# How do I calculate emissions from Indian coal when my bill shows grade or GCV, not tonnes of standard coal?

Canonical: https://senseible.earth/answers/indian-coal-emissions-by-gcv

Convert the coal's calorific value into energy, then multiply by an IPCC CO2 factor per terajoule. Take GCV from the lab report or the grade's band, convert kcal/kg to MJ/kg, reduce GCV to NCV, and apply the IPCC default for the coal type, such as 94.6 t CO2 per TJ for other bituminous coal.

## The formula

1. GCV in MJ/kg = GCV in kcal/kg x 4.1868 / 1,000.
2. NCV = GCV x 0.95. The IPCC notes that for coal NCV is about 5% below GCV; for wet, high-ash coal the gap can be larger, so use a lab NCV if you have one.
3. Energy in TJ = tonnes of coal x NCV in MJ/kg / 1,000.
4. CO2 in tonnes = energy in TJ x the IPCC default factor: 94.6 t CO2 per TJ for other bituminous coal, 96.1 for sub-bituminous.

## Reading the grade on an Indian coal invoice

Under the Ministry of Coal's GCV grading, non-coking coal in India is graded by GCV in bands of 300 kcal/kg, from G1 above 7,000 down to G17 at 2,201 to 2,500. If you only have the grade, use the midpoint of its band and say so. A lab report of the GCV for each consignment is better, because the grade is measured on a standardised basis and the coal you actually burn may be wetter.

## Why calorific value matters

Coal is sold by weight, but its carbon content follows its energy content. Indian non-coking coal is often high in ash, so a kilogram of a low grade holds less energy, and less carbon, than a kilogram of high-grade or imported coal. Working from GCV keeps each consignment's figure tied to the coal you actually burned, which is what an auditor or buyer will check against the lab reports.

## What to keep as evidence

- Purchase invoices or weighbridge slips with tonnes received.
- The supplier's or a third-party lab's GCV report for each consignment, with its moisture basis.
- Stock at the start and end of the year, so you count coal burned, not coal bought.

## Worked example: 20 tonnes of G11 coal

- G11 band 4,001 to 4,300 kcal/kg; midpoint about 4,150 kcal/kg GCV
- GCV: 4,150 x 4.1868 / 1,000 = 17.375 MJ/kg; NCV: 17.375 x 0.95 = 16.506 MJ/kg
- Energy: 20 x 16.506 / 1,000 = 0.330 TJ
- CO2: 0.330 x 94.6 = 31.2 t CO2, or 1.56 kg CO2 per kg of coal

An estimate from the grade midpoint and the IPCC rule that coal NCV is about 5% below GCV. A lab NCV, or the sub-bituminous factor (96.1 t CO2 per TJ), would shift it by a few percent.

## What Senseible does here

Senseible reads tonnes or kilograms from coal invoices and applies the IPCC 2006 default of 2.42 kg CO2 per kg. It does not read the grade or GCV from the bill yet, so if you hold lab GCV reports, keep this calculation and the reports with your records.

- [Coal emission factor](https://senseible.earth/emission-factors/coal)
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- [Scope 1 emissions in Indian manufacturing](https://senseible.earth/climate-intelligence/manufacturing-scope-1-emissions-india)

Sources: [2006 IPCC Guidelines, Vol. 2 Energy, Ch. 1, Tables 1.2 (NCV) and 1.4 (CO2 per TJ)](https://www.ipcc-nggip.iges.or.jp/public/2006gl/vol2.html), [CEA CO2 Baseline Database for the Indian Power Sector, User Guide](https://cea.nic.in/cdm-co2-baseline-database/?lang=en)

Last reviewed 2026-10-15. Grade bands follow the Ministry of Coal GCV grading of non-coking coal; the worked figures are estimates from the band midpoint.