3. Fuel emission factors

Fuel can be categorised by its end-use, that is, either stationary combustion or transport. This section also includes biofuels and the transmission and distribution losses for reticulated natural gas.

In line with the reporting requirements of ISO 14064-1:2018 and the GHG Protocol we provide emission factors for direct (Scope 1) sources to allow separate estimation of carbon dioxide, methane and nitrous oxide emissions calculations.

3.1 Overview of changes since previous update

The fuel emission factors are based on data from New Zealand’s Greenhouse Gas Inventory 1990–2022.

Four new biofuel blends were added this year: two bioethanol blends, E3 and E10. The E3 and E10 blends consist of 3 per cent and 10 per cent bioethanol respectively, with the remaining contribution made up of diesel. For the two biodiesel blends, B5 and B20, each consists of 5 per cent and 20 per cent biodiesel respectively, with the remaining contribution made up of diesel.

Five new wood biomass factors were also added; three for use in manufacturing applications and two for use in commercial applications.

The emission factor value for bioethanol decreased by 35 per cent, and the value for biodiesel increased by 54 per cent, because in the previous edition incorrect calorific values were being applied.

3.2 Stationary combustion fuel

Stationary combustion fuels are burnt in a fixed unit or asset, such as a boiler. Direct (Scope 1) emissions occur from the combustion of fuels within equipment owned or controlled by the reporting entity. If the entity does not own or control the assets where combustion takes place, then these emissions are indirect (Scope 3) emissions. For more information see section 1.5.1.

3.2.1 Emissions factors

Table 3.1 contains emission factors for common fuels used for stationary combustion in New Zealand. The Ministry of Business, Innovation and Employment (MBIE) provided the emission factors and supporting data. The same data were used in New Zealand’s Greenhouse Gas Inventory 1990–2022.

Sectors for consumption statistics are based on Australian and New Zealand Standard Industrial Classification (ANZSIC) codes.

Residential use emission factors are for fuel used primarily at residential properties. Commercial use is for fuels used at properties or sites where commercial activities take place. Industrial use emission factors can be applied where combustion takes place at sites where there are industrial processes or within engines that support industrial activities.

Table 3.1: Stationary Combustion Emission Factors

		Unit	CO2	CH4	N2O
Commercial use	Coal - Bituminous	kg	2.6374	0.0079	0.0112
	Coal - Default	kg	2.0590	0.0060	0.0085
	Coal - Lignite	kg	1.4204	0.0041	0.0058
	Coal - Sub-Bituminous	kg	1.9910	0.0058	0.0082
	Natural Gas	kWh	0.1946	0.0005	0.0001
	Natural Gas	GJ	54.0579	0.1260	0.0238
	LPG	kg	2.9637	0.0066	0.0013
	Diesel	litre	2.6638	0.0102	0.0058
Industrial Use	LPG	kg	2.9637	0.0013	0.0013
	Diesel	litre	2.6638	0.0031	0.0058
	Natural Gas	kWh	0.1946	0.0001	0.0001
	Natural Gas	GJ	54.0579	0.0252	0.0238
	Coal - Sub-Bituminous	kg	1.9910	0.0058	0.0082
	Coal - Lignite	kg	1.4204	0.0041	0.0058
	Coal - Default	kg	1.9192	0.0056	0.0079
	Coal - Bituminous	kg	2.6374	0.0079	0.0112
Residential use	Coal - Sub-Bituminous	kg	1.9910	0.1727	0.0082
	Coal - Bituminous	kg	2.6374	0.2361	0.0112
	Coal - Lignite	kg	1.4204	0.1217	0.0058
	Coal - Default	kg	1.9704	0.1714	0.0081

Notes: Commercial and industrial classifications are based on standard classification¹. Use the default coal emission factor if it is not possible to identify the type of coal. Convert LPG-use data in litres to kilograms by multiplying by the specific gravity of 0.534 kg/litre.

3.2.2 How to use the emissions factors

To calculate stationary combustion fuel emissions, first collect data on the quantity of fuel used, and then multiply this by the appropriate emission factor from the table. Applying the equation \(E = Q * F\) (see How To), this means:

E = emissions from the emissions source in kg CO₂-e per year

Q = quantity of fuel used (unit)

F = appropriate emission factors from Table 3.1.

Entities typically report emissions using data on the amount of fuel used during the reporting period.

Example calculation

An entity uses 1,400 kg of LPG to heat an office building in the reporting year:

	Emission Factor (Kg CO2e/Kg)	Calculation	Emissions (Kg CO2e)
Gas
CO2	2.963726	1400.0 x 4149.22	4149.22
CH4	0.006650	1400.0 x 9.31	9.31
N2O	0.001259	1400.0 x 1.76	1.76
Total_CO2e	2.971635	1400.0 x 4160.29	4160.29

Note: Numbers may not add due to rounding.

3.2.3 How the emissions factors were derived

We derived the kg CO₂-e per activity unit emission factors supplied in Table 3.1 using calorific values and emission factors for tonnes of gas per terajoule (tTJ). These are either sourced from the New Zealand’s Greenhouse Gas Inventory 1990–2022 or default emission factors from the IPCC.

To calculate the final emission factors for CO₂, CH₄ and N₂O, the calorific value is multiplied by the emission factor (t/TJ) for each gas type. The CH₄ and N₂O vales are then multiplied by their global warming potentials, 28 and 265 respectively.

The calorific values are in Appendix A: Derivation of fuel emission factors alongside further information on the methodology.

3.2.4 Assumptions, limitations and uncertainties

We derived the kg CO₂-e per activity unit emission factors in Table 3.1 using calorific values, listed in Appendix A: Derivation of fuel emission factors.

For a breakdown of the uncertainty by gas type see the Emission factors workbook.

The emission factors above account for the direct (Scope 1) emissions from fuel combustion. They are not full fuel-cycle emission factors and do not incorporate indirect (Scope 3) emissions associated with the extraction, production and transport of the fuel.

We calculated the default coal emission factors by weighting the emission factors for the different ranks of coal (bituminous, sub-bituminous and lignite) by the amount of coal used for each sector (commercial, residential, industrial). The guide includes emission factors for residential coal for completeness.

3.3 Transport fuel

3.3.1 Emissions factors

Transport fuels are used in an engine to move a vehicle. Table 3.2 lists the emission factors.

Table 3.2: Transport Fuel Emissions Factors

		Unit	CO2	CH4	N2O
Commercial use	Heavy Fuel Oil	litre	3.0366	0.0108	0.0062
Commercial use	Light Fuel Oil	litre	2.9540	0.0108	0.0061
Industrial Use	Heavy Fuel Oil	litre	3.0366	0.0033	0.0062
Industrial Use	Light Fuel Oil	litre	2.9540	0.0032	0.0061
nan	Aviation fuel (Kerosene)	GJ	67.9340	0.0133	0.5035
	Aviation fuel (Kerosene)	litre	2.5000	0.0005	0.0185
	Aviation gas	GJ	65.8915	0.0133	0.5035
	Aviation gas	litre	2.2315	0.0005	0.0171
	Diesel	litre	2.6393	0.0040	0.0374
	Heavy Fuel Oil	litre	3.0366	0.0076	0.0205
	LPG	litre	1.5731	0.0438	0.0013
	Light Fuel Oil	litre	2.9540	0.0075	0.0204
	Premium Petrol	litre	2.3213	0.0308	0.0706
	Regular Petrol	litre	2.2831	0.0304	0.0696

Notes: No estimates are available for marine diesel as Marsden Point oil refinery has stopped making the marine diesel blend. If an entity was using marine diesel, it is now likely to be using light fuel oil; use the corresponding emission factor for light fuel oil instead.

These petrol emission factors may be different from those in the ETS regulations².

3.3.2 How to use the emissions factors

To calculate transport fuel emissions, first collect data on the quantity of fuel, and then multiply this by the appropriate emission factor from the table. Applying the equation E = Q x F (see [Section 2: Quantify emissions])(2_how-to.qmd#Calculating_an_emissions_factor), this means:

E = emissions from the emissions source in kg CO₂-e per year

Q = quantity of fuel used (unit)

F = appropriate emission factors from Table 3.2

All entities across sectors typically report emissions using data on the amount of fuel used during the reporting period. Quantified units of fuel weight or volume (commonly in litres) are preferable. If this information is unavailable see section 3.3.2.

Example calculation

Example calculation of 4000 liters of Regular Petrol used.

	Emission Factor (Kg CO2e/Litre)	Calculation	Emissions (Kg CO2e)
Gas
CO2	2.283122	40000.0 x 91324.88	91324.88
CH4	0.030356	40000.0 x 1214.25	1214.25
N2O	0.069649	40000.0 x 2785.94	2785.94
Total_CO2e	2.383127	40000.0 x 95325.08	95325.08

Note: Numbers may not add due to rounding.

3.3.3 When no fuel data are available

If your records only provide information on kilometres (km) travelled, and you do not have information on fuel use, see section 7: Travel emission factors. Factors such as individual vehicle fuel efficiency and driving efficiency mean that kilometre-based estimates of carbon dioxide equivalent emissions are less accurate than calculating emissions based on fuel-use data. Therefore, only use the emission factors based on distance travelled if information on fuel use is not available.

Calculating transport fuel based on dollars spent is less accurate and should only be applied to taxis. Seesection 7.2

3.3.4 How the emissions factors were derived

We applied the same methodology to the transport fuels that we used to calculate the stationary combustion fuels, using the raw data in Appendix A: Derivation of fuel emission factors. The fuel properties of kerosene and aviation gas are 0.0371 and 0.0339 litres per GJ respectively.

3.3.5 Assumptions, limitations and uncertainties

We derived the kg CO₂-e per activity unit emission factors in Table 3.2 using calorific values. All emission factors incorporate relevant oxidation factors sourced from the ³.

As with the fuels for stationary combustion, these emission factors are not full fuel-cycle emission factors and do not incorporate the indirect (Scope 3) emissions associated with the extraction, production and transport of the fuel.

3.4 Biofuels and biomass

3.4.1 Emissions factors

This section provides emission factors for bioethanol, biodiesel and wood emission sources.

The carbon dioxide emitted from the combustion of biofuels and biomass (including wood) is biogenic, meaning it equates to the carbon dioxide absorbed by the feedstock during its lifespan. This means we treat the carbon dioxide portion of the combustion emissions of biofuels as carbon neutral. However, these CO₂ emissions still need to be reported separately in the inventory, under biogenic emissions. This is why the kg CO₂-e/unit figures in Table 3.3 are the sum of the CH₄ and N₂O.

The combustion of biofuels generates anthropogenic methane and nitrous oxide. Entities should calculate and report these gases as is done at the national level according to the 2006 IPCC Guidelines for National Greenhouse Gas Inventories⁴.

Table 3.3 details the emission conversion factors for the GHG emissions from the combustion of biofuels.

Table 3.3: Biofuels and Biomass Emission Factors

		Unit	CO2	CH4	N2O
Commercial use	Wood - Chips	kg	0.0000	0.1018	0.0128
Commercial use	Wood - Pellets	kg	0.0000	0.1276	0.0161
Manufacturing use	Wood - Chips	kg	0.0000	0.0102	0.0128
	Wood - Green	kg	0.0000	0.0060	0.0075
	Wood - Pellets	kg	0.0000	0.0128	0.0161
nan	Biodiesel	GJ	nan	0.5040	0.9818
	Biodiesel	litre	nan	0.0184	0.0358
	Biodiesel blend B20	litre	2.1114	0.0068	0.0371
	Biodiesel blend B5	litre	2.5073	0.0047	0.0374
	Bioethanol	GJ	nan	0.5040	2.0140
	Bioethanol	litre	nan	0.0119	0.0475
	Bioethanol blend E10	litre	2.0892	0.0289	0.0683
	Bioethanol blend E3	litre	2.2146	0.0298	0.0690

Notes

The total CO₂-e emission factor for biofuels and biomass only includes methane and nitrous oxide emissions. This is based on ISO 14064-1:2018 and the GHG Protocol reporting requirements for combustion of biomass as direct (Scope 1) emissions. Carbon dioxide emissions from the combustion of biologically sequestered carbon are reported separately.

3.4.2 How to use the emissions factors

Note

Note that although the direct (Scope 1) carbon dioxide emissions of biomass combustion are considered carbon neutral over the short-term carbon cycle, entities should still report the carbon dioxide released through biofuel and biomass combustion⁵.

Calculate the carbon dioxide emissions in the same way as the direct emissions. Then, instead of including them within the emissions total (where CH₄ and N₂O gases are reported), list them as a separate line item called ‘biogenic emissions’. This ensures the entity is transparent regarding all potential sources of carbon dioxide from its activities.

To calculate biofuel and biomass emissions, first collect data on the quantity of fuel used then multiply this by the appropriate emission factor from the table. Applying the equation E = Q x F (section 2), this means:

E = emissions from the emissions source in kg CO₂-e per year

Q = quantity of fuel used (unit)

F = appropriate emission factors from Table 3.3

Tip

Entities can calculate emissions from biofuel blends if the specific per cent blend is known.

The equation used is:

X% biofuel blend emission factor = (X% × pure biofuel emission factor) + [(1-X%) × fossil fuel emission factor]

Example calculation

An entity uses 100 per cent biofuel in five vehicles. They use 7,000 litres of biodiesel in the reporting year:

	Emission Factor (Kg CO2e/Kg)	Calculation	Emissions (Kg CO2e)
Gas
BCO2	2.449680	7000.0 x 17147.76	17147.76
CO2	NaN	7000.0 x nan	NaN
CH4	0.018356	7000.0 x 128.49	128.49
N2O	0.035759	7000.0 x 250.31	250.31
Total_CO2e	0.054115	7000.0 x 378.81	378.81

Note: Numbers may not add due to rounding.

Fuel blend example

An entity wants to report on its Scope 1 fuel emissions (in kg CO₂-e/litre) from a specific biodiesel blend of 10 per cent. It is known that:

mineral diesel emission factor = 8888 kg CO₂-e/litre
biodiesel emission factor = 9999 kg CO₂-e/litre

Therefore, 10 per cent biodiesel blend emission factor = (10% × 8888) + [(1-10%) × 9999] = 7777 CO₂-e/litre biofuel blend

Note: Numbers may not add due to rounding.

3.4.3 How the emissions factors were derived

We applied the same methodology to the biofuels that we used to calculate the stationary combustion fuels, using the raw data in Appendix A: Derivation of fuel emission factors.

As stated in Section 3.1, four new biofuel blends were added this year: two bioethanol blends, E3 and E10. The E3 and E10 blends consist of 3 per cent and 10 per cent bioethanol respectively, with the remaining contribution made up of diesel. For the two biodiesel blends, B5 and B20, each consists of 5 per cent and 20 per cent biodiesel respectively, with the remaining contribution made up of diesel.

3.4.4 Assumptions, limitations and uncertainties

The same assumptions, limitations and uncertainties associated with transport and stationary combustion apply to biofuels. There is no difference between transport or stationary combustion of biofuels.

3.5 Transmission and distribution losses for reticulated gases

3.5.1 Emissions factors

The emission factor for reticulated natural gas transmission and distribution losses accounts for fugitive emissions from the transmission and distribution system for natural gas. These emissions occur during the delivery of the gas to the end user.

If an entity consumes reticulated gas, for example, for cooking (as shown in the example calculation under section 3.5.1), related natural gas transmission and distribution losses emissions would fall under Scope 3/Category 3. See page 41 of the GHG Protocol Corporate Value Chain (Scope 3) Accounting and Reporting Standard.

Fugitive emissions from reticulated natural gas transmission and distribution losses only fall under Scope 1 for specific sectors (eg, gas distribution businesses).

Reticulated gases are delivered via a piped gas system. Users should be aware what type of reticulated gas they are receiving: natural gas or liquefied petroleum gas (LPG). Reticulated LPG is supplied in parts of Canterbury and Otago only (natural gas is not available in the South Island). The guide assumes there are no transmission and distribution losses from reticulated LPG due to the chemical composition of the gas. Because LPG is a mixture of propane and butane, it does not emit fugitive greenhouse gases.

Table 6 details the emission factors for the transmission and distribution losses for reticulated natural gas. These represent an estimate of the average amount of carbon dioxide equivalents emitted from losses associated with the delivery (transmission and distribution) of each unit of gas consumed through local distribution networks in 2022. They are average figures and therefore make no allowance for distance from off-take point, or other factors that may vary between individual consumers.

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3.5.2 How to use the emissions factors

To calculate the emissions from transmission and distribution losses, entities should first collect data on the quantity of natural gas used and then multiply this by the emission factors for each gas. Applying the equation E = Q x F (section 2), this means:

E = emissions from the emissions source in kg CO₂-e per year

Q = quantity of fuel used (unit)

F = appropriate emission factors from table 6.

Example calculation

An entity uses 800 gigajoules of distributed natural gas in the reporting period.

CO₂ emissions = 800 × 0.0175 = 14 kg CO₂ CH₄ emissions = 800 × 1.99 = 1,592 kg CO₂-e N₂O emissions = 800 × 0.00 = 0 kg CO₂-e Total CO₂-e emissions = 800 × 2.01 = 1,606 kg CO₂-e

Note: Numbers may not add due to rounding.

3.5.3 How the emissions factors were derived

MBIE provided data on losses from transmission and distribution. The fugitive losses of natural gas are predominantly methane but include a component of carbon dioxide.

We derived the emission factor by using MBIE data for distribution and transmission gas losses, which is based on estimates provided by Firstgas.

Transmission emission estimates were modelled to include vented gas, own use gas and fugitive emissions from industry assets and work undertaken.

For distribution, an emissions estimate model using a best practice MarcoGaz template was applied, along with internationally published emission rates in the American Petroleum Institute’s Compendium of Greenhouse Gas Emissions Methodologies for the Natural Gas and Oil Industry, combined with company specific asset values. This is complemented by annual asset level leakage measurements.

The CO₂ values from these datasets are summed, and the CH₄ values are summed and then multiplied by the global warming potential of 28. These total losses are then divided by the total reticulated natural gas delivered.

3.5.4 Assumptions, limitations and uncertainties

The guide assumes there are no transmission and distribution losses from reticulated LPG.

Footnotes

ANZSIC – Australian and New Zealand Standard Industrial Classification↩︎
Climate Change (Liquid Fossil Fuels) Regulations 2008 (SR 2008/356) (as at 10 May 2024) Schedule Emissions factors for tonnes of carbon dioxide equivalent greenhouse gases per kilolitre – New Zealand Legislation.↩︎
2006 Guidelines for Greenhouse Gas Inventories, Volume 2, Energy: www.ipcc-nggip.iges.or.jp/public/2006gl/vol2.html ↩︎
2006 Guidelines for Greenhouse Gas Inventories, Volume 2, Energy: www.ipcc-nggip.iges.or.jp/public/2006gl/vol2.html ↩︎
The GHG Protocol guidance on this is accessed via: https://ghgprotocol.org/sites/default/files/Stationary_Combustion_Guidance_final_1.pdf.↩︎