National foreword

This British Standard is the UK implementation of ISO 50100:2026.

The UK participation in its preparation was entrusted to Technical Committee SEM/1, Energy Management.

A list of organizations represented on this committee can be obtained on request to its committee manager.

Many organizations want to achieve and demonstrate net zero and/or carbon neutrality through decarbonization of their activities. Requirements for achieving and demonstrating net zero are specified in BS ISO 14060 (expected to publish in early 2027); requirements for achieving and demonstrating carbon neutrality are specified in BS ISO 14068:2026.

It is the opinion of the UK committee that the approach to decarbonization in this standard does not fully align with the requirements in BS ISO 14060 and BS ISO 14068:2026 given that, in addition to direct and indirect greenhouse gas (GHG) emissions from energy (also known as Scope 1 and Scope 2 emissions; see Subclause 3.5.4 and Subclause 3.5.5), it only includes indirect GHG emissions associated with the generation or transmission of energy (Scope 3 category 3), and not the complete organizational GHG inventory (i.e. it excludes most Scope 3 emissions). This standard also only focuses on three of the seven GHG types (see Annex B). Organizations seeking to achieve net zero and/or carbon neutrality are advised to refer to BS ISO 14060 or BS ISO 14068:2026.

The UK committee advises organizations that wish to demonstrate compliance with the UK’s Energy Savings Opportunity Scheme (ESOS) regulation requirements (see www.gov.uk/guidance/energy-savings-opportunity-scheme-esos) to consult the following when applying this standard:

PAS 51215‑1:2025Energy and decarbonization assessment – Part 1: Process – Specification
PAS 51215‑2:2025Energy and decarbonization assessment – Part 2: Competencies of lead assessors and assessment teams – Specification

The UK committee notes that this standard includes processes and requirements covering Scope 3 emissions that are fuel- and energy-related activities, whereas PAS 51215‑1:2025 and PAS 51215‑2:2025 cover Scope 3 emissions from business travel (Scope 3 category 6) and any additional Scope 3 emissions an organization wishes to include.

Further information on the categorization of Scope 3 emissions is available in the Greenhouse Gas Protocol’s Technical Guidance for Calculating Scope 3 Emissions.

Contractual and legal considerations

This publication has been prepared in good faith, however no representation, warranty, assurance or undertaking (express or implied) is or will be made, and no responsibility or liability is or will be accepted by BSI in relation to the adequacy, accuracy, completeness or reasonableness of this publication. All and any such responsibility and liability is expressly disclaimed to the full extent permitted by the law.

This publication is provided as is, and is to be used at the recipient’s own risk.

The recipient is advised to consider seeking professional guidance with respect to its use of this publication.

This publication is not intended to constitute a contract. Users are responsible for its correct application.

Compliance with a British Standard cannot confer immunity from legal obligations.

This British Standard was published under the authority of the Standards Policy and Strategy Committee on 31 October 2026.

Foreword

ISO (the International Organization for Standardization) is a worldwide federation of national standards bodies (ISO member bodies). The work of preparing International Standards is normally carried out through ISO technical committees. Each member body interested in a subject for which a technical committee has been established has the right to be represented on that committee. International organizations, governmental and non-governmental, in liaison with ISO, also take part in the work. ISO collaborates closely with the International Electrotechnical Commission (IEC) on all matters of electrotechnical standardization.

The procedures used to develop this document and those intended for its further maintenance are described in the ISO/IEC Directives, Part 1. In particular, the different approval criteria needed for the different types of ISO document should be noted. This document was drafted in accordance with the editorial rules of the ISO/IEC Directives, Part 2 (see www.iso.org/directives).

ISO draws attention to the possibility that the implementation of this document may involve the use of (a) patent(s). ISO takes no position concerning the evidence, validity or applicability of any claimed patent rights in respect thereof. As of the date of publication of this document, ISO had not received notice of (a) patent(s) which may be required to implement this document. However, implementers are cautioned that this may not represent the latest information, which may be obtained from the patent database available at www.iso.org/patents. ISO shall not be held responsible for identifying any or all such patent rights.

Any trade name used in this document is information given for the convenience of users and does not constitute an endorsement.

For an explanation of the voluntary nature of standards, the meaning of ISO specific terms and expressions related to conformity assessment, as well as information about ISO’s adherence to the World Trade Organization (WTO) principles in the Technical Barriers to Trade (TBT), see www.iso.org/iso/foreword.html.

This document was prepared by Technical Committee ISO/TC 301, Energy management and energy savings.

Any feedback or questions on this document should be directed to the user’s national standards body. A complete listing of these bodies can be found at www.iso.org/members.html.

Introduction

0.1 Importance of decarbonization

Nearly 75 % of global anthropogenic greenhouse gas (GHG) emissions are from the generation and consumption of energy.^[1^] This document is designed to help organizations of all types and sizes to reduce their energy-related GHG emissions (noted as ERGE in this document) in line with the organization’s related targets. Figure 1 illustrates the relationship between greenhouse gas and ERGE.

This document outlines the requirements and provides guidance for organizations to develop a pathway that transitions their energy consumption to meet their ERGE targets.

0.2 Achieving decarbonization

To achieve decarbonization, as established by the Paris Agreement^[2^] and Nationally Determined Contributions (NDCs)^[3^], organizations across all sectors must take action and implement actions to reduce the energy consumption of their energy uses and switch to the consumption of low or zero-carbon emission energy types (e.g. energy with a lower GHG emission factor).

This document provides organizations with a comprehensive decarbonization process for ERGE that can be integrated into the organization’s operations. This process is based on a decarbonization plan leading to specific ERGE reduction actions producing demonstrable results.

Processes to manage energy have been shown to effectively reduce energy consumption^[4^]. ISO 50001:2018^[5^] is an example of an energy management system (EnMS) that can serve as the foundation for reducing GHG emissions from energy consumption. While this document is not a management system standard, the processes it outlines can be effectively integrated with an EnMS or any other management system that includes requirements to quantifiably improve energy performance. Annex A shows the relationship between this document and ISO 50001:2018, which complement each other to enable an organization to achieve a performance-based decarbonization strategy.

This document is designed to work with the existing GHG quantification documents (e.g. ISO 14064‑1,^[6^] GHG Protocol,^[7^] etc.).

This document enables an organization to make claims regarding:

its plan to meet ERGE targets (validation);
its achievement of ERGE targets based on historical data (verification);
both its plan and achievement of ERGE targets.

NOTE ISO 14068‑1:2023^[8^] sets out the requirements for claims around the achievement of carbon neutrality, and ISO 14060^[9^] for being on a pathway to net zero.

0.3 Benefits

This document provides a systematic approach to developing a pathway for transitioning an organization’s energy consumption to reduce ERGE in order to help organizations:

align internal systems, processes and input from interested parties to more effectively reduce ERGE;
improve the availability and quality of data and information shared internally and with interested parties;
create a culture for reducing ERGE, involving leveraging synergies across different means such as EnMS, energy efficiency, renewable energy and technology improvements;
provide internal and external interested parties assurance that the organization has established one or more clear and transparent Scope 1 ERGE and Scope 2 ERGE targets;
develop ERGE reduction action plans implemented over time, resulting in achievement of the organizational decarbonization strategy;
demonstrate achievement of past ERGE targets and the ability to achieve future ERGE targets.

0.4 Compatibility

This document contains requirements and can be used to assess conformity for repeatable and reproducible results related to ERGE.

1 Scope

This document specifies requirements and provides guidance that enable an organization to reduce its energy-related greenhouse gas (GHG) emissions (ERGE).

This document is applicable:

to any organization regardless of its type, size, complexity, geographical location, organizational culture or the products and services it provides;
to energy-related Scope 1 emissions and Scope 2 emissions;
irrespective of the quantity, use or types of energy consumed.

This document requires demonstration of absolute ERGE reduction aligned with ERGE target(s).

Annex A provides information on the relationship between ISO 50001:2018 and this document.

Annex B provides information on GHG emissions and GHG emission factors.

Annex C provides guidance related to the decarbonization planning.

2 Normative references

3 Terms and definitions

3.1 Terms related to organization

3.2 Terms related to requirement

3.3 Terms related to performance

3.4 Terms related to energy

3.5 Terms related to global warming and climate change

3.6 Abbreviated terms

3.7 Symbols

4 Commitment of the organization

4.1 Requirements related to the decarbonization boundary

4.2 Commitment by top management

4.3 Communications

4.4 Risks and opportunities associated with decarbonization

4.5 ERGE inclusions and exclusions review

5 Decarbonization plan

6 ERGE quantification

6.1 General

6.2 Calculation approach using energy consumption and GHG emission factors

6.3 Direct measurement

6.4 Quantification method contents

7 Base year ERGE

7.1 General

7.2 Quantification of base year ERGE

8 ERGE targets

8.1 Setting ERGE targets

8.2 Estimated future ERGE and ERGE reduction needed

9 ERGE reduction activities

9.1 General

9.2 Development of ERGE reduction action plans

9.3 Updating the ERGE reduction action plans

9.4 Design and procurement

10 Monitoring ERGE

10.1

10.2

11 Decarbonization report

11.1 General

11.2 Decarbonization report content

12 Decarbonization claim

Bibliography