JCM_ID_AM026_ver01.0
Sectoral scope: 07
Joint Crediting Mechanism Approved Methodology ID_AM026“Introduction of CNG-Diesel Hybrid Equipment to Public Buses”
A. Title of the methodology
Introduction of CNG-Diesel Hybrid Equipment to Public Buses, Version 01.0

B. Terms and definitions
Terms

Definitions

CNG-diesel hybrid equipment

Equipment (i.e. CNG fuel tank, fuel pressure regulator, fuelinjector) which enables diesel engines to combust diesel
fuel and CNG at the same time

C. Summary of the methodology
Items
GHGemission

measures

Summaryreduction Introduction of CNG-diesel hybrid equipment to public buseswith diesel engines enables to replace diesel fuel with CNG,
and also enables to improve fuel efficiency of buses, which leadto GHG emission reductions.

Calculationofemissions

reference Reference emissions are emissions from buses without CNGdiesel hybrid equipment which consume diesel fuel only. They
are calculated with CNG and diesel fuel consumption by
project buses, net calorific value of CNG and diesel fuel, CO2
emission factor of diesel fuel, and fuel efficiency of project bus
and reference bus.

Calculation
emissionsofproject Project emissions are emissions from buses with CNG-diesel
hybrid equipment which consume both CNG and diesel fuel.
They are calculated with CNG and diesel fuel consumption by
project buses, net calorific value of CNG and diesel fuel, andCO2 emission factor of CNG and diesel fuel.
Project emissions from fuel consumption by project fuel trucks
to carry CNG from the supplier of CNG to the CNG stations

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JCM_ID_AM026_ver01.0
Sectoral scope: 07
are excluded from project emissions since the emissions fromfuel trucks to carry diesel fuel in reference scenario areconsidered to be the same as the ones for CNG in project
scenario.
Monitoring parameters

CNG consumption by project busesDiesel fuel consumption by project busesDrive distance of project buses

D. Eligibility criteria
This methodology is applicable to projects that satisfy all of the following criteria.
Criterion 1

CNG-diesel hybrid equipment is newly installed to the public transport buses
which have already been in operation or are newly procured.

E. Emission Sources and GHG types
Reference emissions
Emission sources

GHG types

Diesel fuel consumption by reference buses

CO2

Project emissionsEmission sources

GHG types

Diesel fuel consumption by project buses

CO2CNG consumption by project buses

CO2F. Establishment and calculation of reference emissions
F.1. Establishment of reference emissions
Reference emissions are calculated with CNG consumption and diesel fuel consumption by
project buses, net calorific value of CNG and diesel fuel, CO2 emission factor of diesel fuel,and fuel efficiency of project bus and reference bus.
Fuel efficiency of project bus is determined ex-post based on monitored data, which reflect
actual fuel efficiency. On the other hand, fuel efficiency of reference bus is determined ex-antefrom the following three options in a conservative manner to ensure net emission reductions:2

JCM_ID_AM026_ver01.0
Sectoral scope: 07[Option 1]
Daily data sets of drive distance and diesel fuel consumption of bus i are collected prior to
installation of CNG-diesel hybrid equipment. The highest value (the most efficient value) fromthe measured data sets for at least 60 days is selected and determined as fuel efficiency ofreference bus i.
[Option 2]
A catalogue value of fuel efficiency of bus i which is converted from mono diesel fuelcombustion to CNG-diesel hybrid combustion in the project is determined as fuel efficiency ofreference bus i.
A catalogue value usually shows better fuel efficiency than the one which is calculated for thebus being operated. Therefore, setting a default value of fuel efficiency of reference bus basedon the catalogue values is conservative.
[Option 3]
The default value set in this methodology is applied as fuel efficiency of reference bus i.
The default values are determined from the most recent catalogue values of public buses
manufactured by Japanese manufacturers, which usually show better fuel efficiency than theones which are calculated for the bus being operated, hence conservative.

F.2. Calculation of reference emissions

𝑅𝐸𝑝 = ∑ {[(𝐹𝐶𝑃𝐽,𝐶𝑁𝐺,𝑖,𝑝 × 𝑁𝐶𝑉𝐶𝑁𝐺 ) + (𝐹𝐶𝑃𝐽,𝑑𝑖𝑒𝑠𝑒𝑙,𝑖,𝑝 × 𝑁𝐶𝑉𝑑𝑖𝑒𝑠𝑒𝑙 )] ×𝑖

𝜂𝑃𝐽,𝑖,𝑝} × 𝐸𝐹𝑑𝑖𝑒𝑠𝑒𝑙
𝜂𝑅𝐸,𝑖Where𝑅𝐸𝑝

Reference emissions during the period p [tCO2/p]

𝐹𝐶𝑃𝐽,𝐶𝑁𝐺,𝑖,𝑝

CNG consumption by project bus i during the period p [t/p]*𝑁𝐶𝑉𝐶𝑁𝐺

Net calorific value of CNG [GJ/t]

𝐹𝐶𝑃𝐽,𝑑𝑖𝑒𝑠𝑒𝑙,𝑖,𝑝Diesel fuel consumption by project bus i during the period p [kl/p]

𝑁𝐶𝑉𝑑𝑖𝑒𝑠𝑒𝑙

Net calorific value of diesel fuel [GJ/kl]

𝜂𝑃𝐽,𝑖,𝑝Fuel efficiency of project bus i during the period p [km/l]

𝜂𝑅𝐸,𝑖Fuel efficiency of reference bus i [km/l]

𝐸𝐹𝑑𝑖𝑒𝑠𝑒𝑙CO2 emission factor of diesel fuel [tCO2/GJ]i

Identification number of project buses

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JCM_ID_AM026_ver01.0
Sectoral scope: 07*When CNG consumption by project bus is monitored in units of LSP (Litter Setara Premium),the value is converted in units of tonne [t] with the equation below.
CNG consumption [t] = CNG consumption [LSP] × 0.7218 × 10-3
[Source] Ministry of Energy and Mineral Resources
Fuel efficiency of project bus i during the period p (𝜂𝑃𝐽,𝑖,𝑝 ) is calculated with the followingequation.
𝜂𝑃𝐽,𝑖,𝑝 =𝑇𝐷𝑃𝐽,𝑖,𝑝
𝐻𝐹𝐶𝑃𝐽,𝑑𝑖𝑒𝑠𝑒𝑙,𝑖,𝑝 × 103

𝐻𝐹𝐶𝑃𝐽,𝑑𝑖𝑒𝑠𝑒𝑙,𝑖,𝑝 = ∑ 𝐹𝐶𝑃𝐽,𝐶𝑁𝐺,𝑖,𝑝 × 𝑁𝐶𝑉𝐶𝑁𝐺 ÷ 𝑁𝐶𝑉𝑑𝑖𝑒𝑠𝑒𝑙 + ∑ 𝐹𝐶𝑃𝐽,𝑑𝑖𝑒𝑠𝑒𝑙,𝑖,𝑝𝑖𝑖

Where𝜂𝑃𝐽,𝑖,𝑝Fuel efficiency of project bus i during the period p [km/l]

𝑇𝐷𝑃𝐽,𝑖,𝑝Total drive distance of project bus i during the period p [km/p]

𝐻𝐹𝐶𝑃𝐽,𝑑𝑖𝑒𝑠𝑒𝑙,𝑖,𝑝Hypothetical total diesel fuel consumption by project bus i during theperiod p [kl/p]

𝐹𝐶𝑃𝐽,𝐶𝑁𝐺,𝑖,𝑝

CNG consumption by project bus i during the period p [t/p]

𝑁𝐶𝑉𝐶𝑁𝐺

Net calorific value of CNG [GJ/t]

𝑁𝐶𝑉𝑑𝑖𝑒𝑠𝑒𝑙

Net calorific value of diesel fuel [GJ/kl]

𝐹𝐶𝑃𝐽,𝑑𝑖𝑒𝑠𝑒𝑙,𝑖,𝑝Diesel fuel consumption by project bus i during the period p [kl/p]i

Identification number of project buses

G. Calculation of project emissions

𝑃𝐸𝑝 = 𝑃𝐸𝐶𝑁𝐺,𝑝 + 𝑃𝐸𝑑𝑖𝑒𝑠𝑒𝑙,𝑝
𝑃𝐸𝐶𝑁𝐺,𝑝 = ∑(𝐹𝐶𝑃𝐽,𝐶𝑁𝐺,𝑖,𝑝 × 𝑁𝐶𝑉𝐶𝑁𝐺 × 𝐸𝐹𝐶𝑁𝐺 )𝑖

𝑃𝐸𝑑𝑖𝑒𝑠𝑒𝑙,𝑝 = ∑(𝐹𝐶𝑃𝐽,𝑑𝑖𝑒𝑠𝑒𝑙,𝑖,𝑝 × 𝑁𝐶𝑉𝑑𝑖𝑒𝑠𝑒𝑙 × 𝐸𝐹𝑑𝑖𝑒𝑠𝑒𝑙 )𝑖Where𝑃𝐸𝑝

Project emissions during the period p [tCO2/p]

𝑃𝐸𝐶𝑁𝐺,𝑝Project emissions from CNG consumption by project buses during the periodp [tCO2/p]4

JCM_ID_AM026_ver01.0
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𝑃𝐸𝑑𝑖𝑒𝑠𝑒𝑙,𝑝Project emissions from diesel fuel consumption by project buses during theperiod p [tCO2/p]

𝐹𝐶𝑃𝐽,𝐶𝑁𝐺,𝑖,𝑝

CNG consumption by project bus i during the period p [t/p]

𝑁𝐶𝑉𝐶𝑁𝐺

Net calorific value of CNG [GJ/t]

𝐸𝐹𝐶𝑁𝐺

CO2 emission factor of CNG [tCO2/GJ]

𝐹𝐶𝑃𝐽,𝑑𝑖𝑒𝑠𝑒𝑙,𝑖,𝑝Diesel fuel consumption by project bus i during the period p [kl/p]

𝑁𝐶𝑉𝑑𝑖𝑒𝑠𝑒𝑙

Net calorific value of diesel fuel [GJ/kl]

𝐸𝐹𝑑𝑖𝑒𝑠𝑒𝑙CO2 emission factor of diesel fuel [tCO2/GJ]i

Identification number of project buses

H. Calculation of emissions reductions
𝐸𝑅𝑝 = 𝑅𝐸𝑝 − 𝑃𝐸𝑝
Where
𝐸𝑅𝑝

Emission reductions during the period p [tCO2/p]

𝑅𝐸𝑝

Reference emissions during the period p [tCO2/p]

𝑃𝐸𝑝

Project emissions during the period p [tCO2/p]

I. Data and parameters fixed ex ante
The source of each data and parameter fixed ex ante is listed as below.
Parameter

Description of data

𝑁𝐶𝑉𝐶𝑁𝐺

Net calorific value of CNG [GJ/t]

SourceIn the order of preference:a) value provided by fuelsupplier;b) value measured by the
project participants;c) regional or national default
value; ord)

IPCC

default

value

provided in table 1.2 of Ch.1
Vol.2of2006

IPCC

Guidelines on National GHG
Inventories. Lower value isapplied.

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𝑁𝐶𝑉𝑑𝑖𝑒𝑠𝑒𝑙

Net calorific value of diesel fuel [GJ/kl]

In the order of preference:a) value provided by fuelsupplier;b) value measured by theproject participants;c) regional or national default
value; ord)

IPCCdefault

value

provided in table 1.2 of Ch.1
Vol.2of2006

IPCC

Guidelines on National GHG
Inventories. Lower value isapplied.
𝐸𝐹𝐶𝑁𝐺

CO2 emission factor of CNG [tCO2/GJ]

In the order of preference:a) value provided by fuelsupplier;b) value measured by theproject participants;c) regional or national default
value; ord)

IPCCdefault

value

provided in table 3.2.1 of Ch.3
Vol.2of

2006

IPCC

Guidelines on National GHG
Inventories. Higher value isapplied.
𝐸𝐹𝑑𝑖𝑒𝑠𝑒𝑙CO2 emission factor of diesel fuel [tCO2/GJ]

In the order of preference:a) value provided by fuelsupplier;b) value measured by the
project participants;c) regional or national default
value; ord)

IPCC

default

value

provided in table 3.2.1 of Ch.3
Vol.2of

2006

IPCC

Guidelines on National GHG

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Sectoral scope: 07
Inventories. Lower value isapplied.
𝜂𝑅𝐸,𝑖Fuel efficiency of reference bus i [km/l][Option 1]
Measured data.

Fuel efficiency of reference bus is determined
ex-ante in the following manner.

[Option 2]
Catalogue[Option 1]

valuesof

fuelefficiency provided by bus

Fuel efficiency of reference bus i is determined manufacturer.
based on measured data of bus i prior to
installation of CNG-diesel hybrid equipment.

[Option 3]

Daily data sets of drive distance and diesel fuel The catalogues of public buses
consumption of bus i are collected prior to manufacturedbyJapanese

installation of CNG-diesel hybrid equipment manufacturers.
for at least 60 days. The highest value (the most The default value is revised ifefficient value) from the measured data sets is deemed necessary by the JC.
selected and determined as fuel efficiency ofreference bus i.
[Option 2]
Catalogue value of fuel efficiency of bus iwhich is converted from mono diesel fuelcombustion to CNG-diesel hybrid combustionin the project is determined as fuel efficiencyof reference bus i.
[Option 3]
The default value in the following table in linewith the total displacement is applied as fuelefficiency of reference bus i. (“x” in the table
represents the total displacement of project busi)

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Total

x < 5.2L

5.2L (5,200cc)

displacement(5,200cc)

≤x

𝜂𝑅𝐸,𝑖

6.5

4.7

History of the document
VersionDate

Contents revised

01.0

23 December 2020

Electronic decision by the Joint Committee
Initial approval.

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