| Emissions Source | Unit | kg CO₂–e/unit | CO₂/unit (kg CO₂–e) | CH₄/unit (kg CO₂–e) | N₂O/unit (kg CO₂–e) | Uncertainties |
|---|---|---|---|---|---|---|
| Commercial Use | ||||||
| Natural Gas (GJ) | GJ | 54.2862 | 54.1363 | 0.126 | 0.02385 | CO2e ±2.0%, CO2 ±2.0%, CH4 ±50.0%, N2O ±50.0% |
| Natural Gas (kWh) | kWh | 0.19543 | 0.194891 | 0.0004536 | 0.00008586 | CO2e ±2.0%, CO2 ±2.0%, CH4 ±50.0%, N2O ±50.0% |
| Coal – Bituminous | kg | 2.65641 | 2.63736 | 0.00787095 | 0.0111739 | CO2e ±2.0%, CO2 ±2.0%, CH4 ±50.0%, N2O ±50.0% |
| Coal – Sub–Bituminous | kg | 2.00494 | 1.99101 | 0.00575724 | 0.00817322 | CO2e ±2.0%, CO2 ±2.0%, CH4 ±50.0%, N2O ±50.0% |
| Coal – Lignite | kg | 1.43027 | 1.42045 | 0.00405799 | 0.00576089 | CO2e ±2.0%, CO2 ±2.0%, CH4 ±50.0%, N2O ±50.0% |
| Coal – Default | kg | 2.08783 | 2.07318 | 0.00605494 | 0.00859585 | CO2e ±2.0%, CO2 ±2.0%, CH4 ±50.0%, N2O ±50.0% |
| LPG | kg | 2.97164 | 2.96373 | 0.00665 | 0.00125875 | CO2e ±2.0%, CO2 ±2.0%, CH4 ±50.0%, N2O ±50.0% |
| Diesel | litre | 2.6759 | 2.65984 | 0.0102389 | 0.00581423 | CO2e ±1.02%, CO2 ±1.0%, CH4 ±50.0%, N2O ±50.0% |
| Heavy Fuel Oil | litre | 3.05359 | 3.0366 | 0.0108367 | 0.00615367 | CO2e ±1.02%, CO2 ±1.0%, CH4 ±50.0%, N2O ±50.0% |
| Light Fuel Oil | litre | 2.97088 | 2.95401 | 0.0107608 | 0.00611058 | CO2e ±1.02%, CO2 ±1.0%, CH4 ±50.0%, N2O ±50.0% |
| Industrial Use | ||||||
| Natural Gas (GJ) | GJ | 54.1854 | 54.1363 | 0.0252 | 0.02385 | CO2e ±2.0%, CO2 ±2.0%, CH4 ±50.0%, N2O ±50.0% |
| Natural Gas (kWh) | kWh | 0.195067 | 0.194891 | 0.00009072 | 0.00008586 | CO2e ±2.0%, CO2 ±2.0%, CH4 ±50.0%, N2O ±50.0% |
| Coal – Bituminous | kg | 2.65641 | 2.63736 | 0.00787095 | 0.0111739 | CO2e ±2.0%, CO2 ±2.0%, CH4 ±50.0%, N2O ±50.0% |
| Coal – Sub–Bituminous | kg | 2.00494 | 1.99101 | 0.00575724 | 0.00817322 | CO2e ±2.0%, CO2 ±2.0%, CH4 ±50.0%, N2O ±50.0% |
| Coal – Lignite | kg | 1.43027 | 1.42045 | 0.00405799 | 0.00576089 | CO2e ±2.0%, CO2 ±2.0%, CH4 ±50.0%, N2O ±50.0% |
| Coal – Default | kg | 1.96451 | 1.95079 | 0.00567207 | 0.00805232 | CO2e ±2.0%, CO2 ±2.0%, CH4 ±50.0%, N2O ±50.0% |
| LPG | kg | 2.96632 | 2.96373 | 0.00133 | 0.00125875 | CO2e ±2.0%, CO2 ±2.0%, CH4 ±50.0%, N2O ±50.0% |
| Diesel | litre | 2.66873 | 2.65984 | 0.00307167 | 0.00581423 | CO2e ±1.0%, CO2 ±1.0%, CH4 ±50.0%, N2O ±50.0% |
| Heavy Fuel Oil | litre | 3.04601 | 3.0366 | 0.003251 | 0.00615367 | CO2e ±1.0%, CO2 ±1.0%, CH4 ±50.0%, N2O ±50.0% |
| Light Fuel Oil | litre | 2.96335 | 2.95401 | 0.00322823 | 0.00611058 | CO2e ±1.0%, CO2 ±1.0%, CH4 ±50.0%, N2O ±50.0% |
| Residential Use | ||||||
| Coal – Bituminous | kg | 2.88466 | 2.63736 | 0.236129 | 0.0111739 | CO2e ±4.49%, CO2 ±2.0%, CH4 ±50.0%, N2O ±50.0% |
| Coal – Sub–Bituminous | kg | 2.1719 | 1.99101 | 0.172717 | 0.00817322 | CO2e ±4.38%, CO2 ±2.0%, CH4 ±50.0%, N2O ±50.0% |
| Coal – Lignite | kg | 1.54795 | 1.42045 | 0.12174 | 0.00576089 | CO2e ±4.34%, CO2 ±2.0%, CH4 ±50.0%, N2O ±50.0% |
| Coal – Default | kg | 2.15778 | 1.97777 | 0.171883 | 0.00813375 | CO2e ±4.39%, CO2 ±2.0%, CH4 ±50.0%, N2O ±50.0% |
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 Corporate Standard we provide emission factors for direct (Scope 1) sources by gas, which allows separate estimation of carbon dioxide, methane and nitrous oxide emissions calculations.
The fuel emission factors are based on data from New Zealand’s Greenhouse Gas Inventory 1990–2024.
3.1 Overview of emission factor changes from 2025 to 2026
| Section | Total EFs | EFs added | EFs removed | EFs changed | Explanation for change |
|---|---|---|---|---|---|
| Biofuel and Biomass | 13 | 0 | 0 | 4 | MBIE fuel source data was refreshed. |
| Stationary Combustion of Fuels | 24 | 0 | 0 | 9 | MBIE fuel properties, coal demand, gas factors and liquid fuel factors were refreshed. |
| Transmission and distribution losses | 2 | 0 | 0 | 2 | Gas transmission/distribution loss and delivered-gas inputs changed. |
| Transport Fuel | 10 | 0 | 0 | 5 | MBIE fuel-property and transport fuel-factor source inputs were refreshed. |
For detailed information on the emission factor changes, download the Emission factor changes CSV file from Appendix G.
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 1.6.
3.2.1 Emission factors
Table 3.2 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 1990–2024.
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.
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 GHG inventory development
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 x F this means:
- E = emissions from the emissions source in kg CO2-e within the reporting period
- Q = quantity of fuel used (unit)
- F = appropriate emission factors from Table 3.2.
Entities typically report emissions using data on the amount of fuel used during the reporting period.
3.2.2.1 STATIONARY COMBUSTION: EXAMPLE CALCULATION
An entity uses 1,400 kg of LPG to heat an office building in the reporting year:
| Gas | Calculation | Emissions (kg CO₂-e) |
|---|---|---|
| CO₂ emissions | 1,400 x 2.96373 kg CO₂-e per kg | 4,150 kg CO₂-e |
| CH₄ emissions | 1,400 x 0.00665 kg CO₂-e per kg | 9.31 kg CO₂-e |
| N₂O emissions | 1,400 x 0.00125875 kg CO₂-e per kg | 1.76 kg CO₂-e |
| Total CO₂-e emissions | 1,400 x 2.97164 kg CO₂-e per kg | 4,160 kg CO₂-e |
Note: Numbers may not add due to rounding.
3.2.3 Emission factor derivation methodology
We derived the kg CO2-e per activity unit emission factors supplied in Table 3.2 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 1990–2024 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 values are then multiplied by their AR5 global warming potentials, 28 and 265 respectively.
The calorific values are in Appendix A 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 3.2 using calorific values, listed in Appendix A: Derivation of fuel emission factors.
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 Emission factors
Transport fuels are used in an engine to move a vehicle. Table 3.3 lists the emission factors.
| Emissions Source | Unit | kg CO₂–e/unit | CO₂/unit (kg CO₂–e) | CH₄/unit (kg CO₂–e) | N₂O/unit (kg CO₂–e) | Uncertainties |
|---|---|---|---|---|---|---|
| Transport Fuel | ||||||
| Aviation fuel – Kerosene (GJ) | GJ | 68.4549 | 67.9381 | 0.0133 | 0.5035 | CO2e ±1.06%, CO2 ±1.0%, CH4 ±50.0%, N2O ±50.0% |
| Aviation gas (GJ) | GJ | 66.4083 | 65.8915 | 0.0133 | 0.5035 | CO2e ±1.06%, CO2 ±1.0%, CH4 ±50.0%, N2O ±50.0% |
| Regular Petrol | litre | 2.36143 | 2.2619 | 0.0302118 | 0.0693172 | CO2e ±1.87%, CO2 ±1.0%, CH4 ±50.0%, N2O ±50.0% |
| Premium Petrol | litre | 2.41525 | 2.31425 | 0.0306602 | 0.0703459 | CO2e ±1.86%, CO2 ±1.0%, CH4 ±50.0%, N2O ±50.0% |
| Diesel | litre | 2.67177 | 2.63045 | 0.00394905 | 0.0373749 | CO2e ±1.21%, CO2 ±1.0%, CH4 ±50.0%, N2O ±50.0% |
| LPG | litre | 1.61825 | 1.57315 | 0.0437698 | 0.00133629 | CO2e ±2.37%, CO2 ±2.0%, CH4 ±50.0%, N2O ±50.0% |
| Heavy Fuel Oil | litre | 3.0647 | 3.0366 | 0.00758566 | 0.0205122 | CO2e ±1.05%, CO2 ±1.0%, CH4 ±50.0%, N2O ±50.0% |
| Light Fuel Oil | litre | 2.98191 | 2.95401 | 0.00753254 | 0.0203686 | CO2e ±1.06%, CO2 ±1.0%, CH4 ±50.0%, N2O ±50.0% |
| Aviation fuel – Kerosene (litre) | litre | 2.51938 | 2.50036 | 0.000489487 | 0.0185306 | CO2e ±1.06%, CO2 ±1.0%, CH4 ±50.0%, N2O ±50.0% |
| Aviation gas (litre) | litre | 2.24904 | 2.23153 | 0.000450428 | 0.0170519 | CO2e ±1.06%, CO2 ±1.0%, CH4 ±50.0%, N2O ±50.0% |
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 GHG inventory development
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 this means:
- E = emissions from the emissions source in kg CO2-e within the reporting period
- Q = quantity of fuel used (unit)
- F = appropriate emission factors from Table 3.3
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 3.3.3.
3.3.2.1 TRANSPORT FUEL: EXAMPLE CALCULATION
Example calculation of 40000 liters of Regular Petrol used.
| Gas | Calculation | Emissions (kg CO₂-e) |
|---|---|---|
| CO₂ emissions | 40,000 x 2.2619 kg CO₂-e per litre | 90,500 kg CO₂-e |
| CH₄ emissions | 40,000 x 0.0302118 kg CO₂-e per litre | 1,210 kg CO₂-e |
| N₂O emissions | 40,000 x 0.0693172 kg CO₂-e per litre | 2,770 kg CO₂-e |
| Total CO₂-e emissions | 40,000 x 2.36143 kg CO₂-e per litre | 94,500 kg CO₂-e |
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. 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. See Section 7.2.
3.3.4 Emission factor derivation methodology
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.
3.3.5 Assumptions, limitations and uncertainties
We derived the kg CO2-e per activity unit emission factors in Table 3.3 using calorific values. All emission factors incorporate relevant oxidation factors sourced from the 2006 IPCC Guidelines for National Greenhouse Gas Inventories3.
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
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 3.4 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 3.4 details the emission conversion factors for the GHG emissions from the combustion of biofuels.
| Emissions Source | Unit | kg CO₂–e/unit | CO₂/unit (kg CO₂–e) | CH₄/unit (kg CO₂–e) | N₂O/unit (kg CO₂–e) | Uncertainties | BCO₂/unit (kg CO₂–e) |
|---|---|---|---|---|---|---|---|
| Biofuel | |||||||
| Bioethanol (GJ) | GJ | 2.518 | 0 | 0.504 | 2.014 | CO2e ±41.23%, CO2 ±1.0%, CH4 ±50.0%, N2O ±50.0% | 64.2 |
| Biodiesel (GJ) | GJ | 1.48582 | 0 | 0.504 | 0.981825 | CO2e ±37.14%, CO2 ±1.0%, CH4 ±50.0%, N2O ±50.0% | 67.26 |
| Bioethanol (litre) | litre | 0.0594248 | 0 | 0.0118944 | 0.0475304 | CO2e ±41.23%, CO2 ±1.0%, CH4 ±50.0%, N2O ±50.0% | 1.51512 |
| Biodiesel (litre) | litre | 0.0541153 | 0 | 0.0183562 | 0.0357591 | CO2e ±37.14%, CO2 ±1.0%, CH4 ±50.0%, N2O ±50.0% | 2.44968 |
| Bioethanol blend E3 | litre | 2.29237 | 2.19404 | 0.0296623 | 0.0686636 | CO2e ±1.89%, CO2 ±1.0%, CH4 ±50.0%, N2O ±50.0% | 0.0454536 |
| Bioethanol blend E10 | litre | 2.17967 | 2.08282 | 0.0287836 | 0.0680643 | CO2e ±1.95%, CO2 ±1.0%, CH4 ±50.0%, N2O ±50.0% | 0.151512 |
| Biodiesel blend B5 | litre | 2.54089 | 2.49893 | 0.0046694 | 0.0372941 | CO2e ±1.23%, CO2 ±1.0%, CH4 ±50.0%, N2O ±50.0% | 0.122484 |
| Biodiesel blend B20 | litre | 2.14824 | 2.10436 | 0.00683048 | 0.0370517 | CO2e ±1.31%, CO2 ±1.0%, CH4 ±50.0%, N2O ±50.0% | 0.489936 |
| Biomass – Commercial Use | |||||||
| Wood – Chips | kg | 0.114655 | 0 | 0.101808 | 0.0128472 | CO2e ±44.75%, CH4 ±50.0%, N2O ±50.0% | 1.35542 |
| Wood – Pellets | kg | 0.143701 | 0 | 0.127599 | 0.0161018 | CO2e ±44.75%, CH4 ±50.0%, N2O ±50.0% | 1.69879 |
| Biomass – Manufacturing Use | |||||||
| Wood – Chips | kg | 0.023028 | 0 | 0.0101808 | 0.0128472 | CO2e ±35.59%, CH4 ±50.0%, N2O ±50.0% | 1.35542 |
| Wood – Pellets | kg | 0.0288618 | 0 | 0.0127599 | 0.0161018 | CO2e ±35.59%, CH4 ±50.0%, N2O ±50.0% | 1.69879 |
| Wood – Green | kg | 0.0135098 | 0 | 0.00597274 | 0.00753702 | CO2e ±35.59%, CH4 ±50.0%, N2O ±50.0% | 0.79518 |
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.
3.4.1 GHG inventory development
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 this means:
- E = emissions from the emissions source in kg CO2-e within the reporting period
- Q = quantity of fuel used (unit)
- F = appropriate emission factors from Table 3.4
Entities can calculate emissions from biofuel blends if the specific per cent blend is known.
\[ \begin{aligned} \text{X\% biofuel blend emission factor} &= \\ \big( X\% \times \text{pure biofuel emission factor} \big) &+ \\ \Big( (1 - X\%) \times \text{fossil fuel emission factor} \Big) \end{aligned} \]
3.4.1.1 BIOFUELS AND BIOMASS: EXAMPLE CALCULATION
An entity uses 100 per cent biofuel in five vehicles. They use 7,000 litres of biodiesel in the reporting year:
Non-biogenic component (reported as Scope/Category 1)
| Gas | Calculation | Emissions (kg CO₂-e) |
|---|---|---|
| CO₂ emissions | 7,000 x 0 kg CO₂-e per litre | 0 kg CO₂-e |
| CH₄ emissions | 7,000 x 0.0183562 kg CO₂-e per litre | 128 kg CO₂-e |
| N₂O emissions | 7,000 x 0.0357591 kg CO₂-e per litre | 250 kg CO₂-e |
| Total CO₂-e emissions | 7,000 x 0.0541153 kg CO₂-e per litre | 379 kg CO₂-e |
Biogenic component (reported separately)
| Gas | Calculation | Emissions (kg CO₂-e) |
|---|---|---|
| BCO₂ emissions | 7,000 x 2.44968 kg CO₂-e per litre | 17,100 kg CO₂-e |
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 2.67177 kg CO2-e/litre
- biodiesel emission factor 0.0541153 kg CO2-e/litre
Therefore, 10 per cent biodiesel blend emission factor = (10% × 0.0541153) + [(1-10%) × 2.67177] = 2.41000453 kg CO2-e/litre biofuel blend
Note: Numbers may not add due to rounding.
3.4.2 Emission factor derivation methodology
We applied the same methodology to the biofuels that we used to calculate the stationary combustion fuels, using the raw data in Appendix A.
The E3 and E10 bioethanol 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.
3.4.3 Assumptions, limitations and uncertainties
The same assumptions, limitations and uncertainties associated with transport and stationary combustion apply to biofuels.
3.5 Transmission and distribution losses for reticulated gases
3.5.1 Emission 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 3.5.2.1), 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 3.5 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 2024. They are average figures and therefore make no allowance for distance from off-take point, or other factors that may vary between individual consumers.
| Emissions Source | Unit | kg CO₂–e/unit | CO₂/unit (kg CO₂–e) | CH₄/unit (kg CO₂–e) |
|---|---|---|---|---|
| Reticulated Gases | ||||
| Natural gas used (GJ) | GJ | 1.61768 | 0.0140783 | 1.6036 |
| Natural gas used (kWh) | kWh | 0.00582364 | 0.0000506819 | 0.00577296 |
3.5.2 GHG inventory development
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 this means:
- E = emissions from the emissions source in kg CO2-e within the reporting period
- Q = quantity of fuel used (unit)
- F = appropriate emission factors from Table 3.5.
3.5.2.1 TRANSMISSION AND DISTRIBUTION LOSSES: EXAMPLE CALCULATION
An entity uses 800 gigajoules of distributed natural gas in the reporting period.
| Gas | Calculation | Emissions (kg CO₂-e) |
|---|---|---|
| CO₂ emissions | 800 x 0.0140783 kg CO₂-e per GJ | 11.3 kg CO₂-e |
| CH₄ emissions | 800 x 1.6036 kg CO₂-e per GJ | 1,280 kg CO₂-e |
| Total CO₂-e emissions | 800 x 1.61768 kg CO₂-e per GJ | 1,290 kg CO₂-e |
Note: Numbers may not add due to rounding.
3.5.3 Emission factor derivation methodology
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.
ANZSIC – Australian and New Zealand Standard Industrial Classification↩︎
Climate Change (Liquid Fossil Fuels) Regulations 2008 (SR 2008/356) (as at 10 May 2024) Schedule Emission 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.↩︎