ISO/FDIS 19870-1
(Main)Hydrogen technologies — Methodology for determining the greenhouse gas emissions associated with the hydrogen supply chain — Part 1: Emissions associated with the production of hydrogen up to the production gate
Hydrogen technologies — Methodology for determining the greenhouse gas emissions associated with the hydrogen supply chain — Part 1: Emissions associated with the production of hydrogen up to the production gate
ISO 14044 requires the goal and scope of an LCA to be clearly defined and be consistent with the intended application. Due to the iterative nature of LCA, it is possible that the LCA scope needs to be refined during the study. This document specifies methodologies that can be applied to determine the carbon footprint of a product (CFP) or partial CFP of a hydrogen product in line with ISO 14067. The goals and scopes of the methodologies correspond to either approach a) or b), given below, that ISO 14040:2006, A.2 gives as two possible approaches to LCA. a) An approach that assigns elementary flows and potential environmental impacts to a specific product system, typically as an account of the history of the product. b) An approach that studies the environmental consequences of possible (future) changes between alternative product systems. Approaches a) and b) have become known as attributional and consequential, respectively, with complementary information accessible in the ILCD handbook.[1] There are numerous pathways to produce hydrogen from various primary energy sources. This document describes the requirements and evaluation methods applied to several hydrogen production pathways of interest: electrolysis, steam methane reforming (with carbon capture and storage), co-production and coal gasification (with carbon capture and storage), auto-thermal reforming (with carbon capture and storage), hydrogen as a co-product in industrial applications and hydrogen from biomass waste as feedstock. This document also considers the GHG emissions due to the conditioning or conversion of hydrogen into different physical forms and chemical carriers: — hydrogen liquefaction; — production, transport and cracking of ammonia as a hydrogen carrier; — hydrogenation, transport and dehydrogenation of liquid organic hydrogen carriers (LOHCs). This document considers the GHG emissions due to hydrogen and/or hydrogen carriers’ transport up to the consumption gate. It is possible that future revisions of this document will consider additional hydrogen production, conditioning, conversion and transport methods. This document applies to and includes every delivery along the supply chain up to the final delivery to the consumption gate (see Figure 2 in the Introduction). This document also provides additional information related to evaluation principles, system boundaries and expected reported metrics in the form of Annexes A to K, that are accessible via the online ISO portal (https://standards.iso.org/iso/ts/19870/ed-1/en).
Technologies de l'hydrogène — Méthodologie pour déterminer les émissions de gaz à effet de serre associées à la chaîne d'approvisionnement en hydrogène — Partie 1: Émissions associées à la production d'hydrogène jusqu'au point de production
General Information
- Status
- Not Published
- Technical Committee
- ISO/TC 197/SC 1 - ISO/TC 197/SC 1
- Current Stage
- 5000 - FDIS registered for formal approval
- Start Date
- 31-Oct-2025
- Completion Date
- 17-Nov-2025
Relations
- Effective Date
- 15-Mar-2025
- Effective Date
- 16-Dec-2023
ISO/FDIS 19870-1 - Hydrogen technologies — Methodology for determining the greenhouse gas emissions associated with the hydrogen supply chain — Part 1: Emissions associated with the production of hydrogen up to the production gate Released:7. 01. 2026
REDLINE ISO/FDIS 19870-1 - Hydrogen technologies — Methodology for determining the greenhouse gas emissions associated with the hydrogen supply chain — Part 1: Emissions associated with the production of hydrogen up to the production gate Released:7. 01. 2026
Frequently Asked Questions
ISO/FDIS 19870-1 is a draft published by the International Organization for Standardization (ISO). Its full title is "Hydrogen technologies — Methodology for determining the greenhouse gas emissions associated with the hydrogen supply chain — Part 1: Emissions associated with the production of hydrogen up to the production gate". This standard covers: ISO 14044 requires the goal and scope of an LCA to be clearly defined and be consistent with the intended application. Due to the iterative nature of LCA, it is possible that the LCA scope needs to be refined during the study. This document specifies methodologies that can be applied to determine the carbon footprint of a product (CFP) or partial CFP of a hydrogen product in line with ISO 14067. The goals and scopes of the methodologies correspond to either approach a) or b), given below, that ISO 14040:2006, A.2 gives as two possible approaches to LCA. a) An approach that assigns elementary flows and potential environmental impacts to a specific product system, typically as an account of the history of the product. b) An approach that studies the environmental consequences of possible (future) changes between alternative product systems. Approaches a) and b) have become known as attributional and consequential, respectively, with complementary information accessible in the ILCD handbook.[1] There are numerous pathways to produce hydrogen from various primary energy sources. This document describes the requirements and evaluation methods applied to several hydrogen production pathways of interest: electrolysis, steam methane reforming (with carbon capture and storage), co-production and coal gasification (with carbon capture and storage), auto-thermal reforming (with carbon capture and storage), hydrogen as a co-product in industrial applications and hydrogen from biomass waste as feedstock. This document also considers the GHG emissions due to the conditioning or conversion of hydrogen into different physical forms and chemical carriers: — hydrogen liquefaction; — production, transport and cracking of ammonia as a hydrogen carrier; — hydrogenation, transport and dehydrogenation of liquid organic hydrogen carriers (LOHCs). This document considers the GHG emissions due to hydrogen and/or hydrogen carriers’ transport up to the consumption gate. It is possible that future revisions of this document will consider additional hydrogen production, conditioning, conversion and transport methods. This document applies to and includes every delivery along the supply chain up to the final delivery to the consumption gate (see Figure 2 in the Introduction). This document also provides additional information related to evaluation principles, system boundaries and expected reported metrics in the form of Annexes A to K, that are accessible via the online ISO portal (https://standards.iso.org/iso/ts/19870/ed-1/en).
ISO 14044 requires the goal and scope of an LCA to be clearly defined and be consistent with the intended application. Due to the iterative nature of LCA, it is possible that the LCA scope needs to be refined during the study. This document specifies methodologies that can be applied to determine the carbon footprint of a product (CFP) or partial CFP of a hydrogen product in line with ISO 14067. The goals and scopes of the methodologies correspond to either approach a) or b), given below, that ISO 14040:2006, A.2 gives as two possible approaches to LCA. a) An approach that assigns elementary flows and potential environmental impacts to a specific product system, typically as an account of the history of the product. b) An approach that studies the environmental consequences of possible (future) changes between alternative product systems. Approaches a) and b) have become known as attributional and consequential, respectively, with complementary information accessible in the ILCD handbook.[1] There are numerous pathways to produce hydrogen from various primary energy sources. This document describes the requirements and evaluation methods applied to several hydrogen production pathways of interest: electrolysis, steam methane reforming (with carbon capture and storage), co-production and coal gasification (with carbon capture and storage), auto-thermal reforming (with carbon capture and storage), hydrogen as a co-product in industrial applications and hydrogen from biomass waste as feedstock. This document also considers the GHG emissions due to the conditioning or conversion of hydrogen into different physical forms and chemical carriers: — hydrogen liquefaction; — production, transport and cracking of ammonia as a hydrogen carrier; — hydrogenation, transport and dehydrogenation of liquid organic hydrogen carriers (LOHCs). This document considers the GHG emissions due to hydrogen and/or hydrogen carriers’ transport up to the consumption gate. It is possible that future revisions of this document will consider additional hydrogen production, conditioning, conversion and transport methods. This document applies to and includes every delivery along the supply chain up to the final delivery to the consumption gate (see Figure 2 in the Introduction). This document also provides additional information related to evaluation principles, system boundaries and expected reported metrics in the form of Annexes A to K, that are accessible via the online ISO portal (https://standards.iso.org/iso/ts/19870/ed-1/en).
ISO/FDIS 19870-1 is classified under the following ICS (International Classification for Standards) categories: 13.020.40 - Pollution, pollution control and conservation; 27.075 - Hydrogen technologies. The ICS classification helps identify the subject area and facilitates finding related standards.
ISO/FDIS 19870-1 has the following relationships with other standards: It is inter standard links to ISO/IEC 8824-4:2021, ISO/TS 19870:2023. Understanding these relationships helps ensure you are using the most current and applicable version of the standard.
You can purchase ISO/FDIS 19870-1 directly from iTeh Standards. The document is available in PDF format and is delivered instantly after payment. Add the standard to your cart and complete the secure checkout process. iTeh Standards is an authorized distributor of ISO standards.
Standards Content (Sample)
FINAL DRAFT
International
Standard
ISO/TC 197/SC 1
Hydrogen technologies —
Secretariat: SCC
Methodology for determining
Voting begins on:
the greenhouse gas emissions
2026-01-21
associated with the hydrogen
Voting terminates on:
supply chain —
2026-03-18
Part 1:
Emissions associated with the
production of hydrogen up to the
production gate
Technologies de l'hydrogène — Méthodologie pour déterminer
les émissions de gaz à effet de serre associées à la chaîne
d'approvisionnement en hydrogène —
Partie 1: Émissions associées à la production d'hydrogène
jusqu'au point de production
RECIPIENTS OF THIS DRAFT ARE INVITED TO SUBMIT,
WITH THEIR COMMENTS, NOTIFICATION OF ANY
RELEVANT PATENT RIGHTS OF WHICH THEY ARE AWARE
AND TO PROVIDE SUPPOR TING DOCUMENTATION.
IN ADDITION TO THEIR EVALUATION AS
BEING ACCEPTABLE FOR INDUSTRIAL, TECHNO-
ISO/CEN PARALLEL PROCESSING LOGICAL, COMMERCIAL AND USER PURPOSES, DRAFT
INTERNATIONAL STANDARDS MAY ON OCCASION HAVE
TO BE CONSIDERED IN THE LIGHT OF THEIR POTENTIAL
TO BECOME STAN DARDS TO WHICH REFERENCE MAY BE
MADE IN NATIONAL REGULATIONS.
Reference number
FINAL DRAFT
International
Standard
ISO/TC 197/SC 1
Hydrogen technologies —
Secretariat: SCC
Methodology for determining
Voting begins on:
the greenhouse gas emissions
associated with the hydrogen
Voting terminates on:
supply chain —
Part 1:
Emissions associated with the
production of hydrogen up to the
production gate
Technologies de l'hydrogène — Méthodologie pour déterminer
les émissions de gaz à effet de serre associées à la chaîne
d'approvisionnement en hydrogène —
Partie 1: Émissions associées à la production d'hydrogène
jusqu'au point de production
RECIPIENTS OF THIS DRAFT ARE INVITED TO SUBMIT,
WITH THEIR COMMENTS, NOTIFICATION OF ANY
RELEVANT PATENT RIGHTS OF WHICH THEY ARE AWARE
AND TO PROVIDE SUPPOR TING DOCUMENTATION.
© ISO 2026
IN ADDITION TO THEIR EVALUATION AS
All rights reserved. Unless otherwise specified, or required in the context of its implementation, no part of this publication may
BEING ACCEPTABLE FOR INDUSTRIAL, TECHNO-
ISO/CEN PARALLEL PROCESSING
LOGICAL, COMMERCIAL AND USER PURPOSES, DRAFT
be reproduced or utilized otherwise in any form or by any means, electronic or mechanical, including photocopying, or posting on
INTERNATIONAL STANDARDS MAY ON OCCASION HAVE
the internet or an intranet, without prior written permission. Permission can be requested from either ISO at the address below
TO BE CONSIDERED IN THE LIGHT OF THEIR POTENTIAL
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TO BECOME STAN DARDS TO WHICH REFERENCE MAY BE
MADE IN NATIONAL REGULATIONS.
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Published in Switzerland Reference number
ii
Contents Page
Foreword .iv
Introduction .v
1 Scope . 1
2 Normative references . 1
3 Terms, definitions and abbreviated terms . 2
3.1 Terms related to quantification of the carbon footprint of a product .2
3.2 Terms related to products, product systems and processes .4
3.3 Terms related to life cycle assessment .7
3.4 Terms related to organizations .10
3.5 Terms related to data and data quality .10
3.6 Abbreviated Terms .11
4 Evaluation Methods for GHG emissions .12
4.1 Evaluation Basis . 12
4.1.1 General Principles . 12
4.1.2 Attributional approach . 12
4.1.3 Consequential approach . 12
4.2 Product reporting . 13
4.2.1 Product System Boundary . 13
4.2.2 Selected Cut-Off Criteria .14
4.2.3 Evaluation Elements .14
4.2.4 Evaluation cycle . 15
4.3 Quantification of GHG emissions .16
4.3.1 Process description and data quality .16
4.3.2 Emissions inventory .16
4.3.3 Emissions allocation . 20
4.3.4 CFP calculation.24
4.4 CFP study report .24
5 Critical review .24
Annex A (Normative) Hydrogen Purity .25
Annex B (Informative) Consequential Approach—Examples for Hydrogen Production .29
Annex C (Normative) Feedstocks for Hydrogen Production .33
Annex D (Normative) Hydrogen Production Pathway – Methane Reforming with or without
Carbon Capture and Storage.42
Annex E (Normative) Hydrogen Production Pathway – Water Electrolysis .60
Annex F (Normative) Hydrogen Production Pathway — Chlor-alkali .66
Annex G (Normative) Hydrogen Production Pathway — Steam cracking . 74
Annex H (Normative) Hydrogen Production Pathway — Gasification with or without carbon
capture .81
Annex I (Normative) Hydrogen Production Pathway – Methane pyrolysis.90
Annex J (Normative) Hydrogen Production Pathway — Chemical Looping Water Splitting with
or without carbon capture .98
Annex K (Normative) Hydrogen Production Pathway — Geologic Hydrogen Production .107
Annex L (Normative) Hydrogen Production Pathway — Catalytic Naphtha Reforming .118
Bibliography .125
iii
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 197, Hydrogen technologies, Subcommittee
SC 1, Hydrogen at scale and horizontal energy systems, in collaboration with the European Committee for
Standardization (CEN) Technical Committee CEN/CLC/JTC 6, Hydrogen in energy systems, in accordance with
the Agreement on technical cooperation between ISO and CEN (Vienna Agreement).
This first edition of ISO 19870-1 cancels and replaces ISO/TS 19870:2023, which has been technically
revised.
A list of all parts in the ISO 19870 series can be found on the ISO website.
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.
iv
Introduction
The Paris Agreement was adopted at the UN Climate Change conference (COP21) with the aims of
strengthening the global response to the threat of climate change, restricting global temperature rise to
below 2 C above pre-industrial levels and pursuing efforts to limit the temperature increase to 1,5 °C above
pre-industrial levels. To meet these goals, greenhouse gas (GHG) emissions need to be reduced by about
45 % from 2010 levels by 2030, reaching net zero in 2050 (IPCC, 2018; UNFCCC, 2021).
Initiatives on GHG mitigation rely on the quantification, monitoring, reporting and verification of GHG
emissions and/or removals. International Standards that support the transfer of scientific knowledge into
tools can help in reaching the targets of the Paris Agreement to address climate change.
ISO 14044 defines the requirements and guidelines identified in existing International Standards on life
cycle assessment (LCA). The ISO 14060 series provides clarity and consistency for quantifying, monitoring,
reporting and validating or verifying GHG emissions and removals to support sustainable development
through a low-carbon economy. It also benefits organizations, project proponents and stakeholders
worldwide by providing clarity and consistency on quantifying, monitoring, reporting and validating or
verifying GHG emissions and removals.
ISO 14067 is based on the requirements and guidelines on LCA identified in ISO 14044 and aims to set
specific requirements for the quantification of a carbon footprint (CFP) and a partial CFP. ISO 14067 defines
the principles, requirements and guidelines for the quantification of the carbon footprint of products. Its
aim is to quantify GHG emissions associated with the lifecycle stages of a product, beginning with resource
extraction and raw material sourcing and extending through the production, use and end-of-life stages of
the product.
Figure 1 illustrates the relationship between ISO 14067 and other ISO documents on LCA.
Key
PCR Product category rule
Figure 1 — Relationship between standards beyond the GHG management family of standards
(source ISO 14067)
Hydrogen can be produced from diverse sources including renewables, nuclear and fossil fuels, with or
without carbon capture, utilization and storage (CCUS). Hydrogen can be used to decarbonize numerous
sectors.
A particular challenge is that identical hydrogen molecules can be produced and combined from sources
that have different GHG intensities. Similarly, hydrogen-based fuels and derivatives will be indistinguishable
and can be produced from hydrogen combined with a range of fossil and non-fossil inputs. Indeed, some of
v
the products made from hydrogen (e.g. electricity) can themselves be used in the production of hydrogen.
Accounting standards for different sources of hydrogen along the supply chain (see Figure 2) is important
for creating a market for low-carbon hydrogen, and these standards need to be agreed upon internationally.
Additionally, there is the possibility that consumption gates are not located in proximity to hydrogen
[2]
production gates, requiring hydrogen transport. ISO 14083 gives guidelines for the quantification and
reporting of GHG emissions arising from transport chain operations.
A mutually recognized international framework that is robust, and that avoids miscounting or double
counting of environmental impacts is needed. Such a framework will provide a mutually agreed upon
approach to “guarantees" or “certificates” of origin, and will cover greenhouse gas inputs used for hydrogen
production, conditioning, conversion and transport.
The ISO 19870 series aims at establishing methodologies that should be applied, in line with ISO 14067, to
the specific case of the hydrogen supply chain, covering different production processes and other parts of
the supply chain, such as conditioning hydrogen in different physical states, conversion of hydrogen into
different hydrogen carriers and the subsequent transport up to the consumption gate.
The ISO 19870 series consists of the following parts:
— ISO 19870-1 on emissions associated with the production of hydrogen to production gate;
— ISO 19870-2 on emissions associated with the conditioning and transport of gaseous and liquid hydrogen
up to consumption gate;
— ISO 19870-3 on emissions associated with the production, storage and transport of ammonia up to
delivery gate and the conversion of ammonia into hydrogen;
— ISO 19870-4 on emissions associated with the storage and transport of hydrogen via LOHC.
This document considers the steps up to the production gate.
Figure 2 — Examples of the hydrogen supply chain and coverage of ISO 19870 series with the
possible delivery gates
vi
FINAL DRAFT International Standard ISO/FDIS 19870-1:2026(en)
Hydrogen technologies — Methodology for determining the
greenhouse gas emissions associated with the hydrogen
supply chain —
Part 1:
Emissions associated with the production of hydrogen up to
the production gate
1 Scope
There are numerous pathways to produce hydrogen. This document specifies a methodology for different
hydrogen production pathways for determining the greenhouse gases (GHG) emissions associated with the
hydrogen supply chain from the raw material extraction up to the production gate.
This document considers the GHG emissions associated with hydrogen production up to the production gate.
This document applies to and includes every step within the production process up to the production gate
(see Figure 2 in the Introduction).
NOTE Complementary documents in the ISO 19870 series will consider hydrogen conditioning, conversion and
transport methods.
ISO 14044 requires the goal and scope of a life cycle assessment (LCA) be clearly defined and be consistent
with the intended application. Due to the iterative nature of LCAs, it is possible that the LCA scope needs to
be refined during the study. According to ISO 14040:2006, A.2, the goals and scope of LCAs correspond to
one of the following two approaches:
a) an approach that assigns elementary flows and potential environmental impacts to a specific product
system, typically as an account of the history of the product (see 4.1.2);
b) an approach that studies the environmental consequences of possible (future) changes between
alternative product systems (see 4.1.3).
In this document, approach a) is referred to as an attributional approach, while approach b) is referred to as
[4]
a consequential approach. Complementary information is accessible in the ILCD handbook .
A carbon footprint of a product (CFP) (3.1.2) or partial carbon footprint of a product (3.1.3) as defined
by ISO 14067 can be estimated using either the attributional or the consequential approach, the latter
corresponding to the use of “system expansion via substitution” to avoid allocation when a unit process
yields multiple co-products. This document applies to the CFP for hydrogen production.
2 Normative references
The following documents are referred to in the text in such a way that some or all of their content constitutes
requirements of this document. For dated references, only the edition cited applies. For undated references,
the latest edition of the referenced document (including any amendments) applies.
ISO 14067, Greenhouse gases — Carbon footprint of products — Requirements and guidelines for quantification
ISO 14071, Environmental management — Life cycle assessment — Critical review processes and reviewer
competencies
3 Terms, definitions and abbreviated terms
For the purposes of this document, the following terms and definitions apply.
ISO and IEC maintain terminology databases for use in standardization at the following addresses:
— ISO Online browsing platform: available at https:// www .iso .org/ obp
— IEC Electropedia: available at https:// www .electropedia .org/
3.1 Terms related to quantification of the carbon footprint of a product
3.1.1
allocation
partitioning the input (3.2.7) or output (3.2.9) flows of a process or a product system (3.2.3) between the
product system under study and one or more other product systems
[SOURCE: ISO 14040:2006 and ISO 14040:2006/AMD 1:2020]
3.1.2
carbon footprint of a product
CFP
sum of greenhouse gas emissions (3.1.12) and greenhouse gas removals (3.1.4) in a product system (3.2.3),
expressed as CO equivalent (3.1.10) and based on a life cycle assessment (3.3.5) using the single impact
category of climate change
Note 1 to entry: A CFP can be disaggregated into a set of figures identifying specific GHG emissions (3.1.12) and
removals (3.1.4). A CFP can also be disaggregated into the stages of the life cycle (3.3.4).
Note 2 to entry: The results of the quantification of CFP (3.1.8) are documented in the CFP study report expressed in
mass of CO e (3.1.10) per functional unit (3.2.13).
[SOURCE: ISO 14067:2018, 3.1.1.1]
3.1.3
partial CFP
sum of greenhouse gas emissions (3.1.12) and greenhouse gas removals (3.1.4) of one or more selected
process(es) in a product system (3.2.3) expressed as CO e (3.1.10) and based on the selected stages or
processes within the life cycle (3.3.4)
Note 1 to entry: A partial CFP is based on or compiled from data related to (a) specific process(es) or footprint
information modules (defined in ISO 14026:2017, 3.1.4), which is (are) part of a product system (3.2.3) and can form the
basis for quantification of a carbon footprint of a product (CFP). More detailed information on information modules is
given in ISO 14025:2006, 5.4.
Note 2 to entry: The results of the quantification of the partial CFP are documented in the CFP study report expressed
in mass of CO e (3.1.10) per declared unit.
Note 3 to entry: In this document, partial CFP of hydrogen extends from raw material extraction up to the production
gate.
3.1.4
greenhouse gas removal
GHG removal
withdrawal of a greenhouse gas (3.1.9) from the atmosphere
[SOURCE: ISO 14067:2018, 3.1.2.6]
3.1.5
CFP study
all activities that are necessary to quantify and report the carbon footprint of a product (3.1.2) or a partial
CFP (3.1.3)
[SOURCE: ISO 14067:2018, 3.1.1.4]
3.1.6
product category
group of products that can fulfil equivalent functions
[SOURCE: ISO 14025:2006, 3.12]
3.1.7
production batch
amount of products produced by a device between any two points in time selected by the operator
3.1.8
quantification of CFP
activities that result in the determination of the carbon footprint of a product (3.1.2) or a partial CFP (3.1.3)
Note 1 to entry: Quantification of the carbon footprint of a product (3.1.2) or the partial CFP (3.1.3) is part of the CFP
study (3.1.5)
[SOURCE: ISO 14067:2018, 3.1.1.6]
3.1.9
greenhouse gas
GHG
gaseous constituent of the atmosphere, both natural and anthropogenic, that absorbs and emits radiation
at specific wavelengths within the spectrum of infrared radiation emitted by the Earth’s surface, the
atmosphere and clouds
Note 1 to entry: For a list of greenhouse gases (3.1.9), see the latest IPCC Assessment Report.
Note 2 to entry: Water vapour and ozone, which are anthropogenic as well as natural greenhouse gases (3.1.9), are not
included in the carbon footprint of a product (3.1.2).
Note 3 to entry: The focus of this document is limited to long-lived GHGs and it therefore excludes climate effects due
to changes in surface reflectivity (albedo) and short-lived radiative forcing agents (e.g. black carbon and aerosols).
[SOURCE: ISO 14067:2018, 3.1.2.1]
3.1.10
carbon dioxide equivalent
CO equivalent
CO e
unit for comparing the radiative forcing of a greenhouse gas (3.1.9) to that of carbon dioxide
Note 1 to entry: Mass of a greenhouse gas is converted into CO equivalents by multiplying the mass of the greenhouse
gas (3.1.9) by the corresponding global warming potential (3.1.11) or global temperature change potential (GTP) of that
gas.
Note 2 to entry: In the case of GTP, CO equivalent is the unit for comparing the change in global mean surface
temperature caused by a greenhouse gas to the temperature change caused by carbon dioxide.
[SOURCE: ISO 14067:2018, 3.1.2.2]
3.1.11
global warming potential
GWP
index, based on radiative properties of greenhouse gases (3.1.9) (GHG) measuring the radiative forcing
following a pulse emission of a unit mass of a given GHG in the present-day atmosphere integrated over a
chosen time horizon, relative to that of carbon dioxide (CO )
Note 1 to entry: “Index” as used in this document is a “characterization factor” as defined in ISO 14040:2006, 3.37.
Note 2 to entry: A “pulse emission” is an emission at one point in time.
[SOURCE: ISO 14067:2018, 3.1.2.4]
3.1.12
greenhouse gas emission
GHG emission
release of a greenhouse gas (3.1.9) into the atmosphere
[SOURCE: ISO 14067:2018, 3.1.2.5]
3.1.13
greenhouse gas emission factor
GHG emission factor
coefficient relating activity data with the greenhouse gas emission (3.1.12)
[SOURCE: ISO 14067:2018, 3.1.2.7]
3.1.14
capital goods emission
CAPEX emission
GHG emissions (3.1.12) related to the manufacturing of capital goods
3.1.15
subdivision
virtual subdivision
decomposition of a unit process into physically or virtually distinguishable sub-process steps with the
possibility to collect data exclusively for those sub-processes
3.1.16
hydrogen
gas mainly composed of hydrogen molecules.
Note 1 to entry: A hydrogen molecule is referred to as H .
3.1.17
physical relationship
relation between co-products (3.2.4) based on a chosen physical characteristic (e.g. mass, energy content,
volume)
Note 1 to entry: A physical relationship can be used to:
a) allocate input flows to co-products (3.2.4) based on the specific function the inputs perform in relation to the
individual co-products (3.2.4); and/or,
b) allocate GHG emissions (3.1.12) to the individual co-products (3.2.4),
3.2 Terms related to products, product systems and processes
3.2.1
product
any goods or service
Note 1 to entry: The product can be categorized as follows:
— services (e.g. transport);
— software (e.g. computer program, dictionary);
— hardware (e.g. engine mechanical part);
— processed materials (e.g. lubricant).
3.2.2
product flow
products (3.2.1) entering from or leaving to another product system (3.2.3)
[SOURCE: ISO 14040:2006, 3.27]
3.2.3
product system
collection of unit processes with elementary flows (3.2.14) and product flows (3.2.2), performing one or more
defined functions and which models the life cycle (3.3.4) of a product (3.2.1)
[SOURCE: ISO 14044:2006, 3.28]
3.2.4
co-product
one of two or more products (3.2.1) coming from the same unit process or product system (3.2.3) that is not
considered waste (3.3.15)
[SOURCE: ISO 14040:2006, 3.10, modified — added that a co-product is not considered a waste.]
3.2.5
conditioning
changing the physical conditions (e.g. temperature, pressure) of hydrogen for the purpose of its storage or
transport
Note 1 to entry: In this document, examples are changing the pressure of gaseous hydrogen or liquefying gaseous
hydrogen.
3.2.6
conversion
changing an input characterized by specific physical and chemical characteristics in an output characterized
by different physical and chemical characteristics
Note 1 to entry: If the chemical characteristics are unchanged there is no conversion.
3.2.7
input
product (3.2.1), material or energy flow (3.2.15) that enters a unit process
Note 1 to entry: Products (3.2.1) and materials include raw materials, intermediate products (3.2.8) and co-products
(3.2.4).
[SOURCE: ISO 14040:2006, 3.21]
3.2.8
intermediate product
output from a unit process that is input to other unit processes that requires further transformation within
the system
[SOURCE: ISO 14040:2006, 3.23]
3.2.9
output
product (3.2.1), material or energy flow (3.2.15) that leaves a unit process (3.2.12)
Note 1 to entry: Products (3.2.1) and materials include raw materials, intermediate products (3.2.8), co-products (3.2.4)
and releases (3.4.10).
[SOURCE: ISO 14044:2006, 3.25]
3.2.10
system boundary
boundary based on a set of criteria representing which unit processes (3.2.12) are a part of the system under
study
[SOURCE: ISO 14040:2006/AMD 1:2020, 3.32]
3.2.11
system expansion
concept of expanding the product system (3.2.3) to include additional functions related to the co-products
(3.2.4)
Note 1 to entry: The product system (3.2.3) that is substituted by the co-product (3.2.4) is integrated in the product
system (3.2.3) under study. In practice, the co-products (3.2.4) are compared to other substitutable products, and the
environmental burdens associated with the substituted product(s) are subtracted from the product system (3.2.3)
under study. The identification of this substituted system is done in the same way as the identification of the upstream
system for intermediate product (3.2.8)inputs (3.2.7). See also ISO/TR 14049:2012, 6.4
Note 2 to entry: The application of system expansion (3.2.11) involves an understanding of the market for the co-
products (3.2.4). Decisions about system expansion (3.2.11) can be improved through understanding the way co-
products (3.2.4) compete with other products, as well as the effects of any product substitution upon production
practices in the industries impacted by the co-products (3.2.4).
Note 3 to entry: Can be referred to as system expansion (3.2.11) and also as expanding the system boundary (3.2.10).
[SOURCE: ISO 14044:2006/AMD 2:2020, D.2.1]
3.2.12
process
set of interrelated or interacting activities that transforms inputs (3.2.7) into outputs (3.2.9)
[SOURCE: ISO 14044:2006, 3.11]
3.2.13
functional unit
quantified performance of a product system (3.2.3) for use as a reference unit
Note 1 to entry: As the carbon footprint of a product treats information on a product basis, an additional calculation
based on a declared unit can be presented.
[SOURCE: ISO 14040:2006, 3.20]
3.2.14
elementary flow
material or energy entering the system being studied that has been drawn from the environment without
previous human transformation, or material or energy leaving the system being studied that is released into
the environment without subsequent human transformation
[SOURCE: ISO 14044:2006, 3.12]
3.2.15
energy flow
input (3.2.7) to or output (3.2.9) from a unit process or product system (3.2.3), quantified in energy units
Note 1 to entry: Energy flow that is an input can be called an energy input; energy flow that is an output can be called
an energy output.
[SOURCE: ISO 14040:2006, 3.13]
3.2.16
feedstock
any material input to the hydrogen plant that is not generated at the hydrogen plant itself
Note 1 to entry: A non-exhaustive list can include:
— natural gas (e.g. for steam methane reforming);
— biomethane/renewable natural gas (e.g. for steam methane reforming)
Note 2 to entry: In many European countries, methane sourced from the degradation of biomass under anaerobic
conditions is referred to as “biomethane”. In the United States, it is referred to as “Renewable Natural Gas” or “RNG”.
— biomass;
— coal (e.g. for gasification);
— liquid hydrocarbons (e.g. for catalytic reforming of naphtha);
— biogenic waste (e.g. for gasification);
— non-biogenic waste (e.g. for gasification);
— oxygen (e.g. for autothermal reforming);
— nitrogen
— water (e.g. for water electrolysis);
— steam.
Note 3 to entry: If a hydrogen plant both generates and utilizes a material (e.g. steam), only the portion that is received
by the hydrogen plant from an external source is considered to be a feedstock. For example, steam generated within
the hydrogen plant system boundary for use at the hydrogen plant is not considered to be a feedstock.
3.2.17
production gate
location of the end-outlet of the product (3.2.1) that leaves the production system boundary (3.2.10)
3.2.18
delivery gate
any location where the product (3.2.1) is transferred from one operator to another
3.2.19
consumption gate
location of the final delivery of the product (3.2.1) to its end-use
3.3 Terms related to life cycle assessment
3.3.1
cut-off criteria
specification of the amount of material or energy flow (3.2.15) or the level of significance of greenhouse gas
emissions (3.1.12) associated with unit processes or the product system (3.2.3) to be excluded from a CFP
study (3.1.5)
[SOURCE: ISO 14067:2018, 3.1.4.1, modified — Note 1 to entry omitted.]
3.3.2
evaluation
element within the life cycle interpretation phase intended to establish confidence in the results of the life
cycle assessment (3.3.5)
Note 1 to entry: Evaluation includes completeness check, sensitivity check, consistency check, and any other validation
that may be required according to the goal and scope definition of the study
[SOURCE: ISO 14040:2006]
3.3.3
fugitive emissions
emissions that are not physically controlled but result from the intentional or unintentional releases (3.3.10)
of GHGs (3.1.9)
Note 1 to entry: They commonly arise from the production, processing, transmission, storage, and use of fuels and
other chemicals, often through joints, seals, packing, gaskets, etc.
[SOURCE: 2004 GHG protocol, Chapter 4.6]
3.3.4
life cycle
consecutive and interlinked stages related to a product (3.2.1), from raw material acquisition or generation
from natural resources to end-of-life treatment
Note 1 to entry: “Raw material” is defined in ISO 14040:2006, 3.15.
Note 2 to entry: Stages of a life cycle related to a product include raw material acquisition, production, distribution,
use and end-of-life treatment.
[SOURCE: ISO 14067:2018, 3.1.4.2]
3.3.5
life cycle assessment
LCA
compilation and evaluation of the inputs (3.2.7), outputs (3.2.9) and the potential environmental impacts of a
product (3.2.1) throughout its life cycle (3.3.4)
Note 1 to entry: “Environmental impact” is defined in ISO 14001:2015, 3.2.4.
[SOURCE: ISO 14067:2018, 3.1.4.3, modified — replaced “product system” with “product”]
3.3.6
life cycle inventory analysis
LCI
phase of life cycle assessment (3.3.5) involving the compilation and quantification of inputs (3.2.7) and outputs
(3.2.9) for a product throughout its life cycle (3.3.4)
[SOURCE: ISO 14044:2006, 3.3]
3.3.7
location-based approach
approach using the average GHG emissions intensity of energy and feedstocks (e.g. electricity) supplied for
utilization within a specific region
Note 1 to entry: This uses mostly grid-average emission factors in the location in which energy consumption
occurs.
Note 2 to entry: This definition is derived from ISO 14067:2018, 6.4.9.4.4.
3.3.8
market-based approach
approach to assign the attributes of the product (3.2.1) produced by a specific producer to the product (3.2.1)
consumed by or delivered to a specific user while the product (3.2.1) is physically distributed through a
common infrastructure
Note 1 to entry: These choices (purchasing energy certificates or differentiated electricity product) may be reflected
through contractual arrangements between the user and the producer.
3.3.9
process emissions
direct, including fugitive, emissions within the system boundary (3.2.10), including emissions associated with
waste treatment and disposal, such as, but not limited to, emissions resulting from chemical conversions
and combustion of solid, liquid and/or gaseous fuels or feedstocks
3.3.10
releases
emissions to air and discharges to water and soil
[SOURCE: ISO 14040:2006, 3.30]
3.3.11
sensitivity analysis
systematic procedures for estimating the effects of the choices made regarding methods and data on the
outcome of a CFP study (3.1.5)
[SOURCE: ISO 14067:2018, 3.1.4.7]
3.3.12
sensitivity check
process to determine whether the information obtained from a sensitivity analysis (3.3.11) is relevant for
reaching the conclusions and for giving recommendations
[SOURCE: ISO 14040:2006/AMD1: 2020, 3.43]
3.3.13
waste
substances or objects that the holder intends or is required to dispose of
Note 1 to entry: This definition is taken from the Basel Convention on the Control of Transboundary Movements of
Hazardous Wastes and Their Disposal (22 March 1989), but is not confined in this document to hazardous waste.
[SOURCE: ISO 14040:2006, 3.35]
3.3.14
biogenic waste
biogenic portion of waste (3.3.13)
Note 1 to entry: A non-exhaustive list can include:
— the biogenic portion of municipal solid waste (MSW),
— animal waste,
— sewage sludge,
— food industry residues,
— agricultural residues,
— food and agricultural waste (e.g. home food waste collection)
[5]
— forests that would traditionally be left to decompose naturally .
Note 2 to entry: Whether an output (3.2.9) is considered a waste (3.3.13) or a product (3.2.1) is based on the properties
of the material (e.g. corn stover versus corn kernel). A tree intended for timber harvest may be thinned because of
some perceived defect (e.g. a curved trunk, or relatively diminutive size relative to other trees in the stand). The
valorization of the “waste” material which could be considered “slash and thinning” may change the decision-making
of the forester regarding the disposition of woody material.
3.3.15
non-biogenic waste
non-biogenic portion of waste (3.3.13)
Note 1 to entry: Non-biogenic waste includes content of fossil origin which is not suitable for material recovery. A non-
exhaustive list can include:
— the non-biogenic portion of Municipal Solid Waste (MSW);
— the non-biogenic portion of Industrial Waste;
— plastic waste (3.3.13) of fossil origin (in some jurisdictions (e.g. Japan), this stream is considered to be a part of
MSW).
3.4 Terms related to organizations
3.4.1
organization
person or group of people that has its own functions with responsibilities, authorities and relationships to
achieve its objectives
Note 1 to entry: The concept of organization includes, but is not limited to, sole-trader, company, corporation, firm,
enterprise, authority, partnership, charity or institution, or part or combination thereof, whether incorporated or not,
public or private.
Note 2 to entry: See ISO 14001:2015, Clause 4.
3.5 Terms related to data and data quality
3.5.1
data quality
characteristics of data that relate to their ability to satisfy stated requirements
Note 1 to entry: See ISO 14040.
3.5.2
double counting
allocation of the same GHG emissions and removals occurs more than once
[SOURCE: derived from ISO 14067:2018, 5.12]
3.5.3
primary data
quantified value of a process (3.2.12) or an activity obtained from a direct measurement or a calculation
based on direct measurements
Note 1 to entry: Primary data need not necessarily originate from the product system (3.2.3) under study because
primary data can relate to a different but comparable product system (3.2.3) to that being studied.
Note 2 to entry: Primary data can include greenhouse gas emission factors (3.1.13) and/or greenhouse gas activity data
(defined in ISO 14064-1:2006, 2.11).
[SOURCE: ISO 14067:2018, 3.1.6.1]
3.5.4
secondary data
data which do not fulfil the requirements for primary data (3.5.3)
Note 1 to entry: Secondary data can include data from databases and published literature, default emission factors
from national inventories, calculated data, estimates or other representative data, validated by competent authorities.
Note 2 to entry: Secondary data can include data obtained from proxy processes or estimates.
[SOURCE: ISO 14067:2018, 3.1.6.3]
3.5.5
site-specific data
primary data (3.5.3) obtained within the product system (3.2.3)
Note 1 to entry: All site-specific data are primary data (3.5.3) but not all primary data (3.5.3) are site-specific data
because they may be obtained from a different product system (3.2.3).
Note 2 to entry: Site-specific data include greenhouse gas emissions (3.1.12) from GHG sources as well as permanent
GHG removals by GHG sinks for one specific unit process within a site.
[SOURCE: ISO 14067:2018, 3.1.6.2]
3.5.6
uncertainty
parameter associated with the result of quantification that characterizes the dispersion of the values that
can be reasonably attributed to the quantified amount
Note 1 to entry: Uncertainty can include, for example:
— parameter uncertainty, e.g. greenhouse gas emission (3.1.12) factors, activity data;
— scenario uncertainty, e.g. use stage scenario, end-of-life stage scenario;
— model uncertainty.
Note 2 to entry: Uncertainty information typically specifies quantitative estimates of the likely dispersion of values
and a qualitative description of the likely causes of the dispersion.
[SOURCE: ISO 14067:2018, 3.1.6.4]
3.6 Abbreviated Terms
ATR Auto thermal reforming
CCS CO capture and storage
CCU CO capture and utilization
CFP Carbon footprint of a product
CHP Combined heat and power
CO e Carbon dioxide equivalent
GHG Greenhouse gas
GO Guaranties of origin
GWP Global warming potential
HHV Higher heating value
LCA Life cycle assessment
LCI Life cycle inventory analysis
LHV Lower heating value
NG Natural gas
PSA Pressure swing adsorption
REC Renewable Energy Certificate
SMR Steam methane reforming
4 Evaluation Methods for GHG emissions
4.1 Evaluation Basis
4.1.1 General Principles
The proposed emissions accounting methodology aims to be applicable to a
...
ISO/TC 197/SC 1
Secretariat: SCC
Date: 2025-10-302026-01-06
Hydrogen technologies — Methodology for determining the
greenhouse gas emissions associated with the hydrogen supply chain
— —
Part 1:
Emissions associated with the production of hydrogen up to the
production gate
Technologies de l'hydrogène — Méthodologie pour déterminer les émissions de gaz à effet de serre associées à
la chaîne d'approvisionnement en hydrogène —
Partie 1: Émissions associées à la production d'hydrogène jusqu'au point de production
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ISO/CD 19870-1:2024(E)
FDIS stage
2 © ISO 2024 – All rights reserved
ISO/DISFDIS 19870-1:20252026(en)
All rights reserved. Unless otherwise specified, or required in the context of its implementation, no part of this publication
may be reproduced or utilized otherwise in any form or by any means, electronic or mechanical, including photocopying,
or posting on the internet or an intranet, without prior written permission. Permission can be requested from either ISO
at the address below or ISO’s member body in the country of the requester.
ISO copyright office
CP 401 • Ch. de Blandonnet 8
CH-1214 Vernier, Geneva
Phone: + 41 22 749 01 11
EmailE-mail: copyright@iso.org
Website: www.iso.orgwww.iso.org
Published in Switzerland
ContentsForeword. vii
Introduction . viii
3.1 Terms related to quantification of the carbon footprint of a product . 2
3.2 Terms related to products, product systems and processes . 5
3.3 Terms related to life cycle assessment . 8
3.4 Terms related to organizations .11
3.5 Terms related to data and data quality .11
3.6 Abbreviated Terms .12
4.1 Evaluation Basis .13
4.1.1 General Principles .13
4.1.2 Attributional approach .13
4.1.3 Consequential approach .13
4.2 Product reporting .14
4.2.1 Product System Boundary .14
4.2.2 Selected Cut-Off Criteria .15
4.2.3 Evaluation Elements .16
4.2.4 Evaluation cycle .17
4.3 Quantification of GHG emissions .17
4.3.1 Process description and data quality .17
4.3.2 Emissions inventory .17
4.3.3 Emissions allocation .22
4.3.4 CFP calculation .26
4.4 CFP study report .26
Annex A (Normative) Hydrogen Purity .28
A.1 Background .28
A.2 Method .28
Annex B (Informative) Consequential Approach—Examples for Hydrogen Production .32
B.1 Overview .32
B.2 System expansion to avoid allocation .32
B.3 System expansion to include specific upstream consequences of the production .33
B.4 System expansion to include specific downstream consequences of the production .34
B.5 Macro-economic modelling .34
Annex C Feedstocks for Hydrogen Production (Normative) .37
C.1 Carbon Footprint of Feedstocks .37
C.1.1 General .37
C.1.2 Estimation of the Carbon Footprint .37
C.1.2.1 General . 37
iii
C.1.2.2 Feedstocks not derived from wastes . 37
C.1.2.3 Feedstocks derived from wastes . 37
C.1.2.3.1 General . 37
C.1.2.3.2 System boundary for attributional approach . 38
C.1.2.3.3 System Boundary for Consequential Approach . 39
C.2 Illustrative Examples .42
C.2.1 General .42
C.2.2 Coal as a feedstock for gasification processes .43
C.2.3 Biomass as a feedstock for thermochemical processes .43
C.2.4 Biogas as a feedstock .44
Annex D (Normative) Hydrogen Production Pathway – Methane Reforming with or without
Carbon Capture and Storage .46
D.1 General .46
D.2 Steam Methane Reforming with or without Carbon Capture and Storage .46
SMR/CCS process description and overview .46
D.2.1 46
D.2.1.1 Description . 46
D.2.1.2 Overview . 47
D.2.2 Emission sources and inventory .47
D.2.2.1 General . 47
D.2.2.2 Emission sources . 47
D.2.2.3 Inventory in case of Attributional Approach. 48
D.2.2.3.1 Energy supply and upstream emissions: . 48
D.2.2.3.2 Direct emissions at production: . 48
D.2.2.4 Inventory in case of Consequential Approach . 49
D.2.3 Emission Allocation .49
D.2.3.1 General . 49
D.2.3.2 Allocation: Attributional Approach . 49
D.2.3.2.1 Partitioning . 49
D.2.3.2.1.1 General . 49
D.2.3.2.1.2 Process subdivision . 49
D.2.3.2.1.3 Allocation . 50
D.2.3.3 Allocation: Consequential Approach . 51
D.2.4 Information to be reported .52
D.3 Autothermal Reforming (with or without Carbon Capture and Storage) .55
iv
ISO/DISFDIS 19870-1:20252026(en)
D.3.1 Process description and overview .55
D.3.1.1 Description . 55
D.3.1.2 Overview . 56
D.3.2 Emission sources and inventory .57
D.3.2.1 Emission sources . 57
D.3.2.2 Inventory in case of Attributional Approach. 58
D.3.2.2.1 Energy supply and upstream emissions: . 58
D.3.2.2.2 Direct emissions at production: . 58
D.3.2.2.3 Inventory in case of Consequential Approach . 59
D.3.3 Emission Allocation .59
D.3.3.1 General . 59
D.3.3.2 Allocation: Attributional Approach . 59
D.3.3.2.1 Partitioning . 59
D.3.3.2.1.1 General . 59
D.3.3.2.1.2 Process subdivision: . 59
D.3.3.2.1.3 Allocation . 60
D.3.3.3 Allocation: Consequential Approach . 60
D.3.4 Information to be reported .61
Annex E (Normative) Hydrogen Production Pathway – Water Electrolysis .65
E.1 Electrolysis .65
E.1.1 General .65
E.1.2 Description .65
E.1.3 Overview .65
E.2 Emission Sources and Inventory .66
E.2.1 Emission Sources .66
E.2.2 Inventory in case of Attributional Approach.67
E.2.2.1 General . 67
E.2.2.2 Upstream/ Indirect Emissions . 67
E.2.2.3 Direct Emissions . 67
E.2.3 Inventory in case of Consequential Approach .67
E.3 Emission Allocation .67
E.3.1 General .67
E.3.2 Attributional Approach .67
E.3.3 Consequential Approach .68
E.4 Information to be Reported .68
Annex F (Normative) Hydrogen Production Pathway — Chlor-alkali .70
F.1 Process description and overview .70
F.1.1 Description .70
v
F.1.2 Overview .71
F.2 Emission sources and inventory .72
F.3 Emission Allocation .73
F.3.1 Emission inventory using Attributional Approach .73
F.3.2 Emission inventory using Consequential Approach .74
F.3.2.1 General . 74
F.3.2.2 Facility credit with electricity export . 75
F.3.2.3 Facility credit with steam export . 75
F.4 Information to be reported .76
Annex G (Normative) Hydrogen Production Pathway — Steam cracking .79
G.1 Process description and overview .79
G.1.1 Description .79
G.1.2 Overview .79
G.2 Emission sources and inventory .80
G.2.1 Emission sources .80
G.2.2 Emission inventory .80
G.3 Emission Allocation .81
G.3.1 Emission inventory using Attributional Approach .81
G.3.2 Emission inventory using Consequential Approach [Informative] .82
G.3.2.1 General . 82
G.3.2.2 Facility credit with electricity export . 83
G.3.2.3 Facility credit with steam export . 83
G.4 Information to be reported .84
Annex H (Normative) Hydrogen Production Pathway — Gasification with or without carbon
capture .87
H.1 Overview .87
H.2 Gasification (with or without carbon capture) .87
H.2.1 Process description and overview [informative] .87
H.2.1.1 Description . 87
H.2.1.2 Overview . 88
H.2.2 Emission sources and inventory .89
H.2.2.1 Emission sources[informative] . 89
H.2.2.2 Inventory in case of Attributional Approach. 90
H.2.2.2.1 Energy supply and upstream emissions: . 90
H.2.2.2.2 Direct emissions at production . 90
H.2.2.3 Inventory in case of Consequential Approach . 90
H.2.3 Emission Allocation .90
H.2.3.1 General . 90
H.2.3.2 Allocation: Attributional Approach . 91
vi
ISO/DISFDIS 19870-1:20252026(en)
H.2.3.3 Allocation: Consequential approach . 91
H.2.4 Information to be reported .92
Annex I (Normative) Hydrogen Production Pathway – Methane pyrolysis .96
I.1 Methane pyrolysis .96
I.1.1 Methane pyrolysis process description and overview .96
I.1.1.1 Description . 96
I.1.1.2 Overview . 96
I.1.2 Emission sources and inventory .97
I.1.2.1 Emission sources . 97
I.1.2.2 Inventory in case of Attributional Approach. 98
I.1.2.2.1 Energy supply and upstream emissions. 98
I.1.2.2.2 Direct emissions at production . 98
I.1.2.3 Inventory in case of Consequential Approach . 98
I.1.3 Emission Allocation .98
I.1.3.1 General . 98
I.1.3.2 Allocation: Attributional Approach . 99
I.1.3.3 Allocation: Consequential Approach . 100
I.1.4 Information to be reported . 101
Annex J (Normative) Hydrogen Production Pathway — Chemical Looping Water Splitting with or
without carbon capture . 105
J.1 CLWS/CCS Description . 105
J.2 Emission Sources in CLWS . 106
J.3 Emission inventory . 107
J.3.1 Inventory in case of Attributional Approach. 107
J.3.2 Inventory in case of Consequential Approach . 107
J.4 Emission Allocation for the CLWS Pathway . 107
J.4.1 General . 107
J.4.2 Allocation in case of Attributional Approach . 107
J.4.3 Allocation in case of Consequential Approach . 109
J.5 Information to be Reported . 109
Annex K (Normative) Hydrogen Production Pathway — Geologic Hydrogen Production . 113
K.1 Geologic hydrogen process description and overview . 113
K.1.1 Description . 113
K.1.2 Overview . 114
K.2 Emission sources and inventory . 115
K.2.1 Emission sources . 115
K.2.2 Inventory in case of Attributional Approach. 118
K.2.3 Inventory in case of Consequential Approach . 119
K.3 Emission Allocation . 119
K.3.1 General . 119
K.3.2 Allocation in case of Attributional Approach . 119
K.3.3 Allocation in case of Consequential Approach . 122
K.4 Information to be reported . 122
vii
Annex L (Normative) Hydrogen Production Pathway — Catalytic Naphtha Reforming . 125
L.1 Process Description and Overview . 125
L.1.1 Emission sources and inventory . 126
L.1.1.1 Emission sources [informative] . 126
L.1.1.2 Inventory in case of Attributional Approach. 127
L.1.1.2.1 Energy supply and upstream emissions: . 127
L.1.1.2.2 Direct emissions at production: . 127
L.1.2 Emission Allocation . 127
L.1.2.1 General . 127
L.1.2.2 Allocation: Attributional Approach . 127
L.1.2.3 Allocation: Consequential Approach . 129
L.1.3 Information to be reported . 130
viii
ISO/DISFDIS 19870-1:20252026(en)
Contents
Foreword . x
Introduction . xi
1 Scope . 1
2 Normative references . 1
3 Terms, definitions and abbreviated terms . 2
4 Evaluation Methods for GHG emissions . 13
5 Critical review . 28
Annex A (Normative) Hydrogen Purity . 29
Annex B (Informative) Consequential Approach—Examples for Hydrogen Production . 33
Annex C (Normative) Feedstocks for Hydrogen Production . 39
Annex D (Normative) Hydrogen Production Pathway – Methane Reforming with or without
Carbon Capture and Storage . 54
Annex E (Normative) Hydrogen Production Pathway – Water Electrolysis . 77
Annex F (Normative) Hydrogen Production Pathway — Chlor-alkali . 83
Annex G (Normative) Hydrogen Production Pathway — Steam cracking . 94
Annex H (Normative) Hydrogen Production Pathway — Gasification with or without carbon
capture . 103
Annex I (Normative) Hydrogen Production Pathway – Methane pyrolysis . 113
Annex J (Normative) Hydrogen Production Pathway — Chemical Looping Water Splitting with
or without carbon capture . 123
Annex K (Normative) Hydrogen Production Pathway — Geologic Hydrogen Production . 134
Annex L (Normative) Hydrogen Production Pathway — Catalytic Naphtha Reforming . 147
Bibliography . 156
ix
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.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.htmlwww.iso.org/iso/foreword.html.
This document was prepared by Technical Committee ISO/TC 197, Hydrogen technologies, Subcommittee SC
1, Hydrogen at scale and horizontal energy systems, in collaboration with the European Committee for
Standardization (CEN) Technical Committee CEN/CLC/JTC 6, Hydrogen in energy systems, in accordance with
the Agreement on technical cooperation between ISO and CEN (Vienna Agreement).
This first edition of ISO 19870-1 cancels and replaces ISO/TS 19870:2023, which has been technically revised.
A list of all parts in the ISO 19870 series can be found on the ISO website.
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.
Field Code Changed
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ISO/DISFDIS 19870-1:20252026(en)
Introduction
The Paris Agreement was adopted at the UN Climate Change conference (COP21) with the aims of
strengthening the global response to the threat of climate change, restricting global temperature rise to below
2 C above pre-industrial levels and pursuing efforts to limit the temperature increase to 1,5 °C above pre-
industrial levels. To meet these goals, greenhouse gas (GHG) emissions need to be reduced by about 45 % from
2010 levels by 2030, reaching net zero in 2050 (IPCC, 2018; UNFCCC, 2021).
Initiatives on GHG mitigation rely on the quantification, monitoring, reporting and verification of GHG
emissions and/or removals. International Standards that support the transfer of scientific knowledge into
tools can help in reaching the targets of the Paris Agreement to address climate change.
ISO 14044 [1] defines the requirements and guidelines identified in existing International Standards on life
cycle assessment (LCA). The ISO 14060 series provides clarity and consistency for quantifying, monitoring,
reporting and validating or verifying GHG emissions and removals to support sustainable development
through a low-carbon economy. It also benefits organizations, project proponents and stakeholders
worldwide by providing clarity and consistency on quantifying, monitoring, reporting and validating or
verifying GHG emissions and removals.
ISO 14067 is based on the requirements and guidelines on LCA identified in ISO 14044 and aims to set specific
requirements for the quantification of a carbon footprint (CFP) and a partial CFP. ISO 14067 defines the
principles, requirements and guidelines for the quantification of the carbon footprint of products. Its aim is to
quantify GHG emissions associated with the lifecycle stages of a product, beginning with resource extraction
and raw material sourcing and extending through the production, use and end-of-life stages of the product.
Figure 10 illustrates the relationship between ISO 14067 and other ISO documents on LCA.
Key
PCR Product category rule
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Key
PCR Product category rule
Figure 1 — Relationship between standards beyond the GHG management family of standards
(source ISO 14067)
Hydrogen can be produced from diverse sources including renewables, nuclear and fossil fuels, with or
without carbon capture, utilization and storage (CCUS). Hydrogen can be used to decarbonize numerous
sectors.
A particular challenge is that identical hydrogen molecules can be produced and combined from sources that
have different GHG intensities. Similarly, hydrogen-based fuels and derivatives will be indistinguishable and
can be produced from hydrogen combined with a range of fossil and non-fossil inputs. Indeed, some of the
products made from hydrogen (e.g. electricity) can themselves be used in the production of hydrogen.
Accounting standards for different sources of hydrogen along the supply chain (see Figure 2) will be
fundamental to create0) is important for creating a market for low-carbon hydrogen, and these standards
need to be agreed upon internationally. Additionally, there is the possibility that consumption gates are not
located in proximity to hydrogen production gates, requiring hydrogen transport. ISO 14083 [2]ISO
[ ]
14083 Error! Reference source not found. gives guidelines for the quantification and reporting of GHG
emissions arising from transport chain operations.
A mutually recognized international framework that is robust, and that avoids miscounting or double counting
of environmental impacts is needed. Such a framework will provide a mutually agreed upon approach to
“guarantees" or “certificates” of origin, and will cover greenhouse gas inputs used for hydrogen production,
conditioning, conversion and transport.
The ISO 19870 series aims at establishing methodologies that should be applied, in line with ISO 14067, to the
specific case of the hydrogen supply chain, covering different production processes and other parts of the
supply chain, such as conditioning hydrogen in different physical states, conversion of hydrogen into different
hydrogen carriers and the subsequent transport up to the consumption gate.
The parts of the ISO 19870 multi-standards series areconsists of the following parts:
— ISO 19870-1 on emissions associated with the production of hydrogen to production gate;
— ISO 19870-2 on emissions associated with the conditioning and transport of gaseous and liquid hydrogen
up to consumption gate;
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ISO/DISFDIS 19870-1:20252026(en)
— ISO 19870-3 on emissions associated with the production, storage and transport of ammonia up to
delivery gate and the conversion of ammonia into hydrogen;
— ISO 19870-4 on emissions associated with the storage and transport of hydrogen via LOHC.
This document considers the steps up to the production gate.
Figure 2 — Examples of the hydrogen supply chain and coverage of ISO 19870 series with the
possible delivery gates
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DRAFT International Standard ISO/DIS 19870-1:2025(en)
Hydrogen technologies — Methodology for determining the
greenhouse gas emissions associated with the hydrogen supply chain
— —
Part 1:
Emissions associated with the production of hydrogen up to the
production gate
1 Scope
There are numerous pathways to produce hydrogen. This document specifies a methodology for different
hydrogen production pathways for determining the greenhouse gases (GHG) emissions associated with the
hydrogen supply chain from the raw material extraction up to the production gate.
This document considers the GHG emissions associated with hydrogen production up to the production gate.
This document applies to and includes every step within the production process up to the production gate
(see Figure 20 in the Introduction).
NOTE Complementary documents in the ISO 19870 series will consider hydrogen conditioning, conversion and
transport methods.
ISO 14044 [1] requires the goal and scope of a life cycle assessment (LCA) be clearly defined and be consistent
with the intended application. Due to the iterative nature of LCAs, it is possible that the LCA scope needs to be
refined during the study. According to ISO 14040:2006, Annex A2 [3]A.2, the goals and scope of LCAs
correspond to one of
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