ISO 6338:2023
(Main)Method to calculate GHG emissions at LNG plant
Method to calculate GHG emissions at LNG plant
This document provides a method to calculate the GHG emissions from an LNG liquefaction plant, onshore or offshore. The frame of this document ranges from the inlet flange of the LNG plant’s inlet facilities up to and including the offloading arms to truck, ship or railcar loading. The upstream supply of gas up to the inlet flange of the inlet facilities and the distribution of LNG downstream of the loading arms are only covered in general terms. This document covers: — all facilities associated with producing LNG, including reception facilities, condensate unit (where applicable), pre-treatment units (including but not limited to acid gas removal, dehydration, mercury removal, heavies removal), LPG extraction and fractionation (where applicable), liquefaction, LNG storage and loading, Boil-Off-Gas handling, flare and disposal systems, imported electricity or on-site power generation and other plant utilities and infrastructure (e.g. marine and transportation facilities). — natural gas liquefaction facilities associated with producing other products (e.g. domestic gas, condensate, LPG, sulphur, power export) to the extent required to allocate GHG emissions to the different products. — all GHG emissions associated with producing LNG. These emissions spread across scope 1, scope 2 and scope 3 of the responsible organization. Scope 1, 2 and 3 are defined in this document. All emissions sources are covered including flaring, combustion, cold vents, process vents, fugitive leaks and emissions associated with imported energy. The LNG plant is considered “under operation”, including emissions associated with initial start-up, maintenance, turnaround and restarts after maintenance or upset. The construction, commissioning, extension and decommissioning phases are excluded from this document but can be assessed separately. The emissions resulting from boil-off gas management during loading of the ship or any export vehicle are covered by this document. The emissions from a ship at berth, e.g. mast venting are not covered by this document. This document describes the allocation of GHG emissions to LNG and other hydrocarbon products where other products are produced (e.g. LPG, domestic gas, condensates, sulphur, etc.). This document defines preferred units of measurement and necessary conversions. This document also recommends instrumentation and estimations methods to monitor and report GHG emissions. Some emissions are measured and some are estimated. This document is applicable to the LNG industry. Applications include the provision of method to calculate GHG emissions through a standardized and auditable method, a means to determine their carbon footprint.
Méthode pour calculer les émissions de GES dans les usines GNL
Le présent document fournit une méthode pour calculer les émissions de GES d'une usine de liquéfaction GNL, à terre ou en mer. Le cadre du présent document s’étend des installations d'entrée de l'usine GNL aux bras de déchargement pour le chargement de camion, bateau ou wagon. L’approvisionnement en gaz en amont jusqu'à la bride d'entrée des installations d'entrée et la distribution de GNL en aval des bras de chargement ne sont couverts que de manière générale. Le présent document couvre: — toutes les installations associées à la production de GNL, cela inclut les installations de réception, l'unité de condensats (le cas échéant), les unités de prétraitement (comprenant, entre autres, l'élimination des gaz acides, la déshydratation, l'élimination du mercure, l'élimination des hydrocarbures lourds), l'extraction et le fractionnement du GPL (le cas échéant), la liquéfaction, le stockage et le chargement du GNL, la gestion des gaz d'évaporation, les systèmes de torchage et de traitements des déchets, l'électricité importée ou la production d'électricité sur site et les autres utilités et infrastructures de l'usine (par exemple, les installations maritimes et de transport). — les installations de liquéfaction du gaz naturel associées à la production d'autres produits (tels que le gaz domestique, le condensat, le GPL, le soufre, l'exportation d'électricité) afin de pouvoir allouer les émissions de GES aux différents produits. — les émissions de GES associées à la production de GNL. Ces émissions se répartissent entre la catégorie 1, la catégorie 2 et la catégorie 3 de l'organisme responsable. Les catégories 1, 2 et 3 sont définies dans le présent document. Toutes les sources d'émission sont couvertes, y compris le torchage, la combustion, les évents froids, les évents de procédé, les fuites fugitives et les émissions associées à l'énergie importée. L'usine GNL est considérée comme étant «en exploitation», cela inclut les émissions associées à la mise en service, au démarrage initial, à la maintenance, à la révision et aux redémarrages après une maintenance ou perturbation. Les phases de construction, de mise en service, d'extension et d'abandon sont exclues, mais peuvent être évaluées séparément. Les émissions résultant de la gestion des gaz d'évaporation pendant le chargement d'un navire ou de tout véhicule d'exportation sont couvertes. Les émissions d'un navire à quai, par exemple le dégazage par le mât, ne sont pas couvertes dans le présent document. Le présent document décrit l'allocation des émissions de GES au GNL et aux autres produits d'hydrocarbures lorsque d'autres produits sont produits (par exemple, GPL, gaz domestique, condensats, soufre, etc.). Le présent document définit les unités de mesure privilégiées et les conversions nécessaires. Le présent document recommande également l'instrumentation et les méthodes d'estimation pour surveiller et déclarer les émissions de GES. Certaines émissions sont mesurées et d'autres estimées. Le présent document est applicable à l'industrie du GNL. Les applications incluent la fourniture d'une méthode pour calculer les émissions de GES à travers une méthode standardisée et auditable, un moyen de déterminer leur empreinte carbone.
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INTERNATIONAL ISO
STANDARD 6338
First edition
2023-05
Method to calculate GHG emissions at
LNG plant
Méthode pour calculer les émissions de GES dans les usines GNL
Reference number
ISO 6338:2023(E)
© ISO 2023
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ISO 6338:2023(E)
COPYRIGHT PROTECTED DOCUMENT
© ISO 2023
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
Email: copyright@iso.org
Website: www.iso.org
Published in Switzerland
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ISO 6338:2023(E)
Contents Page
Foreword .v
Introduction . vi
1 Scope . 1
2 Normative references . 1
3 Terms and definitions . 2
4 Principles . 3
4.1 General . 3
4.2 Relevance . 3
4.3 Completeness . 4
4.4 Consistency . 4
4.5 Transparency . 4
4.6 Accuracy . 4
4.7 Conservativeness. 4
5 GHG inventory boundaries .4
6 Quantification of GHG emissions . 5
6.1 Identification of GHG sources and quantification approach . 5
6.1.1 General . 5
6.1.2 Emissions from fuel combustion . . 6
6.1.3 Emissions from flaring and venting . 6
6.1.4 Fugitive emissions . 7
6.1.5 Emissions associated with imported energy, utilities, and consumables . 7
6.2 Calculation of GHG emissions . 8
6.2.1 Requirements and guidance . 8
6.2.2 GHG inventory . . 9
6.2.3 GHG quantification methods for fuel combustion . 11
6.2.4 GHG quantification methods for flaring and venting . 11
6.2.5 GHG Quantification methods for fugitive emissions . 11
6.2.6 Quantification methods for emissions from imported energy, utilities, and
consumables . 12
6.2.7 Relevant period and frequency .12
6.3 Preferred units . 13
6.4 Allocation . 13
6.4.1 Principles .13
6.4.2 Methodology . . 13
6.5 Carbon capture . 16
6.5.1 Opportunities for carbon capture: . 16
6.5.2 Quantification of carbon capture benefit . 16
7 GHG inventory quality management .16
7.1 General . 16
7.2 GHG Emission Calculation approach . 17
7.3 Estimation of inventory uncertainties . 17
7.4 Procedures for documentation and archiving . 17
7.5 Quality Control . 17
7.6 Quality Assurance . 18
8 GHG reporting .19
8.1 General . 19
8.2 Additional information. 19
8.3 GHG emission reduction . 19
8.4 Carbon offset and emission trading . 20
9 Independent review . .20
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ISO 6338:2023(E)
Annex A (informative) Conversion factors for reference .21
Annex B (informative) International initiatives on climate ambitions .22
Annex C (informative) Example allocation calculation .24
Bibliography .30
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ISO 6338:2023(E)
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 documents 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).
Attention is drawn to the possibility that some of the elements of this document may be the subject of
patent rights. ISO shall not be held responsible for identifying any or all such patent rights. Details of
any patent rights identified during the development of the document will be in the Introduction and/or
on the ISO list of patent declarations received (see www.iso.org/patents).
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 67, Oil and gas industries including lower
carbon energy, Subcommittee SC 9, Production, transport and storage facilities for cryogenic liquefied
gases.
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.
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ISO 6338:2023(E)
Introduction
Natural gas will play a key role in the energy transition (e.g. by replacing coal to produce electricity)
and the use of LNG to transport natural gas is expected to increase. The process of liquefying natural
gas is energy-intensive. Gas producers are increasingly accountable for their greenhouse gas (GHG)
emissions and the ambition to reduce them. Furthermore, there is an emerging marketing demand for
GHG data to enable commercial mechanisms such as offsetting to be utilized.
There is no standardized and auditable methodology to calculate the carbon footprint of the whole LNG
chain (including but not limited to the well, upstream treatment, transportation, liquefaction, shipping,
regasification and end user distribution). Various standards indicate possible approaches but these are
not consistent in their results or easily applicable.
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INTERNATIONAL STANDARD ISO 6338:2023(E)
Method to calculate GHG emissions at LNG plant
1 Scope
This document provides a method to calculate the GHG emissions from an LNG liquefaction plant,
onshore or offshore.
The frame of this document ranges from the inlet flange of the LNG plant’s inlet facilities up to and
including the offloading arms to truck, ship or railcar loading. The upstream supply of gas up to the
inlet flange of the inlet facilities and the distribution of LNG downstream of the loading arms are only
covered in general terms.
This document covers:
— all facilities associated with producing LNG, including reception facilities, condensate unit (where
applicable), pre-treatment units (including but not limited to acid gas removal, dehydration, mercury
removal, heavies removal), LPG extraction and fractionation (where applicable), liquefaction, LNG
storage and loading, Boil-Off-Gas handling, flare and disposal systems, imported electricity or on-
site power generation and other plant utilities and infrastructure (e.g. marine and transportation
facilities).
— natural gas liquefaction facilities associated with producing other products (e.g. domestic gas,
condensate, LPG, sulphur, power export) to the extent required to allocate GHG emissions to the
different products.
— all GHG emissions associated with producing LNG. These emissions spread across scope 1, scope
2 and scope 3 of the responsible organization. Scope 1, 2 and 3 are defined in this document. All
emissions sources are covered including flaring, combustion, cold vents, process vents, fugitive
leaks and emissions associated with imported energy.
The LNG plant is considered “under operation”, including emissions associated with initial start-up,
maintenance, turnaround and restarts after maintenance or upset. The construction, commissioning,
extension and decommissioning phases are excluded from this document but can be assessed separately.
The emissions resulting from boil-off gas management during loading of the ship or any export vehicle
are covered by this document. The emissions from a ship at berth, e.g. mast venting are not covered by
this document.
This document describes the allocation of GHG emissions to LNG and other hydrocarbon products
where other products are produced (e.g. LPG, domestic gas, condensates, sulphur, etc.).
This document defines preferred units of measurement and necessary conversions.
This document also recommends instrumentation and estimations methods to monitor and report GHG
emissions. Some emissions are measured and some are estimated.
This document is applicable to the LNG industry.
Applications include the provision of method to calculate GHG emissions through a standardized and
auditable method, a means to determine their carbon footprint.
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.
1
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ISO 6338:2023(E)
ISO 14044, Environmental management — Life cycle assessment — Requirements and guidelines
ISO 14064-1, Greenhouse gases — Part 1: Specification with guidance at the organization level for
quantification and reporting of greenhouse gas emissions and removals
API Consistent Methodology for Estimating Greenhouse Gas Emissions from Liquefied Natural Gas (LNG)
Operations
3 Terms and definitions
For the purposes of this document, the terms and definitions given in ISO 14064-1 and the following
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
facility
single installation, set of installations or production processes (stationary or mobile), which can be
defined within a single geographical boundary, organizational unit or production process
[SOURCE: ISO 14064-1:2018, 3.4.1]
3.2
global warming potential
GWP
ratio of the time-integrated radiative forcing (warming effect) from the instantaneous release of 1 kg of
the GHG relative to that from the release of 1 kg of CO2
3.3
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 GHGs, see the 6th Intergovernmental Panel on Climate Change (IPCC) Assessment
Report.
Note 2 to entry: Water vapour and ozone are anthropogenic as well as natural GHGs, but are not included as
recognized GHGs due to difficulties, in most cases, in isolating the human-induced component of global warming
attributable to their presence in the atmosphere.
[SOURCE: ISO 14064-1:2018, 3.1.1]
3.4
organizational boundary
grouping of activities or facilities in which an organization exercises operational or financial control or
has an equity share
[SOURCE: ISO 14064-1:2018, 3.4.7]
3.5
reporting boundary
grouping of greenhouse gas (GHG) emission or GHG removals reported from within the organizational
boundary, as well as those significant indirect emissions that are a consequence of the organization’s
operations and activities
[SOURCE: ISO 14064-1:2018, 3.4.8]
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ISO 6338:2023(E)
3.6
scope 1
direct greenhouse gas emissions
direct GHG emissions
emissions coming from sources that are owned or controlled by the facility
Note 1 to entry: This can be the emissions that are directly created by product fabrication or synthesis, for
example, combustion fumes from a refinery.
3.7
scope 2
indirect greenhouse gas emissions from purchased and consumed energy
indirect GHG emissions from purchased and consumed energy
emissions from the generation of imported electricity, steam, and heating/cooling consumed by the
facillity
Note 1 to entry: These emissions physically occur at the facility where electricity, steam and cooling or heating
are generated but as a user of the energy, the consuming party is still responsible for the greenhouse gas
emissions that are being created.
3.8
scope 3
other indirect greenhouse gas emissions
other indirect GHG emissions
emissions from sources that are not owned and not directly controlled by the facility
Note 1 to entry: However, they are related to the company’s activities. This is usually considered to be the
supply chain of the company, so emissions caused by vendors within the supply chain, outsourced activities, and
employee travel and commute. In many industries, other indirect GHG emissions account for the biggest amount
of GHG emissions. This is due to the fact that in today’s economy, many tasks are outsourced and few companies
own the entire value chain of their products.
3.9
quality assurance
QA
planned system of review procedures conducted by personnel not directly involved in the inventory
compilation/development process
3.10
quality control
QC
planned system of review procedures conducted by personnel not directly involved in the inventory
compilation/development process
4 Principles
4.1 General
The application of the following principles is fundamental to guarantee that GHG calculations are a true
and fair account.
4.2 Relevance
Use data, methods, criteria, and assumptions that are appropriate for the intended use of reported
information. The quantification and reporting of GHG emissions shall include only information that
users — both internal and external to the plant — need for their decision-making. This information
shall thus fit the intended purpose of the GHG project and meet the expectations or requirements of
its users. Data, methods, criteria, and assumptions that are misleading or that do not conform to this
document are not relevant and shall not be included.
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ISO 6338:2023(E)
4.3 Completeness
Consider all relevant information that can affect the accounting and quantification of GHG reductions,
and complete all requirements. All relevant information shall be included in the quantification of GHG
emissions. A GHG monitoring plan shall also specify how all data relevant to quantifying GHG reductions
will be collected.
4.4 Consistency
Use data, methods, criteria, and assumptions that allow meaningful and valid comparisons. The credible
quantification of GHG emissions requires that methods and procedures are always in the same manner,
that the same criteria and assumptions are used to evaluate significance and relevance, and that any
data collected and reported will be compatible enough to allow meaningful comparisons over time.
4.5 Transparency
Provide clear and sufficient information for reviewers to assess the credibility and reliability of GHG
emissions claims. Transparency is critical for quantifying and reporting GHG reductions, particularly
given the flexibility and policy-relevance of many GHG accounting. GHG information shall be compiled,
analysed, and documented clearly and coherently so that reviewers can evaluate its credibility.
Information relating to the GHG assessment boundary, the estimation of baseline emissions shall be
sufficient to enable reviewers to understand how all conclusions were reached.
4.6 Accuracy
Uncertainties with respect to GHG measurements, estimates, or calculations shall be reduced as much as
is practical, and measurement and estimation methods shall avoid bias. Acceptable levels of uncertainty
will depend on the objectives for implementing a GHG project and the intended use of quantified GHG
reductions. Where accuracy is sacrificed, data and estimates used to quantify GHG reductions shall be
conservative.
4.7 Conservativeness
Where data and assumptions are uncertain and where the cost of measures to reduce uncertainty is not
worth the increase in accuracy, make best endeavours to use the most probable data, with an analysis
of the impact of likely uncertainty margins.
5 GHG inventory boundaries
The reporting boundaries of the GHG report for an onshore or offshore LNG liquefaction plant shall
cover all facilities which are associated with the production of LNG. Table 1 provides examples of LNG
plant facilities.
[1]
Table 1 — List of LNG plant facilities
Out of
In scope of
LNG Plant Facility scope of
the report
the report
Natural Gas Production X
Shipping / Pipeline Transport X
Inlet gas Receiving Facilities X
Condensate Unit (where applicable) X
Pre-treatment Units (e.g. acid gas remov-
al, dehydration, mercury removal, heavies X
removal, others)
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ISO 6338:2023(E)
TTabablele 1 1 ((ccoonnttiinnueuedd))
Out of
In scope of
LNG Plant Facility scope of
the report
the report
LPG Extraction and Fractionation (where
X
applicable)
Liquefaction Unit X
LNG Storage and Loading X
Flare and Disposal Systems X
Carbon Capturing Unit X
Utilities Supply (on-site power generation) X
Utilities Supply (imported) X
Plant Utilities and Infrastructure (e.g.
X
plant piping and marine facilities)
Regasification X
The organization having financial and/or operational control over the LNG liquefaction plant shall
report all GHG emissions and removals within the reporting boundaries at least on an annual average
basis.
6 Quantification of GHG emissions
6.1 Identification of GHG sources and quantification approach
6.1.1 General
The main emission sources to consider derive from fuel combustion, flaring, releases to atmosphere
(including fugitive emissions) and emissions associated with imported energy or consumables. Tables 2
to 5 give an initial checklist of emission sources to consider, and an overview of typical quantification
methods suitable for different emission sources.
The chosen method of quantification per emissions source will differ from one LNG facility to another.
Different plants will have access to a varying number of flow meters, composition analysis equipment
and level meters available.
Operators shall develop a GHG quantification plan to map out how all emission sources can best be
identified in the facility, with a preference to obtain primary data for all major emission sources. The
measurement plan shall also include an assessment of data accuracy and impact on the total GHG
emissions calculation. This assessment will then allow the operator to assess if there is a need to
further improve the amount or accuracy of instruments available for the total assessment. Guidance on
this assessment is detailed in ISO 14064-1:2018, Annex C.
A list of activity data shall be defined based on reliability as primary and secondary data:
— Primary data: quantified value of a process or an activity obtained from a direct measurement or a
calculation based on direct measurements
— Secondary data: data obtained from sources other than primary data
There is always a preference to use primary data. Only in the absence of primary data, secondary data
may be used, that could include estimated quantities and industry average emission factors.
Typically, primary data is recorded to enable GHG quantification contributing >5 % of the site’s total
GHG emissions. For smaller individual sources a calculated approach is acceptable.
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ISO 6338:2023(E)
The following subclauses describe sources to consider and typical quantification approach for the main
emissions sources.
6.1.2 Emissions from fuel combustion
The quantification approaches for emissions from fuel combustion are described in Table 2.
Table 2 — Emissions from fuel combustion at LNG liquefaction facilities
Source Examples Quantification approach
Gas turbine driv- Primary liquefaction drivers, power Typically, primary data is recorded to enable
ers generation drivers, other refrigeration GHG quantification. As a minimum, fuel gas
drivers (e.g. fractionation), CO sequestra- consumption and composition are required.
2
tion compressor drivers (Noting that fuel composition at an LNG plant
can vary widely depending on operating mode)
Diesel drivers Firewater pumps, power generation, boil- Operator may report typical annual diesel
er feed water pumps consumption and include resulting annual
emissions as a nominal allowance in the GHG
calculation
Boilers Steam for turbine drivers, steam for pro- Typically, primary data is recorded to enable
cess heating GHG quantification for major fuel consumers
(contributing >5 % of the total GHG emissions.)
As a minimum, fuel gas consumption and com-
position shall be measured
Fired heaters Regeneration gas heater, heating medium If fuel measurements are available, operator
heater, direct fired reboilers should record total fuel gas consumption and
composition. If direct fuel measurements are
not available, a calculation ba
...
ISO/FDIS 6338:20222023(E)
ISO/TC 67/SC 9/WG 10
Date: 2022-11-232023-01
Secretariat: AFNOR
Method to calculate GHG emissions at LNG plant
Méthode pour calculer les émissions de GES dans les usines GNL
---------------------- Page: 1 ----------------------
ISO/FDIS 6338:20222023(E)
© ISO 20222023
All rights reserved. Unless otherwise specified, 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
Ch. de Blandonnet 8 • CP 401
CH-1214 Vernier, Geneva, Switzerland
Tel. + 41 22 749 01 11
Fax + 41 22 749 09 47
copyright@iso.org
www.iso.org
ii © ISO 20222023 – All rights reserved
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ISO/FDIS 6338:20222023(E)
Contents
Foreword . 5
Introduction . 6
1 Scope . 7
2 Normative references . 8
3 Terms and definitions . 8
4 Principles . 10
4.1 General . 10
4.2 Relevance . 10
4.3 Completeness . 10
4.4 Consistency . 10
4.5 Transparency . 10
4.6 Accuracy . 11
4.7 Conservativeness . 11
5 GHG inventory boundaries . 11
[1]
Table 1 — List of LNG plant facilities . 11
6 Quantification of GHG emissions . 12
6.1 Identification of GHG sources and quantification approach . 12
6.1.1 General . 12
6.1.2 Emissions from fuel combustion . 12
Table 2 — Emissions from fuel combustion at LNG liquefaction facilities . 12
6.1.3 Emissions from flaring and venting . 13
Table 3 — Emissions from flaring and venting at LNG liquefaction facilities . 13
6.1.4 Fugitive emissions . 13
Table 4 — Fugitive emissions at LNG liquefaction facilities . 13
6.1.5 Emissions associated with imported energy, utilities, and consumables . 14
Table 5 — Emissions associated with imported energy, utilities, and consumables 14
6.2 Calculation of GHG emissions . 14
6.2.1 Requirements and guidance . 14
6.2.2 GHG inventory . 15
6.2.3 GHG quantification methods for fuel combustion . 17
6.2.4 GHG quantification methods for flaring and venting . 18
6.2.5 GHG Quantification methods for fugitive emissions . 18
6.2.6 Quantification methods for emissions from imported energy, utilities, and
consumables . 19
6.2.7 Relevant period and frequency . 20
6.3 Preferred units . 20
6.4 Allocation . 20
6.4.1 Principles . 20
6.4.2 Methodology . 20
6.5 Carbon capture . 25
6.5.1 Opportunities for carbon capture: . 25
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ISO/FDIS 6338:20222023(E)
6.5.2 Quantification of carbon capture benefit . 25
7 GHG inventory quality management . 25
7.1 General . 25
7.2 GHG Emission Calculation approach . 26
7.3 Estimation of inventory uncertainties . 26
7.4 Procedures for documentation and archiving . 26
7.5 Quality Control . 26
7.6 Quality Assurance . 27
8 GHG reporting . 28
8.1 General . 28
8.2 Additional information . 28
8.3 GHG emission reduction . 29
8.4 Carbon offset and emission trading. 29
9 Independent review . 29
Annex A (informative) Conversion factors for reference . 30
A.1 Unit conversion factors . 30
Table A.1 — Unit conversion factors . 30
A.2 Approximate conversions . 30
Table A.2 — Approximate conversions (dependant on specific LNG product
properties) . 30
Annex B (informative) International initiatives on climate ambitions . 31
Table B.1 —KPIs and related requirements . 31
Annex C (informative) Example allocation calculation . 34
Figure C.1 — LNG plant example . 35
Figure C.2 — Minimum block flow diagram . 35
Table C.1 — Total annual emissions in example . 36
Table C.2 — Total annual emissions from fuel use in example . 36
Table C.3 — Identifying the breakdown of benefits from the gas turbines . 40
Figure C.3 — Completed allocation calculation . 44
Table C.4 — Results . 45
Bibliography . 47
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ISO/FDIS 6338:20222023(E)
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 documents 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).
Attention is drawn to the possibility that some of the elements of this document may be the
subject of patent rights. ISO shall not be held responsible for identifying any or all such patent
rights. Details of any patent rights identified during the development of the document will be in
the Introduction and/or on the ISO list of patent declarations received (see
www.iso.org/patents).
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 67, Oil and gas industries including
lower carbon energy, Subcommittee SC 9, Production, transport and storage facilities for cryogenic
liquefied gases.
A list of all parts in the ISO 6338 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.
© ISO 20222023 – All rights reserved v
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ISO/FDIS 6338:20222023(E)
Introduction
Natural gas will play a key role in the energy transition (e.g. by replacing coal to produce
electricity) and the use of LNG to transport natural gas is expected to increase. The process of
liquefying natural gas is energy-intensive. Gas producers are increasingly accountable for their
greenhouse gas (GHG) emissions and the ambition to reduce them. Furthermore, there is an
emerging marketing demand for GHG data to enable commercial mechanisms such as offsetting
to be utilisedutilized.
There is no standardisedstandardized and auditable methodology to calculate the carbon
footprint of the whole LNG chain (including but not limited to the well, upstream treatment,
transportation, liquefaction, shipping, regasification and end user distribution). Various
standards indicate possible approaches but these are not consistent in their results or easily
applicable.
The intention is to develop documents for each part of the LNG chain and to start with
liquefaction. Attention should be paid to activities that can occur in different parts (e.g. gas
treatment and distribution upstream of the liquefaction plant).
NOTE It will not be possible to make like-for-like comparisons, or define a certification scheme, for one
block only.
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ISO/FDIS 6338:2022(E)
Method to calculate GHG emissions at LNG plant
1 Scope
This document provides a method to calculate the GHG emissions from an LNG liquefaction plant,
onshore or offshore.
The frame of this document ranges from the inlet flange of the LNG plant’s inlet facilities up to
and including the offloading arms to truck, ship or railcar loading. The upstream supply of gas up
to the inlet flange of the inlet facilities and the distribution of LNG downstream of the loading
arms are only covered in general terms.
This document covers:
- — all facilities associated with producing LNG, including reception facilities, condensate unit
(where applicable), pre-treatment units (including but not limited to acid gas removal,
dehydration, mercury removal, heavies removal), LPG extraction and fractionation (where
applicable), liquefaction, LNG storage and loading, Boil-Off-Gas handling, flare and disposal
systems, imported electricity or on-site power generation and other plant utilities and
infrastructure (e.g. marine and transportation facilities).
- — natural gas liquefaction facilities associated with producing other products (e.g. domestic gas,
condensate, LPG, sulphur, power export) to the extent required to allocate GHG emissions to
the different products.
- — all GHG emissions associated with producing LNG. These emissions spread across scope 1,
scope 2 and scope 3 of the responsible organization. Scope 1, 2 and 3 are defined in this
document. All emissions sources are covered including flaring, combustion, cold vents,
process vents, fugitive leaks and emissions associated with imported energy.
The LNG plant is considered “under operation”, including emissions associated with initial start-
up, maintenance, turnaround and restarts after maintenance or upset. The construction,
commissioning, extension and decommissioning phases are excluded from this document but
maycan be assessed separately.
The emissions resulting from boil-off gas management during loading of the ship or any export
vehicle are covered by this document. The emissions from a ship at berth, e.g. mast venting are
not covered by this document.
This document describes the allocation of GHG emissions to LNG and other hydrocarbon products
where other products are produced (e.g. LPG, domestic gas, condensates, sulphur…)., etc.).
This document defines preferred units of measurement and necessary conversions.
This document also recommends instrumentation and estimations methods to monitor and
report GHG emissions. Some emissions are measured, and some are estimated.
This document is applicable to the LNG industry.
Applications include the provision of method to calculate GHG emissions through a
standardisedstandardized and auditable method, a means to determine their carbon footprint.
© ISO 2022 – All rights reserved 7
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ISO/FDIS 6338:2022(E)
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 14044, Environmental management — Life cycle assessment — Requirements and guidelines
ISO 14064-1, Greenhouse gases — Part 1: Specification with guidance at the organization level for
quantification and reporting of greenhouse gas emissions and removals
API Consistent Methodology for Estimating Greenhouse Gas Emissions from Liquefied Natural Gas
(LNG) Operations
3 Terms and definitions
For the purposes of this document, the terms and definitions fromgiven in ISO 14064-1 apply. In
addition, and 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
facility
single installation, set of installations or production processes (stationary or mobile), which can
be defined within a single geographical boundary, organizational unit or production process
[SOURCE: ISO 14064-1:2018, 3.4.1]
3.2
global warming potential
GWP
ratio of the time-integrated radiative forcing (warming effect) from the instantaneous release of
1 kg of the GHG relative to that from the release of 1 kg of CO2
3.3
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 GHGs, see the 6th Intergovernmental Panel on Climate Change (IPCC)
Assessment Report.
Note 2 to entry: Water vapour and ozone are anthropogenic as well as natural GHGs, but are not included
as recognized GHGs due to difficulties, in most cases, in isolating the human-induced component of global
warming attributable to their presence in the atmosphere.
8 © ISO 2022 – All rights reserved
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ISO/FDIS 6338:2022(E)
[SOURCE: ISO 14064-1:2018, 3.1.1]
3.4
organizational boundary
grouping of activities or facilities in which an organization exercises operational or financial
control or has an equity share
[SOURCE: ISO 14064-1:2018, 3.4.7]
3.5
reporting boundary
grouping of greenhouse gas (GHG) emission or GHG removals reported from within the
organizational boundary, as well as those significant indirect emissions that are a consequence of
the organization’s operations and activities
[SOURCE: ISO 14064-1:2018, 3.4.8]
3.6
scope 1
direct greenhouse gas emissions
direct GHG emissions
scope 1
emissions coming from sources that are owned or controlled by the facility
Note 1 to entry: This can be the emissions that are directly created by product fabrication or synthesis, for
example, combustion fumes from a refinery.
3.7
scope 2
indirect greenhouse gas emissions from purchased and consumed energy
indirect GHG emissions from purchased and consumed energy
scope 2
emissions from the generation of imported electricity, steam, and heating/cooling consumed by
the facillity
Note 1 to entry: These emissions physically occur at the facility where electricity, steam and cooling or
heating are generated but as a user of the energy, the consuming party is still responsible for the
greenhouse gas emissions that are being created.
3.8
scope 3
other indirect greenhouse gas emissions
other indirect GHG emissions
scope 3
emissions from sources that are not owned and not directly controlled by the facility
Note 1 to entry: However, they are related to the company’s activities. This is usually considered to be the
supply chain of the company, so emissions caused by vendors within the supply chain, outsourced activities,
and employee travel and commute. In many industries, other indirect GHG emissions account for the
biggest amount of GHG emissions. This is due to the fact that in today’s economy, many tasks are outsourced
and few companies own the entire value chain of their products.
3.9
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ISO/FDIS 6338:2022(E)
quality assurance
QA
planned system of review procedures conducted by personnel not directly involved in the
inventory compilation/development process
3.10
quality control
QC
planned system of review procedures conducted by personnel not directly involved in the
inventory compilation/development process
4 Principles
4.1 General
The application of the following principles is fundamental to guarantee that GHG calculations are
a true and fair account.
4.2 Relevance
Use data, methods, criteria, and assumptions that are appropriate for the intended use of reported
information. The quantification and reporting of GHG emissions shall include only information
that users— — both internal and external to the plant — need for their decision-making. This
information shall thus fit the intended purpose of the GHG project and meet the expectations or
requirements of its users. Data, methods, criteria, and assumptions that are misleading or that do
not conform to this document are not relevant and shall not be included.
4.3 Completeness
Consider all relevant information that mightcan affect the accounting and quantification of GHG
reductions, and complete all requirements. All relevant information shall be included in the
quantification of GHG emissions. A GHG monitoring plan shall also specify how all data relevant
to quantifying GHG reductions will be collected.
4.4 Consistency
Use data, methods, criteria, and assumptions that allow meaningful and valid comparisons. The
credible quantification of GHG emissions requires that methods and procedures are always in the
same manner, that the same criteria and assumptions are used to evaluate significance and
relevance, and that any data collected and reported will be compatible enough to allow
meaningful comparisons over time.
4.5 Transparency
Provide clear and sufficient information for reviewers to assess the credibility and reliability of
GHG emissions claims. Transparency is critical for quantifying and reporting GHG reductions,
particularly given the flexibility and policy-relevance of many GHG accounting. GHG information
shall be compiled, analysed, and documented clearly and coherently so that reviewers mightcan
evaluate its credibility. Information relating to the GHG assessment boundary, the estimation of
baseline emissions shall be sufficient to enable reviewers to understand how all conclusions were
reached.
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ISO/FDIS 6338:2022(E)
4.6 Accuracy
Uncertainties with respect to GHG measurements, estimates, or calculations shall be reduced as
much as is practical, and measurement and estimation methods shall avoid bias. Acceptable levels
of uncertainty will depend on the objectives for implementing a GHG project and the intended use
of quantified GHG reductions. Where accuracy is sacrificed, data and estimates used to quantify
GHG reductions shall be conservative.
4.7 Conservativeness
Where data and assumptions are uncertain and where the cost of measures to reduce uncertainty
is not worth the increase in accuracy, make best endeavours to use the most probable data, with
an analysis of the impact of likely uncertainty margins.
5 GHG inventory boundaries
The reporting boundaries of the GHG report for an onshore or offshore LNG liquefaction plant
shall cover all facilities which are associated with the production of LNG. Table 1 provides
examples of LNG plant facilities.
[1]
Table 1 — List of LNG plant facilities
Out of
In scope of
LNG Plant Facility scope of
the report
the report
Natural Gas Production X
Shipping / Pipeline Transport X
Inlet gas Receiving Facilities X
Condensate Unit (where applicable) X
Pre-treatment Units (e.g. acid gas removal,
dehydration, mercury removal, heavies X
removal, others)
LPG Extraction and Fractionation (where
X
applicable)
Liquefaction Unit X
LNG Storage and Loading X
Flare and Disposal Systems X
Carbon Capturing Unit X
Utilities Supply (on-site power
X
generation)
Utilities Supply (imported) X
Plant Utilities and Infrastructure (e.g.
X
plant piping and marine facilities)
Regasification X
The organization having financial and/or operational control over the LNG liquefaction plant
shall report all GHG emissions and removals within the reporting boundaries at least on an annual
average basis.
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ISO/FDIS 6338:2022(E)
6 Quantification of GHG emissions
6.1 Identification of GHG sources and quantification approach
6.1.1 General
The main emission sources to consider derive from fuel combustion, flaring, releases to
atmosphere (including fugitive emissions) and emissions associated with imported energy or
consumables. Tables 2 to 5 give an initial checklist of emission sources to consider, and an
overview of typical quantification methods suitable for different emission sources.
The chosen method of quantification per emissions source will differ from one LNG facility to
another. Different plants will have access to a varying number of flow meters, composition
analysis equipment and level meters available.
Operators shall develop a GHG quantification plan to map out how all emission sources can best
be identified in the facility, with a preference to obtain primary data for all major emission
sources. The measurement plan shall also include an assessment of data accuracy and impact on
the total GHG emissions calculation. This assessment will then allow the operator to assess if
there is a need to further improve the amount or accuracy of instruments available for the total
assessment. Guidance on this assessment is detailed in ISO 14064-1:2018, Annex C.
A list of activity data shall be defined based on reliability as primary and secondary data:
— Primary data: quantified value of a process or an activity obtained from a direct measurement
or a calculation based on direct measurements
— Secondary data: data obtained from sources other than primary data
There is always a preference to use primary data. Only in the absence of primary data, secondary
data may be used, that could include estimated quantities and industry average emission factors.
Typically, primary data is recorded to enable GHG quantification contributing >5 % of the site’s
total GHG emissions. For smaller individual sources a calculated approach is acceptable.
The following subclauses describe sources to consider and typical quantification approach for the
main emissions sources.
6.1.2 Emissions from fuel combustion
The quantification approaches for emissions from fuel combustion are described in Table 2.
Table 2 — Emissions from fuel combustion at LNG liquefaction facilities
Source Examples Quantification approach
Gas turbine Primary liquefaction drivers, power Typically, primary data is recorded to enable
drivers generation drivers, other refrigeration GHG quantification. As a minimum, fuel gas
drivers (e.g. fractionation), CO2 consumption and composition are required.
sequestration compressor drivers (Noting that fuel composition at an LNG plant
can vary widely depending on operating mode)
Diesel drivers Firewater pumps, power generation, Operator may report typical annual diesel
boiler feed water pumps consumption and include resulting annual
emissions as a nominal allowance in the GHG
calculation
Boilers Steam for turbine drivers, steam for Typically, primary data is recorded to enable
process heating GHG quantification for major fuel consumers
12 © ISO 2022 – All rights reserved
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ISO/FDIS 6338:2022(E)
Source Examples Quantification approach
(contributing >5 % of the total GHG emissions.)
As a minimum, fuel gas consumption and
composition shall be measured
Fired heaters Regeneration gas heater, heating medium If fuel measurements are available, operator
heater, direct fired reboilers should record total fuel gas consumption and
composition. If direct fuel measurements are
not available, a calculation based on operating
duty and effici
...
FINAL
INTERNATIONAL ISO/FDIS
DRAFT
STANDARD 6338
ISO/TC 67/SC 9
Method to calculate GHG emissions at
Secretariat: AFNOR
LNG plant
Voting begins on:
2023-03-02
Méthode pour calculer les émissions de GES dans les usines GNL
Voting terminates on:
2023-04-27
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
Reference number
BEING ACCEPTABLE FOR INDUSTRIAL, TECHNO-
ISO/FDIS 6338:2023(E)
LOGICAL, COMMERCIAL AND USER PURPOSES,
DRAFT INTERNATIONAL STANDARDS MAY ON
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LIGHT OF THEIR POTENTIAL TO BECOME STAN-
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NATIONAL REGULATIONS. © ISO 2023
---------------------- Page: 1 ----------------------
ISO/FDIS 6338:2023(E)
FINAL
INTERNATIONAL ISO/FDIS
DRAFT
STANDARD 6338
ISO/TC 67/SC 9
Method to calculate GHG emissions at
Secretariat: AFNOR
LNG plant
Voting begins on:
Méthode pour calculer les émissions de GES dans les usines GNL
Voting terminates on:
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or ISO’s member body in the country of the requester.
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ii
© ISO 2023 – All rights reserved
NATIONAL REGULATIONS. © ISO 2023
---------------------- Page: 2 ----------------------
ISO/FDIS 6338:2023(E)
Contents Page
Foreword .v
Introduction . vi
1 Scope . 1
2 Normative references . 1
3 Terms and definitions . 2
4 Principles . 3
4.1 General . 3
4.2 Relevance . 3
4.3 Completeness . 4
4.4 Consistency . 4
4.5 Transparency . 4
4.6 Accuracy . 4
4.7 Conservativeness. 4
5 GHG inventory boundaries .4
6 Quantification of GHG emissions . 5
6.1 Identification of GHG sources and quantification approach . 5
6.1.1 General . 5
6.1.2 Emissions from fuel combustion . . 6
6.1.3 Emissions from flaring and venting . 6
6.1.4 Fugitive emissions . 7
6.1.5 Emissions associated with imported energy, utilities, and consumables . 7
6.2 Calculation of GHG emissions . 8
6.2.1 Requirements and guidance . 8
6.2.2 GHG inventory . . 8
6.2.3 GHG quantification methods for fuel combustion . 10
6.2.4 GHG quantification methods for flaring and venting . 10
6.2.5 GHG Quantification methods for fugitive emissions . 11
6.2.6 Quantification methods for emissions from imported energy, utilities, and
consumables . 12
6.2.7 Relevant period and frequency .12
6.3 Preferred units .12
6.4 Allocation . 13
6.4.1 Principles .13
6.4.2 Methodology . . 13
6.5 Carbon capture . 16
6.5.1 Opportunities for carbon capture: . 16
6.5.2 Quantification of carbon capture benefit . 16
7 GHG inventory quality management .16
7.1 General . 16
7.2 GHG Emission Calculation approach . 17
7.3 Estimation of inventory uncertainties . 17
7.4 Procedures for documentation and archiving . 17
7.5 Quality Control . 17
7.6 Quality Assurance . 18
8 GHG reporting .19
8.1 General . 19
8.2 Additional information. 19
8.3 GHG emission reduction . 19
8.4 Carbon offset and emission trading . 20
9 Independent review . .20
iii
© ISO 2023 – All rights reserved
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ISO/FDIS 6338:2023(E)
Annex A (informative) Conversion factors for reference .21
Annex B (informative) International initiatives on climate ambitions .22
Annex C (informative) Example allocation calculation .24
Bibliography .30
iv
© ISO 2023 – All rights reserved
---------------------- Page: 4 ----------------------
ISO/FDIS 6338:2023(E)
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 nongovernmental, 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 documents 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).
Attention is drawn to the possibility that some of the elements of this document may be the subject of
patent rights. ISO shall not be held responsible for identifying any or all such patent rights. Details of
any patent rights identified during the development of the document will be in the Introduction and/or
on the ISO list of patent declarations received (see www.iso.org/patents).
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 67, Oil and gas industries including lower
carbon energy, Subcommittee SC 9, Production, transport and storage facilities for cryogenic liquefied
gases.
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.
v
© ISO 2023 – All rights reserved
---------------------- Page: 5 ----------------------
ISO/FDIS 6338:2023(E)
Introduction
Natural gas will play a key role in the energy transition (e.g. by replacing coal to produce electricity)
and the use of LNG to transport natural gas is expected to increase. The process of liquefying natural
gas is energy-intensive. Gas producers are increasingly accountable for their greenhouse gas (GHG)
emissions and the ambition to reduce them. Furthermore, there is an emerging marketing demand for
GHG data to enable commercial mechanisms such as offsetting to be utilized.
There is no standardized and auditable methodology to calculate the carbon footprint of the whole LNG
chain (including but not limited to the well, upstream treatment, transportation, liquefaction, shipping,
regasification and end user distribution). Various standards indicate possible approaches but these are
not consistent in their results or easily applicable.
vi
© ISO 2023 – All rights reserved
---------------------- Page: 6 ----------------------
FINAL DRAFT INTERNATIONAL STANDARD ISO/FDIS 6338:2023(E)
Method to calculate GHG emissions at LNG plant
1 Scope
This document provides a method to calculate the GHG emissions from an LNG liquefaction plant,
onshore or offshore.
The frame of this document ranges from the inlet flange of the LNG plant’s inlet facilities up to and
including the offloading arms to truck, ship or railcar loading. The upstream supply of gas up to the
inlet flange of the inlet facilities and the distribution of LNG downstream of the loading arms are only
covered in general terms.
This document covers:
— all facilities associated with producing LNG, including reception facilities, condensate unit (where
applicable), pre-treatment units (including but not limited to acid gas removal, dehydration, mercury
removal, heavies removal), LPG extraction and fractionation (where applicable), liquefaction, LNG
storage and loading, Boil-Off-Gas handling, flare and disposal systems, imported electricity or on-
site power generation and other plant utilities and infrastructure (e.g. marine and transportation
facilities).
— natural gas liquefaction facilities associated with producing other products (e.g. domestic gas,
condensate, LPG, sulphur, power export) to the extent required to allocate GHG emissions to the
different products.
— all GHG emissions associated with producing LNG. These emissions spread across scope 1, scope
2 and scope 3 of the responsible organization. Scope 1, 2 and 3 are defined in this document. All
emissions sources are covered including flaring, combustion, cold vents, process vents, fugitive
leaks and emissions associated with imported energy.
The LNG plant is considered “under operation”, including emissions associated with initial startup,
maintenance, turnaround and restarts after maintenance or upset. The construction, commissioning,
extension and decommissioning phases are excluded from this document but can be assessed separately.
The emissions resulting from boil-off gas management during loading of the ship or any export vehicle
are covered by this document. The emissions from a ship at berth, e.g. mast venting are not covered by
this document.
This document describes the allocation of GHG emissions to LNG and other hydrocarbon products
where other products are produced (e.g. LPG, domestic gas, condensates, sulphur, etc.).
This document defines preferred units of measurement and necessary conversions.
This document also recommends instrumentation and estimations methods to monitor and report GHG
emissions. Some emissions are measured and some are estimated.
This document is applicable to the LNG industry.
Applications include the provision of method to calculate GHG emissions through a standardized and
auditable method, a means to determine their carbon footprint.
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.
1
© ISO 2023 – All rights reserved
---------------------- Page: 7 ----------------------
ISO/FDIS 6338:2023(E)
ISO 14044, Environmental management — Life cycle assessment — Requirements and guidelines
ISO 140641, Greenhouse gases — Part 1: Specification with guidance at the organization level for
quantification and reporting of greenhouse gas emissions and removals
API Consistent Methodology for Estimating Greenhouse Gas Emissions from Liquefied Natural Gas (LNG)
Operations
3 Terms and definitions
For the purposes of this document, the terms and definitions given in ISO 14064-1 and the following
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
facility
single installation, set of installations or production processes (stationary or mobile), which can be
defined within a single geographical boundary, organizational unit or production process
[SOURCE: ISO 140641:2018, 3.4.1]
3.2
global warming potential
GWP
ratio of the timeintegrated radiative forcing (warming effect) from the instantaneous release of 1 kg of
the GHG relative to that from the release of 1 kg of CO2
3.3
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 GHGs, see the 6th Intergovernmental Panel on Climate Change (IPCC) Assessment
Report.
Note 2 to entry: Water vapour and ozone are anthropogenic as well as natural GHGs, but are not included as
recognized GHGs due to difficulties, in most cases, in isolating the human-induced component of global warming
attributable to their presence in the atmosphere.
[SOURCE: ISO 140641:2018, 3.1.1]
3.4
organizational boundary
grouping of activities or facilities in which an organization exercises operational or financial control or
has an equity share
[SOURCE: ISO 140641:2018, 3.4.7]
3.5
reporting boundary
grouping of greenhouse gas (GHG) emission or GHG removals reported from within the organizational
boundary, as well as those significant indirect emissions that are a consequence of the organization’s
operations and activities
[SOURCE: ISO 140641:2018, 3.4.8]
2
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ISO/FDIS 6338:2023(E)
3.6
scope 1
direct greenhouse gas emissions
direct GHG emissions
emissions coming from sources that are owned or controlled by the facility
Note 1 to entry: This can be the emissions that are directly created by product fabrication or synthesis, for
example, combustion fumes from a refinery.
3.7
scope 2
indirect greenhouse gas emissions from purchased and consumed energy
indirect GHG emissions from purchased and consumed energy
emissions from the generation of imported electricity, steam, and heating/cooling consumed by the
facillity
Note 1 to entry: These emissions physically occur at the facility where electricity, steam and cooling or heating
are generated but as a user of the energy, the consuming party is still responsible for the greenhouse gas
emissions that are being created.
3.8
scope 3
other indirect greenhouse gas emissions
other indirect GHG emissions
emissions from sources that are not owned and not directly controlled by the facility
Note 1 to entry: However, they are related to the company’s activities. This is usually considered to be the
supply chain of the company, so emissions caused by vendors within the supply chain, outsourced activities, and
employee travel and commute. In many industries, other indirect GHG emissions account for the biggest amount
of GHG emissions. This is due to the fact that in today’s economy, many tasks are outsourced and few companies
own the entire value chain of their products.
3.9
quality assurance
QA
planned system of review procedures conducted by personnel not directly involved in the inventory
compilation/development process
3.10
quality control
QC
planned system of review procedures conducted by personnel not directly involved in the inventory
compilation/development process
4 Principles
4.1 General
The application of the following principles is fundamental to guarantee that GHG calculations are a true
and fair account.
4.2 Relevance
Use data, methods, criteria, and assumptions that are appropriate for the intended use of reported
information. The quantification and reporting of GHG emissions shall include only information that
users — both internal and external to the plant — need for their decision-making. This information
shall thus fit the intended purpose of the GHG project and meet the expectations or requirements of
its users. Data, methods, criteria, and assumptions that are misleading or that do not conform to this
document are not relevant and shall not be included.
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4.3 Completeness
Consider all relevant information that can affect the accounting and quantification of GHG reductions,
and complete all requirements. All relevant information shall be included in the quantification of GHG
emissions. A GHG monitoring plan shall also specify how all data relevant to quantifying GHG reductions
will be collected.
4.4 Consistency
Use data, methods, criteria, and assumptions that allow meaningful and valid comparisons. The credible
quantification of GHG emissions requires that methods and procedures are always in the same manner,
that the same criteria and assumptions are used to evaluate significance and relevance, and that any
data collected and reported will be compatible enough to allow meaningful comparisons over time.
4.5 Transparency
Provide clear and sufficient information for reviewers to assess the credibility and reliability of GHG
emissions claims. Transparency is critical for quantifying and reporting GHG reductions, particularly
given the flexibility and policy-relevance of many GHG accounting. GHG information shall be compiled,
analysed, and documented clearly and coherently so that reviewers can evaluate its credibility.
Information relating to the GHG assessment boundary, the estimation of baseline emissions shall be
sufficient to enable reviewers to understand how all conclusions were reached.
4.6 Accuracy
Uncertainties with respect to GHG measurements, estimates, or calculations shall be reduced as much as
is practical, and measurement and estimation methods shall avoid bias. Acceptable levels of uncertainty
will depend on the objectives for implementing a GHG project and the intended use of quantified GHG
reductions. Where accuracy is sacrificed, data and estimates used to quantify GHG reductions shall be
conservative.
4.7 Conservativeness
Where data and assumptions are uncertain and where the cost of measures to reduce uncertainty is not
worth the increase in accuracy, make best endeavours to use the most probable data, with an analysis
of the impact of likely uncertainty margins.
5 GHG inventory boundaries
The reporting boundaries of the GHG report for an onshore or offshore LNG liquefaction plant shall
cover all facilities which are associated with the production of LNG. Table 1 provides examples of LNG
plant facilities.
[1]
Table 1 — List of LNG plant facilities
Out of
In scope of
LNG Plant Facility scope of
the report
the report
Natural Gas Production X
Shipping / Pipeline Transport X
Inlet gas Receiving Facilities X
Condensate Unit (where applicable) X
Pretreatment Units (e.g. acid gas remov
al, dehydration, mercury removal, heavies X
removal, others)
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TTabablele 1 1 ((ccoonnttiinnueuedd))
Out of
In scope of
LNG Plant Facility scope of
the report
the report
Natural Gas Production X
LPG Extraction and Fractionation (where
X
applicable)
Liquefaction Unit X
LNG Storage and Loading X
Flare and Disposal Systems X
Carbon Capturing Unit X
Utilities Supply (on-site power generation) X
Utilities Supply (imported) X
Plant Utilities and Infrastructure (e.g.
X
plant piping and marine facilities)
Regasification X
The organization having financial and/or operational control over the LNG liquefaction plant shall
report all GHG emissions and removals within the reporting boundaries at least on an annual average
basis.
6 Quantification of GHG emissions
6.1 Identification of GHG sources and quantification approach
6.1.1 General
The main emission sources to consider derive from fuel combustion, flaring, releases to atmosphere
(including fugitive emissions) and emissions associated with imported energy or consumables. Tables 2
to 5 give an initial checklist of emission sources to consider, and an overview of typical quantification
methods suitable for different emission sources.
The chosen method of quantification per emissions source will differ from one LNG facility to another.
Different plants will have access to a varying number of flow meters, composition analysis equipment
and level meters available.
Operators shall develop a GHG quantification plan to map out how all emission sources can best be
identified in the facility, with a preference to obtain primary data for all major emission sources. The
measurement plan shall also include an assessment of data accuracy and impact on the total GHG
emissions calculation. This assessment will then allow the operator to assess if there is a need to
further improve the amount or accuracy of instruments available for the total assessment. Guidance on
this assessment is detailed in ISO 14064-1:2018, Annex C.
A list of activity data shall be defined based on reliability as primary and secondary data:
— Primary data: quantified value of a process or an activity obtained from a direct measurement or a
calculation based on direct measurements
— Secondary data: data obtained from sources other than primary data
There is always a preference to use primary data. Only in the absence of primary data, secondary data
may be used, that could include estimated quantities and industry average emission factors.
Typically, primary data is recorded to enable GHG quantification contributing >5 % of the site’s total
GHG emissions. For smaller individual sources a calculated approach is acceptable.
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The following subclauses describe sources to consider and
...
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