Recommended guidelinefor
Greenhouse gas and Carbon intensity accounting
framework for LNG/Hydrogen/Ammonia project(JOGMEC GHG/CI guideline)
Executive Summary
Version 1
Published May 2022
Japan Oil, Gas and Metals National Corporation(JOGMEC)

Preface, background, and purpose
JOGMEC hereby presents a guideline (hereinafter “Guideline”) to enable the calculation of greenhouse gasemissions (GHG) and carbon intensity (CI) according to the actual operation mode by comparing and examining
several international standards related to GHG emissions. This is one of JOGMEC’s actions to support theimplementation of liquified natural gas (LNG), ammonia, and hydrogen projects by Japanese business entities.
Important to note is that this guideline has been established according to current international standards and does
NOT propose a new methodology. The content of this Guideline includes 1) appropriately setting the systemboundaries to enhance the transparency and comparability with other guidelines, 2) recommends using primary data(measurement, operation data, equipment-specific emission factor) for major GHG emission sources to calculate theGHG emission that reflects the actual operation mode, and 3) provides a transparent GHG emissions approach toreflect the environmental value of the product / energy source.
＜Steps for calculating CI＞⚫

Step 1: Identify the process and flow for each stage of the product lifecycle⚫

Step 2: Prepare data to calculate GHG emissions and CI for each identified process/flow⚫

Step 3: Identify byproducts and determine the GHG allocation method⚫

Step 4: Determine the GHG emission calculation method for the product⚫

Step 5: Calculate the carbon footprint (CFP) of the product⚫

Step 6: Calculate the CI of the product, and compile in report⚫

Step 7: Report the CI (if necessary, after third-party verification)

Chapter 1
Coverage of Guideline and data handlingThis chapter outlines the boundaries of the Guideline for calculating the GHG emissions of the targeted products(LNG, hydrogen, and ammonia). As previously noted, the guideline is not meant to propose a new methodology;
however, it does define the system boundaries and central premise behind the system flow, and method for reportingthe calculation results.
1.

System boundaries

Basic philosophy
This guideline sets the boundary from the feedstock production until the export point of the final product (Well toGate). GHG emissions related to the process after the export point (e.g., storage, transportation, supply, and finalconsumption) are not considered.

1Fig 1:System boundaries and process
The amount of energy input, waste, and atmospheric emissions should be identified for each process. If there isdoubt when comparing the input and output data, additional data may be necessary to verify the fairness. The collected
data included the following:⚫

Energy input, and other input (if any)⚫

All byproducts⚫

Waste products, direct atmospheric emission

Cut-off criteria
The cut-off criteria refer to the material/energy flow and GHG emissions not included in the CFP calculation. Theguideline recommends not using cut-off criteria and suggests the use of alternate data to calculate GHG emissions.
Simultaneously, it refers to the England carbon footprint standard (PAS2050) if a cutoff needs to be set.
Allocation
If several products are produced during the process of each boundary, GHG emissions must be allocated between
the main product and byproduct. The guideline refers to the ISO14044 to break down the process or expand thesystem boundary as a means to avoid allocation.
2.

Calculation data

Data aggregation and quality
For each process inside the boundary, input data (energy input and consumption) and output data (waste products
and atmospheric emissions) needs to be collected. High-quality data will help ensure assure the accuracy of GHG
emissions and reduce uncertainty and bias. Where applicable, using primary data is recommended to ensure highquality data.

2Chapter 2
GHG emission calculation
This chapter explains the GHG emission calculation method for the targeted products.
１. GHG of interest
The Guideline focuses on the following as “GHG”⚫

Carbon dioxide（CO2）⚫

Methane（CH4）⚫

Nitrous oxide（N2O）⚫

Hydrofluorocarbons（HFC）⚫

Perfluorocarbons（PFC）⚫

Sulfur hexafluoride（SF6）⚫

Nitrogen trifluoride（NF3）

２. GHG emission source
GHG emission categories and the main source of emission are listed in Table 1.
Table 1: Main emission sources for each emission category
Priority for data gathering
Primary data (direct)

Direct measurement, flow measurement, and gas
sampling

Primary data (indirect)

Engineering assumption and fuel composition
modelled under a process-specific condition.

Secondary data (direct)

De-facto value according to the process. Includes
values that are derived from LCA models, wherespecific primary data is used as an input.

Secondary data (indirect)

Standardized emission factors, values that arederived from LCA models, where specific primarydata is NOT used as an input.

33. Calculation of GHG emission
Typical GHG calculation methods include the following:

Categorization

Primary data

Table 2: GHG calculation methodology and its features
Calculation
Carbon dioxideMethane（CH4）methodology(CO2)
Nitrous Oxide（N２O）
CO2 emission relies on
the fuel type rather thanspecific equipment
Emission relies
Project specific
Emission factors
heavily on specificemission factor
provided byequipment
manufacture is based on
combustion equipment,
fuel, air-fuel ratioCan be applied tovarious emission
Engineering calculation
sources, but relies on the 
May need specificwith operation data
methodology anddata
assumptions
May need specific data
Emission factor derived
from activity factorAccuracy is comparable 
Emission factor that(actual measurement
to that of thereflects the actual
data and/or operationengineering calculation
operation modedata)Accuracy is comparable
to that of engineering
calculation

Based on averagecarbon content of each
fuel
Fuel composition isderived from fuel type

Direct measurement

Secondary data

Conventional emission
factorHigh accuracy
Requires intense
cost and timeEmission relies
heavily on specificequipment
Uncertainty does nothave much effect on
the overall emission

Source: API, 2021: Compendium of Greenhouse Gas Emissions Methodologies for the Oil and Natural Gas Industry, USA, 138 pp. (Table 4-1), partiallyamendedTo calculate GHG emissions, many guidelines adopt the secondary data method by multiplying the general emission
factor and the activity factor rather than using direct measurement data. However, this method may not accuratelyreflect the actual operation mode of a plant. Thus, the Guideline recommends using primary data, especially for major
emission sources. The GHG emissions amount can be calculated using the following equation for both direct andindirect emissions:
GHG emission[t-CO2eq]＝Activity factor×GHG emission factor×coefficient×GWP⚫

Activity factor: Activity data for a certain period. Primary data are recommended, although the assumed value
may be used.
4⚫

GHG emission factor: GHG emission data per unit of activity unit. The emission factor should be determinedbased on the direct measurement data (gas sampling) or a value specific to the target fuel or equipment.

⚫

Coefficient: Additional factors for GHG emission calculation, such as unit conversion, emission factor
adjustment, and heating value adjustment.

⚫

GWP (Global Warming Potential): GWPs for major GHG are described in Chapter 2 (1).

3.

Methane leakage

Methane is known to contribute to climate change and there are global movements for the reduction of methaneemissions. LNG or methane-derived hydrogen and ammonia projects have usually introduced measurements toreduce fugitive methane; however, there are cases where methane is released into the atmosphere. Thus, anappropriate management system is increasingly important to ensure that methane leakage is not excluded from theGHG emission calculation. Methane measurement methods can be categorized as “bottom-up” and “top-down”,
which will be discussed in this section.

Fig 3: Illustration of methane measurement
4.

Production process flow

This section describes the typical block flow used to produce LNG, hydrogen, and ammonia. The process and flow
should be adjusted according to the target plant when applying the Guideline.
5.

Selection of GHG emission calculation methodology

The Guideline recommends using primary data for major emission sources so that the GHG emissions related to theproduct reflect the actual operation mode. Even when primary data are obtained, an appropriate calculation
methodology should be selected according to the emission source or target gas. This section presents examples of theGHG emission calculation methodology for each emission source and target gas (especially carbon dioxide, methane,and nitrous oxide).
5

Chapter 3
Calculation of product Carbon Intensity (CI)This chapter explains the calculation method of the product CI that should be reported through this Guideline,
along with the basic ideas for carbon dioxide capture, utilization, and storage (CCUS) and carbon crediting.
１.CI calculation
The Guideline calculates the product CI according to the CFP calculation method to enable multiple stakeholders tocompare the product CI for different lifecycle stages. The calculation is done using the following equation:
𝑃𝑟𝑜𝑑𝑢𝑐𝑡 𝐶𝐼 (𝐶𝑎𝑟𝑏𝑜𝑛 𝐼𝑛𝑡𝑒𝑛𝑠𝑖𝑡𝑦)＝⚫

𝑃𝑟𝑜𝑑𝑢𝑐𝑡 𝐺𝐻𝐺 𝑒𝑚𝑖𝑠𝑠𝑖𝑜𝑛―𝑒𝑚𝑖𝑠𝑠𝑖𝑜𝑛 𝑑𝑒𝑑𝑢𝑐𝑡𝑖𝑜𝑛
𝑃𝑟𝑜𝑑𝑢𝑐𝑡 𝑒𝑛𝑒𝑟𝑔𝑦 𝑐𝑜𝑛𝑡𝑒𝑛𝑡 𝑜𝑟 𝑤𝑒𝑖𝑔ℎ𝑡

Product GHG emission:"feedstock production", "feedstock transportation", and "production process" should be separately calculated.

⚫

Emission deduction:
Refer to Chapter 3.2 ” Emission deduction”⚫

Product energy content:
Unit: MJ. Heating value should be unified to lower heating value (LHV)⚫

Product weight:
Unit: metric ton

２. Emission deduction
As a countermeasure against global warming, the environmental value of products such as LNG, hydrogen, andammonia need to be appropriately determined. To ensure this, a GHG emission calculation and reporting method thatreflects the actual operating mode is essential. This section describes the basic concept of CCUS and carbon credits.
Carbon dioxide Capture and Storage（CCS）
When carbon dioxide is captured and stored within the boundary, it can be subtracted from the product CI value,
given that the deduction calculation methodology is appropriate. In addition, refer to JOGMEC's guideline, which
illustrates the calculation method for carbon storage amounts for CCS projects.
Carbon dioxide Capture and Utilization（CCU）
If carbon dioxide is captured and utilized in a product, it can be subtracted from the product CI value, given that thededuction calculation methodology is appropriate. For example, if carbon dioxide is used to produce a carbonrecycled product, it needs to be assured that the product can become an alternative to natural gas-based products, orthat the fixed carbon dioxide will not be rereleased into the atmosphere after a short period.
6

Carbon credit
The credibility of applying carbon credits to the product CI is still under discussion. In contrast, there are existing
crediting mechanisms established by governments where credits are awarded under an appropriate methodology andmanagement system that increases the credibility of credits for emission deduction.

7

Appendix: Table of contents of GHG/CI guideline
Introduction ....................................................................................................................................... 1
1. Background / Introduction .......................................................................................................... 1
2. Feature and structure of guideline .............................................................................................. 3
Chapter 1 Coverage of guideline and data handling ........................................................................... 5
1 Reference standards and guidelines .......................................................................................... 52 Boundaries ................................................................................................................................ 6
2.1 System boundaries ........................................................................................................... 6
2.2 Applicable process flow..................................................................................................... 7
2.3 Cut-off criteria ................................................................................................................... 8
2.4 Allocation .......................................................................................................................... 93 Calculation data ...................................................................................................................... 10
3.1 Data aggregation .............................................................................................................. 10
3.2 Data quality ...................................................................................................................... 10
3.3 Data uncertainty ............................................................................................................... 11
3.4 Data priority ..................................................................................................................... 12
Chapter 2. GHG emission calculation .............................................................................................. 13
1 Greenhouse Gases................................................................................................................... 132 GHG emission source ............................................................................................................. 14
2.1 Combustion ...................................................................................................................... 15
2.2 Flaring / venting ............................................................................................................... 15
2.3 Fugitive emission ............................................................................................................. 16
2.4 Indirect emission .............................................................................................................. 17
3 Calculation of GHG emission ................................................................................................. 17
3.1 Overview of methodology ............................................................................................... 17
3.2 Calculation methodology ................................................................................................. 19
3.3 Combustion ...................................................................................................................... 20
3.4 Flaring / venting ............................................................................................................... 22
3.5 Fugitive emission ............................................................................................................. 23
3.6 Indirect emission .............................................................................................................. 24
4 Methane leakage ..................................................................................................................... 24
5 Production process flow ......................................................................................................... 25
5.1 Feedstock production ....................................................................................................... 26
5.2 LNG ............................................................................................................................... 26
5.3 Hydrogen ......................................................................................................................... 27
5.4 Ammonia ......................................................................................................................... 28
6 Selection example of GHG emission methodology ................................................................ 28
8Chapter 3. Calculation of product CI (Carbon Intensity).................................................................. 31
1 CI Calculation ......................................................................................................................... 31
2 Emission reduction ................................................................................................................. 32
2.1 Carbon dioxide Capture and Storage (CCS) .................................................................... 32
2.2 Carbon dioxide Capture, Utilization and Storage (CCU) .............................................. 32
2.3 Carbon credit ................................................................................................................... 329