1  Introduction

1.1 Purpose of this catalogue

The Ministry for the Environment supports entities taking climate action. We recognise there is strong interest, and in some cases requirements, for entities across New Zealand to measure, report and reduce their emissions. We prepared this guide to help you measure and report your entity or organisation’s greenhouse gas (GHG) emissions on a voluntary basis (see Section 1.2 for important notes on this guide’s use). Measuring and reporting empowers entities to manage and reduce emissions in line with the transition to a low-emissions, climate-resilient future.

The guide aligns with and endorses the use of the GHG Protocol Corporate Accounting and Reporting Standard (referred to here as the GHG Protocol) and ISO 14064-1:2018 (see Standards to follow). It provides information about preparing a GHG inventory Section 2, emission factors (sections 3–11) and methods to apply them to activity data. We have updated the guide in line with international best practice and New Zealand’s Greenhouse Gas Inventory 1990–2023 to provide new emission factors.

Emission factors shown in tables retain the same level of precision as provided in the emissions factor flat file and are not additionally rounded. Tables describing data used in the derivation of emission factors present values as-is. Users should take account of the uncertainties described in accompanying tables and text when applying emission factors in calculations. Example emissions calculations are rounded to three significant figures for clarity and consistency.

Most of the source data which was used in the development of these emission factors is from 2023, unless otherwise mentioned. This is done to align with New Zealand’s Greenhouse Gas Inventory 1990–2023. This contains data for the calendar years from 1990 to 2023 (inclusive). The inventory is published 15 months after the end of the period being reported on, following the United Nations Framework Convention on Climate Change (UNFCCC) reporting guidelines on annual inventories for Parties included in Annex I to the Convention. This allows time to collect and process the data and prepare its publication.

This catalogue explains how we derived the emission factors and sets out the assumptions surrounding their use. The emission factor information contained in this catalogue is not intended to be an exhaustively detailed explanation of every calculation performed, as this is not practical.

1.1.1 Feedback

We welcome your feedback on this update. Please email emissions-guide@mfe.govt.nz

1.2 Important notes

The information in the Measuring Emissions Guide does not constitute legal advice, and users should take specific advice from qualified professionals before taking any action based on information in this guide.

The information in Section 1 and Section 2 are intended as guidance only. This guidance does not replace any mandatory reporting requirements that entities may have, eg. Climate-related disclosures in line with the Aotearoa New Zealand Climate Standards (NZCS), or the Carbon Neutral Government Programme (CNGP).

Emissions factors contained within this guide may be used by entities in both voluntary and mandatory GHG inventory preparation and reporting.

The emission factors and methods in this guide are for sources common to many New Zealand organisations and support the recommended disclosure of GHG emissions consistent with the NZCS and the CNGP.

If emission factors relevant to your organisation are not included in the Measuring Emissions Guide or in Auckland Council’s spend-based emissions report (see Appendix D), we suggest using alternatives such as those published by the UK Department for Energy Security and Net Zero (formerly published by the Department for Business Energy & Industrial Strategy) and the US Environmental Protection Agency (USEPA).

This guide recognises and supports the Government’s ambition for its target of Net Zero by 2050, and the many organisations that have already set, or are looking to set, ambitious emission reduction targets aligned with a science-based approach.

Measuring your emissions enables you to set reduction targets, take climate action and report quantified progress towards your goals. For support related to reaching your organisation’s targets see the Ministry’s Interim guidance for voluntary climate change mitigation.

The information in this guide is not appropriate for use in an emissions trading scheme. Organisations required to participate in the New Zealand Emissions Trading Scheme (NZ ETS) need to comply with the scheme-specific reporting requirements. The NZ ETS regulations determine which emission factors and methods must be used to calculate and report emissions.

This guide, and the emission factors and methods, are not appropriate for a full life-cycle assessment or product carbon foot printing. The factors presented in this guide only include direct emissions from activities, and do not include all sources of emissions required for a full life-cycle assessment. If you want to do a full life-cycle assessment, we recommend using life-cycle assessment databases and/or software tools. A list of relevant life-cycle inventory databases can be found on the Life Cycle Association of New Zealand website.

Users seeking guidance on preparing a regional inventory should refer to the GHG Protocol for Community-scale Greenhouse Gas Emission Inventories.

Climate-related disclosures

New Zealand’s climate-related disclosure framework is made up of three climate standards, referred to as Aotearoa New Zealand Climate Standards (NZCS).

The aim is to support the allocation of capital towards activities that are consistent with a transition to a low-emissions, climate-resilient future. Climate-related disclosures are mandatory for around 200 entities in New Zealand, for reporting periods beginning on or after 1 January 2023. They include disclosure requirements covering governance, strategy, risk management, and metrics and targets. Metrics and targets have the requirement to disclose gross GHG emissions in metric tonnes of carbon dioxide equivalent (CO2-e) classified as:

  • Scope 1
  • Scope 2 (calculated using the location-based method)
  • Scope 3

The following information must also be disclosed in relation to the reporting entity’s GHG emissions:

  • a statement describing the standard or standards that GHG emissions have been measured in accordance with;
  • the GHG emissions consolidation approach used: equity share, financial control, or operational control;
  • the source of emission factors and the GWP values used or a reference to the GWP source;
  • a summary of specific exclusions of sources, including facilities, operations, or assets with a justification for their exclusion.

A limited number of adoption provisions apply to Scope 3 emissions.

The Aotearoa New Zealand Climate Standards and Staff Guidance for All Sectors can be found on the XRB’s website. These standards contain additional requirements, especially related to disclosures for methods, risk, reporting requirements and uncertainty management.

Carbon Neutral Government Programme

The Carbon Neutral Government Programme (CNGP) was set up by the government to accelerate the reduction of emissions within the public sector. The CNGP has published guidance for CNGP entities on measuring and reporting their GHG emissions. It includes information on what sources of GHG emissions entities need to collect, standards to follow, methods for calculating emissions, the required information to report, who to report to, and by when.

For further guidance on this consult the CNGP website or contact cngp@mfe.govt.nz.

Measuring your entity’s emissions is the first step in the journey to reducing your emissions. Developing and implementing a reduction plan is the next important step. Examples of emission reduction plans published by New Zealand corporations are available online.

Measuring emissions enables you to set reduction targets, take climate action and report quantified progress towards your goals. To reach your targets see the Ministry’s Interim guidance for voluntary climate change mitigation.

Users seeking guidance on preparing a regional inventory should refer to the GHG Protocol for Community-scale Greenhouse Gas Emission Inventories.

1.3 Gases included in the guide

Global Warming Potential (GWP) is an index to translate the level of emissions of various gases into a common measure, in order to compare the relative radiative forcing of different gases.  GWPs are calculated as the ratio of the radiative forcing that would result from the emissions of one kg of a greenhouse gas, to that from the emission of one kg of carbon dioxide over a period of time (usually 100 years). This guide uses AR5 values for GWPs.

This guide covers the following GHGs: carbon dioxide (CO2), methane (CH4), nitrous oxide (N2O), hydrofluorocarbons (HFCs), perfluorocarbons (PFCs), sulphur hexafluoride (SF6), nitrogen trifluoride (NF3) and other gases (eg, Montreal Protocol refrigerant gases or medical gases).

GWPs are applied to the non-CO2 gases to enable meaningful comparisons among the gas types compared with CO2. Where GWPs are applied to these gases, GHG emissions are commonly expressed as their carbon dioxide equivalent or CO2-e. The larger the GWP, the more a given gas warms the earth compared to CO2 over that time period. The time period usually used for GWPs is 100 years to align with UNFCCC greenhouse gas inventory reporting requirements. This is used throughout the guide.

To do this, the emissions for each non-CO2 gas is multiplied by its 100-year time-horizon GWP (GWP100) value (see Table 1.1). The IPCC provides more information on how these factors are calculated.

Throughout the guide, kilograms (kg) of CH4 and N2O are reported in kg CO2-e by multiplying the actual CH4 emissions by the GWP of 28 and actual N2O emissions by the GWP of 265, as per Table 1.1.

The GWP index value depends on two things: how effective the gas is at trapping heat while it’s in the atmosphere, and how long it stays in the atmosphere before it breaks down.  For example, methane (CH4) breaks down relatively quickly, the average CH4 molecule stays in the atmosphere for around 12 years. On the other hand, CH4 traps heat more effectively than CO2, which has a much longer lifetime.

Changes in GWP values can be due to updated scientific estimates of the energy absorption, lifetime of the gases, or to changing atmospheric concentrations of GHGs that result in a change in the energy absorption of an additional tonne of emitted gas relative to another.

The change from IPCC Fourth Assessment Report (AR4) to AR5 GWPs may cause a significant change in some entities’ inventories, including those that use large quantities of refrigerants, or that use emission factors with relatively high contributions of CH4. For those that see increases or reductions in their footprints, it would be misleading to interpret this as a true increase or reduction.

Table 1.1 shows the GWPs for N2O and CH4 comparing AR4 to AR5 values. The GWP of N2O has decreased by 11.1 per cent and the GWP of CH4 has increased by 12 per cent. AR5 GWPs for other gases such as refrigerants are shown in Table 4.2.

Table 1.1: Common GWPs
Greenhouse gases Chemical formula GWP_AR4 GWP_AR5
Carbon dioxide CO₂ 1 1
Methane CH₄ 25 28
Nitrous oxide N₂O 298 265

1.3.1 Kyoto and Montreal protocols and Paris Agreement

The Kyoto Protocol1, adopted in 1997, operationalised the UNFCCC by committing developed country parties to limit and reduce GHG emissions in accordance with agreed individual targets. It includes the following gases: CO2, CH4, N2O, HFCs, PFCs, SF6 and nitrogen trifluoride (NF3).

The Montreal Protocol2, adopted in 1987, is an international environmental agreement to protect the ozone layer by phasing out production and consumption of ozone-depleting substances (ODS). The Montreal Protocol includes chlorofluorocarbons (CFCs), hydrochlorofluorocarbons (HCFCs), hydrobromofluorocarbons (HBFCs), methyl bromide, carbon tetrachloride, methyl chloroform and halons. New Zealand prohibits imports of CFCs and HCFCs as part of our implementation of the protocol.

Many of the ozone depleting substances controlled by the Montreal Protocol are also powerful greenhouse gases. This, together with the 2016 Kigali Amendment of the Montreal Protocol to include the phase-down of HFCs, means it has a significant role in mitigating climate change.

The Paris Agreement, adopted in 2015, commits Parties to the agreement to put forward their best efforts to limit global temperature rise through nationally determined contributions (NDCs), and to strengthen these efforts over time. From 2024 onwards, New Zealand’s Greenhouse Gas Inventory reports under the Paris Agreement will apply the 100-year time horizon GWPs from the IPCC’s AR5.

1.4 Uncertainties

ISO 14064-1:2018 and the GHG Protocol require consideration of uncertainty: in particular, assessing and disclosing uncertainty associated with a GHG inventory.

  • Compared with financial accounting, carbon accounting operates in a more unpredictable, dynamic and complex environment, where uncertainty is a known and accepted concept.
  • Uncertainties associated with GHG inventories can be broadly categorised as scientific uncertainty and estimation uncertainty.
  • Scientific uncertainty arises when the science of the actual emission and/or removal process is not completely understood. Quantifying such scientific uncertainty is extremely challenging and is likely beyond the capability of most entity inventory programmes.
  • Estimation uncertainty arises any time GHG emissions are quantified and can be classed as either model uncertainty or parameter uncertainty. Model uncertainty refers to the uncertainty associated with the mathematical equations and models used to characterise the relationship between activity data and emissions. Parameter uncertainty refers to the uncertainty associated with the assumptions used and the activity data. Entities that choose to investigate uncertainty in their emission inventories will focus on the latter.

The following approach is used to disclose uncertainty, in order of preference.

  • Disclose the quantified uncertainty of the data, if known.
  • Disclose the qualitative uncertainty if known based on expert judgement from those providing the data.
  • Disclose the uncertainty ranges in the IPCC Guidelines if provided.
  • Disclose that the uncertainty is unknown.

1.5 Standards to follow

We recommend following ISO 14064-1:2018 or the GHG Protocol and this guide is written to align with both. Depending on your intended final use and users, we recommend downloading the relevant standards and using them in tandem with this guidance:

These standards provide comprehensive guidance on the core issues of GHG monitoring and reporting at an organisational level, including:

  • principles underlying monitoring and reporting
  • setting entity / organisational boundaries
  • setting reporting boundaries
  • establishing a base year
  • managing the quality of a GHG inventory
  • content of a GHG report.

1.6 How emission sources are categorised

The GHG Protocol Corporate Accounting and Reporting Standard places emission sources into Scope 1, Scope 2 and Scope 3 activities.

  • Scope 1: Direct GHG emissions from sources owned or controlled by the entity (ie, within the organisational boundary). For example, emissions from combustion of fuel in vehicles owned or controlled by the entity.
  • Scope 2: Indirect GHG emissions from the generation of purchased energy (in the form of electricity, heat or steam) that the entity uses.
  • Scope 3: Other indirect GHG emissions occurring because of the activities of the entity but generated from sources that it does not own or control (eg, air travel).

The GHG Protocol Corporate Value Chain (Scope 3) Accounting and Reporting Standard goes into more detail, providing a method to enable GHG management of the entities’ value chain emissions. In this standard, Scope 3 is broken down into 15 ‘categories’ that cover the upstream and downstream emissions associated with the entity’s activities. Some of the categories include purchased goods and services, upstream transportation and distribution, business travel and the use of sold products.

The GHG Protocol Technical Guidance for Calculating Scope 3 Emissions provides detailed guidance for each of its 15 Scope 3 categories, along with a useful table that summarises the different calculation methods available for each of these categories.

ISO 14064-1:2018 also categorises emissions as direct or indirect sources, and breaks Scope 3 down into six categories.

  • Category 1: Direct GHG emissions and removals covers the same kind of activities reported under the GHG Protocol Scope 1.

  • Category 2: Indirect GHG emissions from imported energy is the same as the GHG Protocol Scope 2.

The main difference with this standard is that Scope 3 emissions are separated into the following categories.

  • Category 3: Indirect GHG emissions from transportation, where emissions from transportation sources outside the organisation boundary are reported, such as business travel in a car that is not owned by the reporting entity.

  • Category 4: Indirect GHG emissions from products used by an entity, which covers emissions associated with goods used by the reporting entity, such as office paper.

  • Category 5: Indirect GHG emissions associated with the use of products from the organisation, which covers emissions associated with goods sold by the reporting entity, such as the lifetime usage of a car where the reporting entity is a car manufacturer.

  • Category 6: Indirect GHG emissions from other sources, which is for any emissions source (or removal) that cannot be reported in any other category.

Compared with the traditional Scope 1, Scope 2 and Scope 3 approach used in the GHG Protocol Corporate Accounting and Reporting Standard, the categories provided in the GHG Protocol Corporate Value Chain (Scope 3) Accounting and Reporting Standard and ISO 14064:2018 enable a more granular approach to GHG reporting.

The category names help better describe the activities associated with emissions sources. They enhance the quality and clarity of reporting by enabling the inclusion and expansion of indirect emissions throughout the value chain. They help identify environmental hotspots inside and outside the entity’s boundaries, which helps inform the identification of carbon reduction opportunities. Using categories also helps to manage double counting of emissions (such as between an electricity generator’s direct emissions associated with generation and the indirect emissions linked to the user of that electricity).

A similar approach of breaking down Scope 3 emissions into categories is also used by ISO 14064:2018.

This guide reports emission factors for direct (Scope 1) and indirect (Scope 2) emissions, and a limited set of indirect (Scope 3) emissions. Table 2 shows the relationship between the GHG Protocol Scopes and the ISO categories.

Table 1.2: Emissions by scope, category and source
ISO inventory category Scopes in the GHG Protocol ISO sub-category (annex B) GHG Protocol
Category 1: Direct GHG emissions and removals 1 Stationary combustion Scope 1
1 Mobile combustion Scope 1
1 Chemical and industrial processes Scope 1
1 Fugitive emissions Scope 1
1 Land use, land use change and forestry (LULUCF) Scope 1
Category 2: Indirect GHG emissions from imported energy 2 Purchased (imported) electricity and steam Scope 2
2 Energy Scope 2
Category 3: Indirect GHG emissions from transportation 3 Upstream emissions from fuel generation 3. Fuel- and energy-related activities
3 Upstream transport and distribution of goods purchased 4. Upstream transportation and distribution
3 Downstream transport and distribution of goods sold 9. Downstream transportation and distribution
3 Employee commuting 7. Employee commuting
3 Business travel in vehicles not owned or operated by the organisation 6. Business travel
3 Client and visitor transport 6. Business travel
3 Business hotel stay 6. Business travel
Category 4: Indirect GHG emissions from products used by the organisation 3 Purchased goods and services, including upstream emissions 1. Purchased goods and services
3 Capital goods, including upstream emissions 2. Capital goods
3 Transmission of energy (transmission and distribution losses)
3 Waste disposal and treatment (liquid and solid) 5. Waste generated in operations
3 Equipment leased by reporting organisation 8. Upstream leased assets
Category 5: Indirect GHG emissions associated with use of products from the organisation 3 Processing of sold goods, or intermediate products sold by the organisation to another 10. Processing of sold products
3 Use stage of product sold 11. Use of sold product
3 Downstream leased assets owned by the organisation and leased to others 13. Downstream leased assets 14. Franchises
3 End-of-life stage of product sold 12. End-of-life treatment of sold products
3 Investments such as equity debt, investment debt, project finance and others 15. Investments
Category 6: Indirect GHG emissions from other sources 3

Note1: Depending on your entity’s reporting and financial boundaries, some emission sources may be either Scope 1 or Scope 3.

Note2: Spend-based emission factors might be used for some of the indirect emissions where better quality, activity specific emission factors may be lacking.

Note3: Emissions inventories, in line with the Greenhouse Gas Protocol, report only Kyoto Protocol gases under direct(Scope 1) emissions. All non-Kyoto gases, such as the Montreal Protocol refrigerant gases or medical gases, should be reported separately as ‘other gases’.

Both the ISO 14064-1:2018 and GHG Corporate Protocol require that entities calculate the emissions of each GHG separately and quantify them as CO2-e. Example calculations in this guide show this format (see also the 2024 example report for greenhouse gas emissions). While the NZCS does not mandate a single approach for measuring GHG emissions, the International Sustainability Standards Board requires entities to report in accordance with the GHG Protocol, unless there are other requirements, for instance, from an exchange they are listed on.

  1. https://unfccc.int/kyoto_protocol↩︎

  2. https://www.unep.org/ozonaction/who-we-are/about-montreal-protocol↩︎

  3. Published by the International Organization for Standardization. This standard is closely based on the GHG Protocol.↩︎

  4. Developed jointly by the World Resources Institute (WRI) and the World Business Council for Sustainable Development (WBCSD).↩︎