SIST EN ISO 19870-1:2026

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 19870-1:2026)

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:
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);
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 a consequential approach. Complementary information is accessible in the ILCD handbook[4].
A carbon footprint of a product (CFP) (3.1.2) or partial CFP (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.

Wasserstofftechnologien - Methodik zur Bestimmung der Treibhausgasemissionen der Wasserstoffversorgungskette - Teil 1: Emissionen aus der Wasserstofferzeugung bis zum Produktionsgate (ISO 19870-1:2026)

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 (ISO 19870-1:2026)

Il existe de nombreuses voies pour produire de l'hydrogène. Le présent document spécifie une méthodologie pour différentes voies de production d'hydrogène afin de déterminer les émissions de gaz à effet de serre (GES) associées à la chaîne d'approvisionnement en hydrogène depuis l'extraction des matières premières jusqu'au point de production.
Le présent document prend en compte les émissions de GES associées à la production d'hydrogène jusqu'au point de production. Le présent document s'applique et comprend toutes les étapes du processus de production jusqu'au point de production (voir Figure 2 dans l'Introduction).
NOTE            Les documents complémentaires de la série ISO 19870 considéreront les méthodes de conditionnement, de conversion et de transport de l'hydrogène.
L'ISO 14044 exige que le but et le domaine d'application d'une analyse du cycle de vie (ACV) soient clairement définis et soient cohérents avec l'application prévue. En raison de la nature itérative des ACV, il est possible que le domaine d'application des ACV ait besoin d'être affiné pendant l'étude. Selon l'ISO 14040:2006, A.2, les objectifs et le domaine d'application des ACV correspondent à l'une des deux approches suivantes:
une approche qui attribue des flux élémentaires et des potentiels impacts environnementaux à un système de produits spécifique, généralement en tant que compte-rendu de l'historique du produit. (voir 4.1.2);
une approche qui étudie les conséquences environnementales d'éventuels (futurs) changements entre systèmes de produits alternatifs (voir 4.1.3).
Dans le présent document, l'approche a) est appelée approche attributionnelle, tandis que l'approche b) est appelée approche conséquentielle. Des informations complémentaires sont accessibles dans le manuel ILCD[4].
L'empreinte carbone d'un produit (ECP) (3.1.2) ou l'empreinte ECP partielle (3.1.3) telle que définie par l'ISO 14067 peut être estimée à l'aide de l'approche attributionnelle ou de l'approche conséquentielle, cette dernière correspondant à l'utilisation de l'«élargissement du système par substitution» pour éviter l'allocation lorsqu'un processus élémentaire produit plusieurs coproduits. Le présent document s'applique à l'ECP pour la production d'hydrogène.

Tehnologije vodika - Metodologija za določanje emisij toplogrednih plinov, povezanih z dobavno verigo vodika - 1. del: Emisije, povezane s proizvodnjo vodika do proizvodnega praga (ISO 19870-1:2026)

Obstaja veliko poti za proizvodnjo vodika. Ta dokument določa metodologijo za različne poti proizvodnje vodika za določanje emisij toplogrednih plinov (GHG) povezanih z verigo oskrbe z vodikom od pridobivanja surovin do proizvodnega praga.
Ta dokument obravnava emisije GHG povezane s proizvodnjo vodika do proizvodnega praga. Dokument se uporablja za in vključuje vsak korak znotraj proizvodnega procesa do proizvodnega praga (glej sliko 2 v uvodu).
OPOMBA Dopolnilni dokumenti v seriji ISO 19870 bodo obravnavali kondicioniranje vodika, metode pretvorbe in transporta.
ISO 14044 zahteva, da so cilj in obseg ocene življenjskega cikla (LCA) jasno opredeljeni in skladni z nameravano uporabo. Zaradi iterativne narave LCA je možno, da je treba obseg LCA med študijo izpopolniti. V skladu z ISO 14040:2006, A.2, cilji in obseg LCA ustrezajo enemu od naslednjih dveh pristopov:
- pristop, ki dodeljuje osnovne tokove in potencialne vplive na okolje določenemu sistemu izdelkov, običajno kot prikaz zgodovine izdelka (glej 4.1.2);
- pristop, ki preučuje okoljske posledice možnih (prihodnjih) sprememb med alternativnimi sistemi izdelkov (glej 4.1.3).
V tem dokumentu se pristop a) imenuje atribucijski pristop, medtem ko se pristop b) imenuje posledični pristop. Dopolnilne informacije so dostopne v priročniku ILCD[4].
Ogljični odtis izdelka (CFP) (3.1.2) ali delni CFP (3.1.3), kot ga določa ISO 14067, se lahko oceni z uporabo bodisi atribucijskega bodisi posledičnega pristopa, pri čemer slednji ustreza uporabi "razširitve sistema preko nadomestitve" za izogibanje alokaciji, ko enotni proces proizvaja več soproizvodov. Ta dokument se uporablja za CFP pri proizvodnji vodika.

General Information

• Status: Published
• Public Enquiry End Date: 02-Jul-2025
• Publication Date: 15-Jun-2026
• ICS: 13.020.40 - Pollution, pollution control and conservation
• ICS: 27.075 - Hydrogen technologies
• Technical Committee: DPL - Gas supply
• Current Stage: 6060 - National Implementation/Publication (Adopted Project)
• Start Date: 07-May-2026
• Due Date: 12-Jul-2026
• Completion Date: 16-Jun-2026
• Ref Project: EN ISO 19870-1:2026 - 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 19870-1:2026)

Relations

• Refers: SIST ISO 14067:2023 - Greenhouse gases — Carbon footprint of products — Requirements and guidelines for quantification
• Effective Date: 06-May-2026

Overview

SIST EN ISO 19870-1:2026 establishes a standardized methodology for determining greenhouse gas (GHG) emissions in the hydrogen supply chain, specifically focusing on emissions associated with hydrogen production up to the production gate. Developed by the Slovenski inštitut za standardizacijo (SIST) and harmonized as ISO 19870-1:2026, this document enables accurate and consistent carbon accounting of various hydrogen production pathways, supporting global efforts to assess and manage the environmental impacts of hydrogen technologies.

By following principles outlined in ISO 14044 for life cycle assessment (LCA), this standard ensures that industries, regulators, and stakeholders can evaluate the carbon footprint of hydrogen from raw material extraction through the entire production process, right to the point where hydrogen is ready for conditioning, conversion, or distribution. This framework is crucial for supporting low-carbon hydrogen certification, sustainability reporting, and the broader goals of climate change mitigation.

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Key Topics

• Comprehensive LCA Methodology: Specifies how to define system boundaries, select data, evaluate processes, and allocate emissions for all production steps leading up to the hydrogen production gate.
• Attributional vs. Consequential Approaches: Guides users in selecting between the attributional (historical account) and consequential (future-oriented) LCA techniques, as defined in ISO 14040.
• Carbon Footprint of Hydrogen: Defines requirements for calculating total or partial carbon footprint using established international criteria, supporting robust and transparent GHG quantification.
• Multiple Hydrogen Pathways: Includes methodological provisions for assessing emissions from diverse sources such as steam methane reforming, water electrolysis, biomass gasification, and more, reflecting the complexity of modern hydrogen production.
• Alignment with International Initiatives: Integrates guidance from ISO 14067 and references best practices for carbon reporting, ensuring consistency with international GHG management standards.
• Critical Review and Data Quality: Emphasizes data transparency, cut-off criteria, and the importance of a critical review process in LCA studies, as outlined in ISO 14044 and ISO/TS 14071.

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Applications

The methodology detailed in SIST EN ISO 19870-1:2026 is designed for wide adoption across the hydrogen sector, enabling:

• Certification and Labeling: Provides the scientific basis for low-carbon or renewable hydrogen certification and guarantees of origin, essential for building credible green hydrogen markets.
• Regulatory Compliance: Supports policy-makers and regulators in setting emission limits or incentives based on scientifically robust GHG accounting.
• Sustainability Reporting: Enables companies to report hydrogen’s carbon footprint according to globally accepted protocols, improving transparency for investors and customers.
• Technology Comparison: Facilitates decision-making by allowing fair, comparable assessment of alternative hydrogen production routes, guiding investment and innovation.
• Supply Chain Management: Assists industry stakeholders in identifying emission hotspots and efficiency opportunities within complex hydrogen supply chains.
• International Trade: Encourages harmonized emission calculations, reducing market barriers and supporting cross-border hydrogen trade aligned with international climate commitments.

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Related Standards

• ISO 14040: Environmental management - Life cycle assessment - Principles and framework
• ISO 14044: Environmental management - Life cycle assessment - Requirements and guidelines
• ISO 14067: Greenhouse gases - Carbon footprint of products - Requirements and guidelines for quantification
• ISO 14083: Greenhouse gases - Quantification and reporting of GHG emissions arising from transport chain operations
• ISO/TS 14071: Environmental management - LCA - Critical review processes and reviewer competencies

Complementary documents in the ISO 19870 series will address GHG emissions from hydrogen conditioning, conversion, and transport, offering coverage of the full hydrogen supply chain. The methodology is aligned with leading LCA and GHG reporting standards, ensuring broad applicability alongside other international guidelines for environmental performance evaluation.

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Keywords: hydrogen supply chain, greenhouse gas emissions, carbon footprint, ISO 19870-1, hydrogen production, life cycle assessment, GHG quantification, sustainability, low-carbon hydrogen, environmental standards, ISO 14044, ISO 14067, renewable hydrogen, hydrogen technologies.

Standards Content (Sample)

SLOVENSKI STANDARD
01-julij-2026
Tehnologija vodika - Metodologija za določanje emisij toplogrednih plinov v
povezavi z vodikovo oskrbovalno verigo - 1. del: Emisije, povezane s proizvodnjo
vodika do izstopa iz proizvodnega obrata (ISO 19870-1:2026)
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 19870-1:2026)
Wasserstofftechnologien - Methodik zur Bestimmung der Treibhausgasemissionen der
Wasserstoffversorgungskette - Teil 1: Emissionen aus der Wasserstofferzeugung bis
zum Produktionsgate (ISO 19870-1:2026)
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 (ISO
19870-1:2026)
Ta slovenski standard je istoveten z: EN ISO 19870-1:2026
ICS:
13.020.40 Onesnaževanje, nadzor nad Pollution, pollution control
onesnaževanjem in and conservation
ohranjanje
27.075 Tehnologija vodika Hydrogen technologies
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

EUROPEAN STANDARD EN ISO 19870-1

NORME EUROPÉENNE
EUROPÄISCHE NORM
April 2026
ICS 27.075; 13.020.40
English version
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
19870-1:2026)
Technologies de l'hydrogène - Méthodologie pour Wasserstofftechnologien - Methodik zur Bestimmung
déterminer les émissions de gaz à effet de serre der Treibhausgasemissionen der
associées à la chaîne d'approvisionnement en Wasserstoffversorgungskette - Teil 1: Emissionen aus
hydrogène - Partie 1: Émissions associées à la der Wasserstofferzeugung bis zum Produktionsgate
production d'hydrogène jusqu'au point de production (ISO 19870-1:2026)
(ISO 19870-1:2026)
This European Standard was approved by CEN on 19 April 2026.

CEN and CENELEC members are bound to comply with the CEN/CENELEC Internal Regulations which stipulate the conditions for
giving this European Standard the status of a national standard without any alteration. Up-to-date lists and bibliographical
references concerning such national standards may be obtained on application to the CEN-CENELEC Management Centre or to
any CEN and CENELEC member.
This European Standard exists in three official versions (English, French, German). A version in any other language made by
translation under the responsibility of a CEN and CENELEC member into its own language and notified to the CEN-CENELEC
Management Centre has the same status as the official versions.

CEN and CENELEC members are the national standards bodies and national electrotechnical committees of Austria, Belgium,
Bulgaria, Croatia, Cyprus, Czech Republic, Denmark, Estonia, Finland, France, Germany, Greece, Hungary, Iceland, Ireland, Italy,
Latvia, Lithuania, Luxembourg, Malta, Netherlands, Norway, Poland, Portugal, Republic of North Macedonia, Romania, Serbia,
Slovakia, Slovenia, Spain, Sweden, Switzerland, Türkiye and United Kingdom.

CEN-CENELEC Management Centre:
Rue de la Science 23, B-1040 Brussels
© 2026 CEN/CENELEC All rights of exploitation in any form and by any means Ref. No. EN ISO 19870-1:2026 E
reserved worldwide for CEN national Members and for
CENELEC Members.
Contents Page
European foreword . 3

European foreword
This document (EN ISO 19870-1:2026) has been prepared by Technical Committee ISO/TC 197
"Hydrogen technologies" in collaboration with Technical Committee CEN-CENELEC/ JTC 6 “Hydrogen in
energy systems” the secretariat of which is held by NEN.
This European Standard shall be given the status of a national standard, either by publication of an
identical text or by endorsement, at the latest by October 2026, and conflicting national standards shall
be withdrawn at the latest by October 2026.
Attention is drawn to the possibility that some of the elements of this document may be the subject of
patent rights. CEN-CENELEC shall not be held responsible for identifying any or all such patent rights.
Any feedback and questions on this document should be directed to the users’ national standards
body/national committee. A complete listing of these bodies can be found on the CEN and CENELEC
websites.
According to the CEN-CENELEC Internal Regulations, the national standards organizations of the
following countries are bound to implement this European Standard: Austria, Belgium, Bulgaria,
Croatia, Cyprus, Czech Republic, Denmark, Estonia, Finland, France, Germany, Greece, Hungary, Iceland,
Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, Netherlands, Norway, Poland, Portugal, Republic of
North Macedonia, Romania, Serbia, Slovakia, Slovenia, Spain, Sweden, Switzerland, Türkiye and the
United Kingdom.
Endorsement notice
The text of ISO 19870-1:2026 has been approved by CEN-CENELEC as EN ISO 19870-1:2026 without
any modification.
International
Standard
ISO 19870-1
First edition
Hydrogen technologies —
2026-04
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
Reference number
ISO 19870-1:2026(en) © ISO 2026

ISO 19870-1:2026(en)
© ISO 2026
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: [phone]
Email: [e-mail]
Website: www.iso.org
Published in Switzerland
ii
ISO 19870-1:2026(en)
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
ISO 19870-1:2026(en)
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
ISO 19870-1:2026(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 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
ISO 19870-1:2026(en)
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
International Standard ISO 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 CFP (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
ISO 19870-1:2026(en)
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]

ISO 19870-1:2026(en)
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]

ISO 19870-1:2026(en)
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:

ISO 19870-1:2026(en)
— 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]

ISO 19870-1:2026(en)
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]

ISO 19870-1:2026(en)
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.]

ISO 19870-1:2026(en)
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.

ISO 19870-1:2026(en)
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 .

ISO 19870-1:2026(en)
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 dimi
...