DG Set Diesel Emissions: Scope 1 from Generator Fuel in India

Power cuts make diesel generators (DG sets) part of almost every Indian factory, warehouse and office park. Their fuel is often the largest Scope 1 source for a company without a boiler or a vehicle fleet, and it is one of the first numbers an assurance provider samples in a BRSR filing. This guide covers how to count the litres, which factor to apply, and what evidence to keep.

Why DG set diesel is Scope 1

Under the GHG Protocol, Scope 1 covers direct emissions from sources a company owns or controls. When your company runs the generator and buys its diesel, the combustion is yours, whether the set is owned or rented. In a BRSR it is reported within total Scope 1 emissions, the first parameter of the BRSR Core greenhouse-gas footprint.

The emission factor

The CO2 part follows the IPCC 2006 default for gas/diesel oil, 74,100 kg CO2 per terajoule at a net calorific value of 43.0 TJ per gigagram. At a typical density of about 0.84 kg per litre, that is about 2.68 kg CO2 per litre. Methane and nitrous oxide add a little at their 100-year global warming potentials.

Count litres burned, not litres bought

Diesel is stored before it is burned. A tanker delivered on 30 March may be burned in April, which is the next financial year. Use the stock register for each tank:

• Purchase invoices from the oil company or dealer, with the litres delivered and the delivery date.
• Stock register or dip logs for each tank, with readings at least at month end.
• Run-hour meter logs for each set. Hours multiplied by the manufacturer's consumption at your typical load give a rough cross-check: a large gap points to a leak, theft or a recording error.
• Transfers: diesel moved from the DG tank to vehicles or a boiler belongs to those sources, not the generator.

Worked example

A plant opens the year with 1,500 litres in its DG tank, receives 12,000 litres in deliveries and closes the year with 1,500 litres. It burned 12,000 litres. Scope 1 from the DG set is 12,000 × 2.688 = 32,255 kg CO2e, or 32.3 tonnes.

Three common mistakes

1. Using purchases alone. A year-end delivery inflates one year and deflates the next. Always reconcile against stock.
2. Counting the landlord's generator. If a landlord or mall runs the DG set and bills you per kWh, that is purchased energy and belongs in Scope 2. Ask for the litres they burned and the units they generated so the factor reflects diesel generation, not the grid.
3. Double counting with electricity. kWh from your own DG set are not purchased electricity. Do not add them to Scope 2 at the grid factor; the emissions are already in Scope 1 through the diesel.

What an assurance provider checks

For Scope 1 from diesel, assurers typically sample purchase invoices against the stock register, check that the dip readings close each period, and re-perform the calculation from litres and the stated factor. Keep the invoice, the register page and the factor edition together for every figure.

ZeroCarbon reads HSD invoices into draft Scope 1 entries, applies the published diesel factor with its source shown, and links each figure to the invoice it came from, so the trail an assurer follows is already in place.