Which fuel emission factor do I use in Scope 3: combustion only or life cycle?

Life cycle, wherever you have one. The GHG Protocol Scope 3 guidance says fuel and energy used in your value chain take life cycle factors, which add extraction, processing and transport to burning. Combustion factors stay in Scope 1 and 2. Category 3 is the exception: upstream only, combustion left out.

Which factor goes where

• Scope 1, fuel you burn: combustion factor.
• Scope 2, electricity you buy: the grid factor, which counts burning at the power plant.
• Scope 3 Category 3, the upstream of that same fuel and electricity: extraction, refining and transport only, without combustion.
• Other Scope 3 lines that involve fuel, such as a transporter's diesel or a taxi on a business trip: life cycle, combustion plus upstream.

Why Category 3 is the odd one

Combustion of your own fuel and electricity is already in Scope 1 and 2. Adding it again in Category 3 would count it twice, so Category 3 takes only the part before the fuel reaches you. A transporter's diesel appears nowhere else in your inventory, so it takes the full life cycle.

Goods are different

For things you buy, in Category 1 and Category 2, the guidance uses cradle-to-gate factors: everything up to the point the producer sells. A full life cycle factor for a material, running to its disposal, is not used there.

If you only have a combustion factor

For transport, the guidance asks at minimum for combustion and, where possible, the fuel's upstream. A combustion-only figure is acceptable if you say so. Pick upstream factors from internationally recognised, government or peer-reviewed sources, name the source and year, and use the same one each year.

Worked example: 2,933 litres of diesel, two owners

• Combustion: 2,933 x 2.645 = 7,757.8 kg CO2
• Upstream: 2,933 x 0.60 = 1,759.8 kg CO2e
• Burnt by your transporter (Category 4): 7,757.8 + 1,759.8 = 9,517.6 kg
• Burnt in your own generator: 7,757.8 kg in Scope 1, and 1,759.8 kg in Category 3

The upstream factor of 0.60 kg CO2e per litre is an example figure, not a published value. Use the factor from the source you name.

What Senseible does here

Senseible applies combustion factors to fuels in Scope 1 and the CEA grid factor to electricity in Scope 2, and keeps Scope 3 lines in a separate supplier evidence trail. The calculators show the arithmetic so the factor choice stays visible.

• Emission calculators
• Well-to-tank emissions from diesel and LPG
• Freight bills in rupees to litres
• Using UK DESNZ factors in India

Sources: GHG Protocol, Technical Guidance for Calculating Scope 3 Emissions, Introduction (material and energy emission factors; collecting secondary data), GHG Protocol, Technical Guidance for Calculating Scope 3 Emissions, Category 4 (emission factors needed)

Last reviewed 2026-10-31.