How to Calculate CO2 Emissions From Diesel and HVO100

Customers, banks and larger business partners increasingly ask fleet operators for a fuel-emissions figure they can put in a report. Most online CO2 calculators return a number without showing the method, and supplier claims such as "up to 86% lower emissions" are hard to translate into your own tonnes. This guide shows how to calculate CO2 emissions from diesel step by step, what changes when you switch to HVO100, and which values to use so the result holds up when someone checks it.

Key Takeaways: To calculate CO2 emissions from fuel, convert litres to energy, multiply by the fossil fuel baseline of 94.1 gCO2e/MJ and convert to tonnes – then apply the fuel's greenhouse gas saving. For a 20-truck fleet using 600,000 litres of HVO100 a year, the fossil equivalent is about 1,920 tonnes CO2e; at the 86%* saving used in our calculator's example, HVO100's lifecycle emissions are about 269 tonnes. For a quick estimate, use the CO2 calculator on our HVO100 page; for your report, use the actual saving stated on your Proof of Sustainability.

The Formula in One Line

This is the formula behind the CO2 calculator on our HVO100 page:

Litres ÷ 1,000 × GJ/m³ × 1,000 × 94.1 gCO2e/MJ ÷ 1,000,000 = GHG baseline (tonnes CO2e) GHG baseline × GHG emission saving (%) = GHG emission saving (tonnes CO2e)

In words: convert litres to cubic metres, multiply by the fuel's energy content to get energy, multiply by the fossil fuel baseline to get what that energy would have emitted as fossil fuel – and then apply the fuel's greenhouse gas saving.

Energy, not volume, is the right unit because that is how EU law, sustainability certificates and national emission-factor tables all express greenhouse gas intensity. The 94.1 gCO2e/MJ is the EU's fuel baseline standard for fossil fuels (Council Directive (EU) 2015/652, Annex II). The saving percentages on Proof of Sustainability documents are calculated under the Renewable Energy Directive, which compares a renewable fuel's lifecycle emissions (E) with a fossil fuel comparator of 94 gCO2e/MJ: saving = (94 – E) ÷ 94 (Directive (EU) 2018/2001, consolidated text, Annex V, Part C, points 3 and 19). Applying such a saving to the 94.1 baseline changes the result by around 0.1% – too little to matter in practice.

The four steps below fill in each part of the formula.

Step 1 – Convert Litres to Energy

Each fuel has its own energy content. Use it to turn litres into energy before anything else. The values our calculator uses:

Sources: Directive (EU) 2018/2001, consolidated text, Annex III; Drivkraft Sverige, "Energiinnehåll, densitet och koldioxidemission, TTW och WTW" (2025).

Example: 600,000 litres of HVO100 ÷ 1,000 = 600 m³ × 34 GJ/m³ = 20,400 GJ (20.4 TJ).

A practical note: because a litre of HVO100 carries slightly less energy than a litre of B7 diesel (34 against 35 MJ), the same work typically takes around 3% more litres. Keep that in mind when you estimate future volumes from today's diesel consumption.

Step 2 – Calculate the Fossil Baseline

Multiply the energy by the fossil fuel baseline of 94.1 gCO2e/MJ. That gives the lifecycle emissions the same energy would have caused as fossil fuel – roughly 3.2–3.4 kg CO2e per litre of diesel. At the tailpipe alone, diesel emits about 2.5–2.7 kg CO2 per litre. Which figure you use depends on the boundary you report:

• Well-to-tank (WTT): emissions from extracting, refining and transporting the fuel.
• Tank-to-wheel (TTW): emissions from burning the fuel in the engine.
• Well-to-wheel (WTW): both together – the lifecycle view used by RED III and by Proof of Sustainability documents.

Published reference values for diesel:

Sources: Council Directive (EU) 2015/652, Annex II; RED Annex V; Drivkraft Sverige, "Energiinnehåll, densitet och koldioxidemission, TTW och WTW" (2025); Energistyrelsen, "Standardfaktorer for brændværdier og CO2-emissionsfaktorer", reporting year 2024 (published for EU ETS installations).

For the worked example: 20,400 GJ × 1,000 × 94.1 gCO2e/MJ ÷ 1,000,000 = 1,920 tonnes CO2e – the GHG baseline for 600,000 litres of HVO100.

For comparison, our calculator works out the same 600,000 litres of diesel B7 like this: 600 m³ × 35 GJ/m³ × 94.1 gCO2e/MJ = 1,976 tonnes, minus the saving from its biodiesel share. The calculator treats B7 as 7% biodiesel with a 67% saving, so 7% × 67% = 4.69%, which gives about 1,883 tonnes CO2e a year on diesel B7.

Step 3 – Find the Right HVO100 Value

For a quick estimate, use our calculator – an illustrative example that applies Biofuel Express's 2025 headline saving of 86%* for HVO100. For your emissions report, use the actual saving stated on your Proof of Sustainability (PoS). Fall back on the EU default value only when no actual value is available.

RED III recognises three kinds of value:

• Actual value: calculated for the specific batch with the RED formula and verified under a certification scheme such as ISCC EU. This is what appears on the PoS for your delivery.
• Typical value: an estimate for a representative production pathway.
• Default value: a deliberately conservative figure that may be used instead of calculating the actual value.

The feedstock makes the biggest difference. RED III's typical savings for HVO range from 87% for used cooking oil down to 34% for palm oil produced without methane capture:

How to read the value on a Proof of Sustainability

A PoS under ISCC EU states, among other things, the quantity delivered, its energy content in MJ, the raw material, the total emissions E in gCO2e/MJ and the resulting saving against the 94 gCO2e/MJ comparator. It also confirms that the fuel has not already been used to meet a national quota obligation.

As an example, a public ISCC EU PoS for HVO made from used cooking oil lists 24.058 m³ with an energy content of 817,971 MJ (34 MJ per litre), total emissions of 6.24 gCO2e/MJ and a saving of 93.4% (ISCC EU PoS V3.0, published by the Irish EPA). Those three numbers – energy, E and saving – are all you need for the calculation. Read more about what a Proof of Sustainability is and how to check that your PoS is valid.

Step 4 – Worked Example: a 20-Truck Fleet

A fleet using 600,000 litres of HVO100 a year has a GHG baseline of about 1,920 tonnes CO2e. At the 86%* saving used in our calculator's example, its lifecycle emissions are about 269 tonnes – and in the examples below, anywhere from about 127 to 1,017 tonnes, depending on the certified batch.

GHG baseline: 600,000 l ÷ 1,000 × 34 GJ/m³ × 1,000 × 94.1 gCO2e/MJ ÷ 1,000,000 = 1,919.6 t CO2e. Savings: Biofuel Express CO2 calculator; ISCC EU PoS example; RED Annex V, Part A. Rounded to whole tonnes.

The lesson: the name on the pump says little on its own. The feedstock and the certified value decide whether your saving is closer to 47% or 93%. That is why a calculator example is fine for a first estimate, but your Proof of Sustainability is what belongs in your report. The Swedish Energy Agency makes the same point about its own HVO100 market average of 16.0 gCO2e/MJ for 2024: figures for individual loads differ by raw material and production method (Drivkraft Sverige 2025).

Why HVO100 Savings Vary – and How They Can Exceed 100%

Savings vary because each batch's emissions depend on its feedstock and production route. They can exceed 100% because the RED formula subtracts certified emission savings, or "credits", from a batch's emissions.

RED III calculates a biofuel's total emissions as:

E = eec + el + ep + etd + eu – esca – eccs – eccr

• eec – extracting or cultivating the raw material
• el – annualised emissions from land-use change
• ep – processing
• etd – transport and distribution
• eu – the fuel in use (set to zero for biofuels)
• esca – savings from soil carbon accumulation through improved agricultural management
• eccs – savings from CO2 capture and geological storage
• eccr – savings from CO2 capture and replacement

Source: Directive (EU) 2018/2001, consolidated text, Annex V, Part C, point 1.

Wastes and residues such as used cooking oil are counted as having zero lifecycle emissions up to the point they are collected (Annex V, Part C, point 18), which is why they score highest. And when the three credit terms are larger than the emission terms, E becomes negative – and a negative E gives a saving above 100%. A saving of 121%, for example, corresponds to E ≈ –19.7 gCO2e/MJ, because (94 + 19.7) ÷ 94 ≈ 1.21.

This is what lies behind the range Biofuel Express reports. Biofuel Express's HVO100 delivers up to 86% lower greenhouse gas emissions compared to fossil diesel*, with individual certified deliveries ranging from 57% to 121%. The upper end of that range comes from batches where certified credits outweigh the emissions from production and transport. For how feedstock sourcing shapes HVO100's footprint, see how sustainable is HVO100?

Scope 1 vs Lifecycle: Reporting HVO100 Correctly

Under the GHG Protocol, CO2 from burning HVO100 is biogenic and is reported separately in a memo item, outside Scope 1, 2 and 3. Methane (CH4) and nitrous oxide (N2O) from combustion still belong in Scope 1, and the upstream emissions of producing the fuel belong in Scope 3 (GHG Protocol, Calculation Tools FAQ).

That creates a common trap. In the worked example:

• Scope 1 view: at the tailpipe, diesel emits about 2.5–2.7 kg fossil CO2 per litre (Drivkraft Sverige; Energistyrelsen). After the switch, fossil CO2 in Scope 1 falls to zero and only the small CH4 and N2O share remains – which looks like a saving of almost 100%.
• Lifecycle view: at the 86%* saving used in the calculator example, lifecycle emissions are about 269 tonnes CO2e against a fossil baseline of about 1,920 tonnes.

Both figures are correct, but they answer different questions. If you report the Scope 1 drop as "our emissions saving", you overstate the benefit and leave the fuel's upstream emissions out of your inventory. Report the Scope 1 change in Scope 1, the upstream emissions in Scope 3, the biogenic CO2 as a memo item – and use the lifecycle figure when you describe the effect of the switch. Our guide to reporting fuel emissions across Scope 1, 2 and 3 explains the full framework, and how CSRD affects companies – large and small covers why customers ask their transport partners for this data.

Five Mistakes That Distort Fuel Emissions Figures

1. Using the wrong energy content. Each fuel has its own energy content – diesel B7 35, HVO100 34 and B100 33 GJ/m³. Applying one fuel's energy content, or a per-litre emission factor, to another fuel skews the result.
2. Presenting the Scope 1 drop as the total saving. As shown above, Scope 1 can fall to almost zero while the lifecycle saving is lower.
3. Mixing boundaries. Comparing a lifecycle (WTW) diesel figure with a tailpipe (TTW) HVO100 figure – or the other way round – gives a meaningless result. Use the same boundary for both fuels.
4. Using an average when you have a batch value – and not saying which you used. A PoS value beats a default, and a default beats a national average. Always state the method, the source and the data year.
5. Double counting. A PoS confirms that the fuel has not already been used to meet a national quota obligation. Do not claim reductions that have been sold on separately, and remember that a CO2 factor of zero for biofuels only applies with documented compliance with the sustainability criteria (Energistyrelsen).

Let the Data Come to You

Doing this calculation by hand for every delivery takes time. Biofuel Express Insight shows CO2e per delivery based on its Proof of Sustainability data, with full traceability and downloadable reports – the method in this guide, applied automatically to your own fuel. Learn more about HVO100 from Biofuel Express or the fuel itself in our complete guide to HVO100, and contact us to see Insight with your own fleet data.

FAQ

How much CO2 does one litre of diesel produce?

At the tailpipe, about 2.5–2.7 kg CO2 per litre: Drivkraft Sverige lists 2.54 kg for Swedish MK1 diesel and 2.66 kg for EN 590 diesel, and the Danish Energy Agency's factors give about 2.66 kg. On a lifecycle basis it is about 3.36 kg CO2e per litre (3,357 g, Drivkraft Sverige).

Does HVO100 produce CO2 when it is burned?

Yes. Burning HVO100 releases CO2, but it is biogenic – it comes from biomass rather than fossil carbon. Under the GHG Protocol, it is reported separately as a memo item rather than in Scope 1, while CH4 and N2O from combustion stay in Scope 1.

Is HVO100 counted in Scope 1 or Scope 3?

Both. CH4 and N2O from combustion are Scope 1, the emissions from producing and transporting the fuel are Scope 3, and the biogenic CO2 is reported separately.

Which saving should I use for HVO100?

For a quick estimate, the example value in our calculator (86%*, the 2025 headline figure). For your emissions report, the actual saving on your Proof of Sustainability. If none is available, use the RED III default value for the feedstock. Always state which value, source and data year you used.

How does the Biofuel Express CO2 calculator work?

It uses the formula in this guide: litres ÷ 1,000 × energy content (GJ/m³) × 1,000 × 94.1 gCO2e/MJ ÷ 1,000,000, multiplied by the fuel's greenhouse gas saving. It uses 35 GJ/m³ and a 4.69% saving for diesel B7, 34 GJ/m³ and 86% for HVO100 (the 2025 headline figure*), and 33 GJ/m³ and 67% for B100. You'll find it on our HVO100 page.

Why does Biofuel Express say "up to 86%"?

Because the saving differs from batch to batch with the feedstock. 86% is the headline figure for 2025, and actual deliveries ranged from 57% to 121%.* The calculator uses the headline figure as an illustrative example, so its result shows a best case rather than your actual saving – your Proof of Sustainability shows the actual saving for your deliveries.

Conclusion

• Turn litres into energy first, using each fuel's own energy content.
• Multiply by the fossil baseline of 94.1 gCO2e/MJ, then apply the fuel's greenhouse gas saving.
• Use our calculator for a quick estimate – and the actual saving on your Proof of Sustainability for your report.
• Report Scope 1, Scope 3 and biogenic CO2 separately – and use the lifecycle figure to describe the effect of switching.

Want the numbers calculated for you? Talk to us about Biofuel Express Insight.

* Based on 2025 verified delivery data. Actual reduction per delivery ranges from 57% to 121% depending on feedstock composition and certified batch. Calculated per the RED III well-to-wheel life-cycle methodology using ISCC-certified mass balance allocation. Proof of Sustainability (PoS) documentation available on request.

Sources

1. Biofuel Express – CO2 calculator on the HVO100 product page: formula and input values (energy contents, 94.1 gCO2e/MJ baseline, HVO100 saving = 2025 headline figure, used as an illustrative example).
2. European Union – Council Directive (EU) 2015/652, Annex II: fuel baseline standard of 94.1 gCO2eq/MJ.
3. European Union – Directive (EU) 2018/2001 on the promotion of the use of energy from renewable sources, consolidated text of 16.07.2024 (incl. RED III amendments): Annex III (energy content), Annex V Part A (typical and default savings), Part C (calculation rules, 94 gCO2e/MJ comparator) and Part D (disaggregated and total values).
4. Drivkraft Sverige – Energiinnehåll, densitet och koldioxidemission, TTW och WTW (2025). Biofuel values from the Swedish Energy Agency's reporting statistics for the 2024 market.
5. Energistyrelsen (Danish Energy Agency) – Standardfaktorer for brændværdier og CO2-emissionsfaktorer til brug for rapporteringsåret 2024.
6. ISCC EU – Proof of Sustainability for Biofuels, Bioliquids and Biomass Fuels V3.0, example document published by the Irish Environmental Protection Agency.
7. GHG Protocol – Calculation Tools FAQ: reporting of CO2, CH4 and N2O from biomass combustion.
8. Biofuel Express – 2025 verified delivery data for HVO100 (see footnote).