn it. The profile's ratio is 2,914 toe for 3,200 kilolitres (kL), so 400 toe is 439 kL, and 439,000 litres x 2.645 kg = 1,162 tonnes.
• Sum: 8,100 + 4,726 + 5,514 + 1,162 = 19,502 tonnes.
• The cluster baseline on the same factors: 110 million kWh x 0.675 = 74,250 tonnes, plus 3,200,000 litres x 2.645 = 8,464 tonnes, 82,714 tonnes. The four measures are 23.6% of it.

Where it does not add neatly

• Overlap. A better furnace and a lid both cut heat lost from the same furnace, so adding them may count some kWh twice. The profile gives no overlap figure.
• The 12 million kWh is 25% of 48 million kWh, which is 44% of the cluster's 110 million. The profile says melting and holding take about 60% of a unit's energy. It does not say which base the 25% was taken on.
• The lid measure is headed "induction furnace" but its text describes the electric furnaces with top openings. I read the heading as a slip.
• The profile dates its cluster table 2014-15 and does not say what year the savings are taken against. The grid factor has moved since, so the CO2 per kWh saved is not the same every year.

What to take from it

Furnace efficiency is the largest block, then servo pumps. A single unit gains only from the measures it does not already have. Pick the one that matches your meter: if furnaces take 60% of your electricity, start there.

A 1,200 tonne unit using 1,445,000 kWh

• Furnaces take about 60% of the energy: about 867,000 kWh
• A 25% saving on that: about 217,000 kWh, about 146 t of CO2 at 0.675
• Servo pumps at 30% of the pressure die casting share, taken as 20%: 1,445,000 x 20% x 30% = 86,700 kWh, about 59 t

The 60% and 20% shares are the profile's figures for a unit's energy, applied here to one example unit, so this is an example, not a quote. Overlap between measures is not removed.

What Senseible does here

Senseible reads fuel invoices and electricity bills into monthly records, so you have your own litres and kilowatt hours to hold against the profile's. It does not check a published report for you.

• Chennai die casters: energy and Carbon Border Adjustment Mechanism (CBAM)
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• Aluminium scrap melting fuel per tonne
• Green loan readiness check

Sources: The Energy and Resources Institute (TERI), Cluster profile: Chennai aluminium casting industries (SAMEEEKSHA), Central Electricity Authority (CEA), CO2 Baseline Database

Last reviewed 2026-11-05. Savings are the profile's estimates for 2014-15. The tonnes of CO2 are my conversion with the profile's own toe ratios; the diesel assumption for heat recovery and the overlap are flagged above. Confirm with a quote and your own meter.