# What do Coimbatore foundries use per tonne of castings, and how does one unit compare with the cluster?

Canonical: https://senseible.earth/answers/coimbatore-foundry-cluster-energy-per-tonne-castings

Between 1,000 and 1,200 kWh per tonne of good castings, 600 to 700 of it in melting, is what TERI measured in Coimbatore's induction foundries. A 1,000 tonne a year unit uses about 1.1 million kWh, about 743 t CO2. Above 1,200, look at your furnace and your rejections first.

## The cluster you are measured against

- About 535 foundries: about 15 large, 70 medium, the rest small and micro, making about 2,000 tonnes a day (about 0.6 million tonnes a year).
- Half make pump-set castings. The rest serve automotive (15%), wet grinders (10%), textile machinery (10%) and jobbing work (15%).
- In 2014 to 15 the cluster used 460 million kWh and 32,000 tonnes of coke, 58,640 tonnes of oil equivalent. That is about 407,000 tonnes of CO2 on today's factors.
- Power comes from the state utility or from wind farms in Tamil Nadu.

## Check your own number

1. Add 12 months of kWh from your bills and divide by tonnes of good castings despatched.
2. Compare with 1,000 to 1,200 kWh a tonne. If you have a sub-meter, compare melting alone with 600 to 700 kWh per tonne of molten metal.
3. For a cupola, coke should be 10% to 15% of metal melted, or 15% to 20% of good castings.
4. If you are high, check rejections (many units run at 6% to 9%), furnace age and whether the furnace has a lid.

## Where the savings are

- An old induction furnace at 750 kWh or more per tonne of molten metal can be replaced with one near 550. TERI puts the payback under a year.
- A lid cuts radiation and convection loss, 4% to 6% of input energy.
- Bringing rejections below 5%, and shot blasting the sand off runners and risers before remelting, saves melting energy for little or no cost.
- Wind power bought under contract cuts market-based Scope 2, if you keep the supply records.

## Why pump makers will ask you

Pump and motor makers who export are starting to ask their foundries for kg CO2 per tonne, because their own buyers want a product footprint. A green loan for a new furnace is easier to get with kWh per tonne before and after from bills.

## Worked example: a 1,000 tonne a year induction foundry

- Electricity: 1,100,000 kWh x 0.675 = 742.5 t CO2, about 0.18% of the cluster's 407,000 t
- Per tonne of good castings: 742.5 / 1,000 = 0.74 t CO2
- New furnace, 750 down to 550 kWh per tonne of molten metal, on 1,400 t melted: 200 x 1,400 = 280,000 kWh saved
- CO2 saved: 280,000 x 0.675 = 189 t a year

Unit energy is from TERI's Coimbatore profile. 1,400 t melted assumes about 70% yield; use your own melt log. Grid factor for FY 2025-26; coke in the cluster total at 3.02 t CO2 per tonne (IPCC default).

## What Senseible does here

Senseible reads your electricity bills and coke invoices into a monthly record, and the green loan check shows what a lender will look for before you apply for a furnace upgrade.

- [Green loan readiness check](https://senseible.earth/green-loan-check)
- [Coimbatore induction foundry: CBAM vs footprint](https://senseible.earth/answers/coimbatore-induction-foundry-cbam-vs-footprint)
- [Coimbatore pump exporter EPD for buyers](https://senseible.earth/answers/coimbatore-pump-exporter-epd-for-buyers)
- [Foundry footprint per good casting](https://senseible.earth/answers/foundry-carbon-footprint-per-tonne-good-casting)

Sources: [TERI, Cluster profile: Coimbatore foundries (SAMEEEKSHA)](https://sameeeksha.org/pdf/clusterprofile/coimbatore-foundry-cluster.pdf), [IPCC 2006 Guidelines, Volume 2 Energy](https://www.ipcc-nggip.iges.or.jp/public/2006gl/vol2.html), [CEA CO2 Baseline Database, version 22.0](https://cea.nic.in/cdm-co2-baseline-view?mappingId=234&lang=en)

Last reviewed 2026-10-29. Cluster energy is for 2014 to 15. Update if a newer Coimbatore profile is published.