vvEPA
United States
Environmental Protection
Agency
May 2008
EPA430-R-08-006
www.epa.gov/climateleaders
Office of Air and Radiation
CLIMATE LEADERS
GREENHOUSE GAS INVENTORY PROTOCOL CORE MODULE GUIDANCE
Optional Emissions from
Commuting, Business Travel and
Product Transport
CLIMATE
U.S. Environmental Protection Agency
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The Climate Leaders Greenhouse Gas Inventory Protocol is based on the Greenhouse Gas Protocol (GHG Protocol)
developed by the World Resources Institute (WRI) and the World Business Council for Sustainable Development
(WBCSD). The GHG Protocol consists of corporate accounting and reporting standards and separate calculation
tools. The Climate Leaders Greenhouse Gas Inventory Protocol is an effort by EPA to enhance the GHG Protocol to fit
more precisely what is needed for Climate Leaders. The Climate Leaders Greenhouse Gas Protocol consists of the fol-
lowing components:
• Design Principles Guidance
• Core Modules Guidance
• Optional Modules Guidance
All changes and additions to the GHG Protocol made by Climate Leaders are summarized in the Climate Leaders
Greenhouse Gas Inventory Protocol Design Principles Guidance.
For more information regarding the Climate Leaders Program, visit us on the Web at www.epa.gov/climateleaders.
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Commuting, Travel, and Product Transport
Table of Contents
1. Introduction 1
1.1 Greenhouse Gases Included 1
1.2. Optional Mobile Source Activities 1
2. Methods for Estimating Emissions from Employee
Business Travel ... 3
2.1 Passenger Vehicle Business Travel 3
2.2 Rail Business Travel 4
2.3 Bus Business Travel 5
2.4 Airline Business Travel 6
3. Methods for Estimating Emissions from Employee
Commuting 8
3.1 Employee Commuting by Passenger Vehicle 8
3.2 Employee Commuting by Rail 8
3.3 Employee Commuting by Bus 8
4. Methods for Estimating Emissions from Product
Transport 9
4.1 On-Road Vehicle Product Transport 9
4.2 Rail Product Transport 11
4.3 Waterborne Craft and Aircraft Product Transport 12
5. Completeness 14
6. Uncertainty Assessment 15
7. Reporting and Documentation 16
8. Inventory Quality Assurance and Quality Control
(QA/QC) 17
CLIMATE LEADERS GHG INVENTORY PROTOCOL
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Commuting, Travel, and Product Transport
Introduction
Optional emissions are emissions from
sources that are not part of a
Partner's core direct or indirect emis-
sion sources but are a result of the Partner's
activities. These emission sources are not owned
or controlled by the Partner and are considered
to be Scope 3 emissions under the Greenhouse
Gas Protocol developed by the World Resources
Institute (WRI) and the World Business Council on
Sustainable Development (WBCSD). Therefore,
the emission calculation methodologies in this
guidance document may not conform to method-
ologies for Scope 1 and Scope 2 emissions in
other Climate Leaders guidance documents or
from other nationally and internationally accept-
ed protocols.
Although control options surrounding Scope 3
emissions can be limited (i.e., reduction in cor-
porate business travel does not necessarily
reduce GHG emissions from airline flights),
Climate Leaders considers the quantification of
these emissions as a good means of developing a
more comprehensive view of a Partner's climate
impact.
This document presents guidance for estimating
optional GHG emissions resulting from mobile
sources. Specifically, this guidance provides
methodologies to estimate optional GHG emis-
sions from employee commuting, business trav-
el and product transport.
1.1 Greenhouse Gases
Included
Greenhouse gas (GHG) emissions are produced
by mobile sources as fossil fuels are burned.
Carbon dioxide (C02), methane (CH^) and
nitrous oxide (N20) are emitted directly through
the combustion of fossil fuels in different types
of mobile equipment. While C02 can be reason-
ably estimated by applying an appropriate car-
bon content and fraction of carbon oxidized fac-
tor to the fuel quantity consumed, CH4 and N20
emissions depend largely on the emissions con-
trol equipment used (e.g., type of catalytic con-
verter) and distance traveled. Emissions of
these gases also vary with the efficiency and
vintage of the combustion technology, as well as
maintenance and operation practices. A more
detailed discussion of the difference in the cal-
culation methodologies for C02, CH4, and N20
emissions from mobile sources is provided in
the Climate Leaders Guidance for Direct
Emissions from Mobile Combustion Sources.
1.2 Optional Mobile
Source Activities
GHG emissions from mobile sources that may
be optionally reported by a Partner include:
• Employee business travel
• Employee commuting
• Product transport
— Transportation of sold products
— Transportation of purchased materials or
goods
— Transportation of purchased fuels
— Transportation of waste
Partners should report optional GHG emissions
only from the above activities that are relevant
to their business, and for which they have reli-
able information. Also, Partners should only
report optional GHG emissions from sources for
CLIMATE LEADERS GHG INVENTORY PROTOCOL
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SECTION
Commuting, Travel, and Product Transport
which a standardized calculation methodology already included in the Partner's core direct
exists, such as those provided in this document, emissions (e.g., vehicles owned or controlled by
the Partner).
Care should be taken to assure that these
optional mobile emission sources are not
CLIMATE LEADERS GHG INVENTORY PROTOCOL
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Commuting, Travel, and Product Transport
Methods for Estimating Emissions
from Employee Business Travel
Optional GHG emissions associated
with employee business travel are
from ground and air transportation
sources. This guidance specifically addresses
GHG emissions from passenger vehicles, buses,
railways, commuter transportation (e.g., sub-
ways), and commercial airplanes.
2.1 Passenger Vehicle
Business Travel
The GHG emissions from passenger vehicle
business travel are generally from gasoline or
diesel rental and personal vehicles, and taxi
cabs. This protocol provides guidance for esti-
mating C02, CH4, and N20 emissions from pas-
senger vehicle business travel, which are based
on emission factors for cars, light-duty trucks
(e.g., pick-up trucks, sport utility vehicles, etc.),
and motorcycles.
The preferred methodology to estimate C02,
CH4, and N20 emissions from passenger vehicle
business travel is based on fuel usage, vehicle
mileage, and vehicle/control technology.
Partners should refer to the calculation meth-
ods provided in the Climate Leaders Guidance
for Direct Emissions from Mobile Combustion
Sources (Tables A-l, and B-l) to estimate the
C02, CH4, and N20 emissions from these
sources.
If Partners do not have enough data available to
follow the methods in the Climate Leaders
Guidance for Direct Emissions from Mobile
Combustion Sources, then C02, CH4, and N20 emis-
sions may be estimated with information on busi-
ness travel distance. Specifically, emission factors
in this section are provided in Table 1 in terms of
the distance traveled by the vehicle regardless of
the number of passengers (vehicle-mile).
The emission factors for Table 1 were derived
from statistical information of passenger vehicle-
miles, which is provided in Table VM-1 of the
Federal Highway Administration Highway
Statistics 2005 along with C02, CH4, and N,0 emis-
sions data from transportation sector in the U.S.
Greenhouse Gas Emissions and Sinks: 1990-2005.
C02, CH4, and N20 emissions data for cars and
light-duty trucks (i.e., light-duty trucks and other
2-axle, 4-tire vehicles) were obtained from Table
2-17 and C02 data for motorcycles were obtained
from Table A-l 08 of the U.S. Greenhouse Gas
Emissions and Sinks: 1990-2005. CH4 and N20
emissions data for motorcycles reflect the esti-
mates of distance traveled by motorcycles with
and without control technology multiplied by
emissions factors for each configuration (see dis-
cussion of methodology and data sources in
pages A102 to A105 of the U.S. Greenhouse Gas
Emissions and Sinks: 1990-200.5).
Table 1: Emission Factors for Passenger Vehicle Business
Travel (vehicle-mile)
Vehicle Type
Car
Light-duty Truck
Motorcycle
CO2 Emission Factor
(kg CO2/vehicle-mile)
0.364
0.519
0.167
CH4 Emission Factor
(g CH4/vehicle-mile)
0.031
0.036
0.070
N2O Emission Factor
(g N2O/vehicle-mile)
0.032
0.047
0.007
CLIMATE LEADERS GHG INVENTORY PROTOCOL
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SECTION 2
Commuting, Travel, and Product Transport
Equation 1 provides the method to determine
emissions from passenger vehicle business trav-
el in terms of vehicle miles. This equation can
be used for business travel in passenger cars,
light-duty trucks and motorcycles. Total C02-
equivalent emissions are in kg units, vehicle dis-
tance in units of vehicle-mile and other values in
the appropriate units provided in Table 1.
Equation 1: Passenger
Vehicle Business Travel
Emissions (vehicle-mile)
E = VMT * (EFC02 + EFCH4 * 0.021 +
EFN20 * 0.310)
where:
E = Total C02-equivalent Emissions
VMT = Vehicle Miles Traveled
EFC02 = C02 Emission Factor
EFCH4 = CH4 Emission Factor
EFN20 = N20 Emission Factor
0.021 = Conversion Factor
0.310 = Conversion Factor
2.2 Rail Business
Travel
The GHG emissions from rail business travel
are comprised of transit rail (e.g., subway,
tram), commuter rail, and intercity rail (e.g.,
Arntrak). This protocol provides guidance for
estimating C02, CH4, and N20 emissions from
rail business travel.
To estimate C02, CH4, and N20 emissions from
these sources, the Partner should use the emis-
sion factors provided in Table 2. These emission
factors are provided in terms of mass of emis-
sions per passenger-mile.
The emission factors provided in Table 2 were
derived from statistical information of railway
services from Tables 9.10 to 9.12 and Tables A.13
to A. 15 of the Center for Transportation Analysis,
Transportation Energy Data Book: Edition 26. This
annual statistical information (e.g., energy use,
average trip length, etc.) was converted to emis-
sions data by using emission rates from the
Climate Leaders Guidance for Direct Emissions
from Mobile Combustion Sources and Indirect
Emissions from Purchases/Sales of Electricity and
Steam. The conversion process is provided in
Equation 2 for each type of rail system.
The calculation process is provided in Equation
2 for each of the rail type systems. The use of
this equation is appropriate for intercity rail
(e.g., Amtrak), commuter rail, and transit rail
(e.g., trams and subways). Total C02-equivalent
emissions are in kg units, passenger distance in
units of passenger-mile and other values in the
appropriate units provided in Table 2.
Equation 2: Rail Business
Travel Emissions
(passenger-mile)
E = PMT * (EFC02 + EFCH4 * 0.021 *
EF,
N20
0.310)
where:
E = Total C02-equivalent Emissions
E = Passenger Miles Traveled
EFC02 = C02 Emission Factor
EFCH4 = CH4 Emission Factor
EFN20 = N20 Emission Factor
0.021 = Conversion Factor
0.310 = Conversion Factor
CLIMATE LEADERS GHG INVENTORY PROTOCOL
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Commuting, Travel, and Product Transport
SECTION 2
Table 2: CO2, CH4, and N2O Emission Factors for Rail
Business Travel (passenger-mile)
Rail System Type
Intercity Rail
(e.g., Amtrak)
Commuter Rail
Transit Rail (e.g.,
Trams and Subways)
CO2 Emission Factor
(kg CO2/passenger-mile)
0.185
0.172
0.163
CH4 Emission Factor
(g CH4/passenger-mile)
0.002
0.002
0.004
N2O Emission Factor
(g N2O/passenger-mile)
0.001
0.001
0.002
2.3 Bus Business
Travel
The GHG emissions from bus business travel are
primarily due to diesel fired buses and, to a less-
er extent, other fuels such as compressed natu-
ral gas (CNG). This protocol provides guidance
for estimating C02, CH4, and N20 emissions from
bus business travel based on passenger-mile. To
estimate C02, CH4, and N20 emissions from this
source, the Partner should use the emission fac-
tors provided in Table 3. As mentioned previ-
ously, these emission factors are based on the
assumption that the bus travel is conducted in
buses mainly fueled by diesel. If the Partner has
specific fuel information on the bus travel, they
should refer to the Climate Leaders Guidance
for Direct Emissions from Mobile Combustion
Sources.
The emission factors in Table 3 were derived
from statistical information on passenger-mile in
Table VM-1 of the Federal Highway
Administration's Highway Statistics 2005. along
with emissions data from Table 2-17 from the
U.S. Greenhouse Gas Emissions and Sinks:
1990-2005. CH4 and N20 emissions data for bus
business travel were estimated from the values
in Table 2-17 for "Other Trucks and Buses" and
were apportioned based on fuel usage and vehi-
cle type (see discussion of methodology and
data sources in pages A102 to A105 of the U.S.
Greenhouse Gas Emissions and Sinks: 1990-2005).
Equation 3 can be used to determine the emis-
sions from bus business travel. Total C02-equiv-
alent emissions are in kg units, passenger dis-
tance in units of passenger-mile and other val-
ues in the appropriate units provided in Table 3.
Table 3. Emission Factors for Bus Business Travel
(passenger-mile)
CO2 Emission Factor
(kg CO^passenger-mile)
0.107
CH4 Emission Factor
(g CH4/passenger-mile)
0.0006
N2O Emission Factor
(g N2O/passenger-mile)
0.0005
CLIMATE LEADERS GHG INVENTORY PROTOCOL
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SECTION 2
Commuting, Travel, and Product Transport
Equation 3: Bus Business
Travel Emissions
(passenger-mile)
E = PMT * (EFC02 + EFCH4 * 0.021 +
EFN20 * 0.310)
where:
E = Total C02-equivalent Emissions
PMT = Passenger Miles Traveled
EFC02 = C02 Emission Factor
EFCH4 = CH4 Emission Factor
EFN20 = N20 Emission Factor
0.021 = Conversion Factor
0.310 = Conversion Factor
2.4 Airline Business
Travel
The GHG emissions from airline business travel
are divided by flight distance. Specifically, the
airline travel is divided into long, medium, and
short hauls. This protocol provides guidance for
estimating C02, CH4, and N20 emissions from
airline business travel.
To estimate emissions from these sources, the
Partner should use the emission factors provid-
ed in Table 4. These emission factors are provid-
ed in terms of mass of emissions per passenger-
mile. Therefore, the Partner should obtain pas-
senger-mile information for each category of
flight distance and multiply that value by the
appropriate emission factor.
The C02 emission factors provided in Table 4
were derived from an aggregate representation
of typical emissions per passenger mile, Table 9,
UKDEFRA, Guidelines to Defra's Greenhouse Gas
(GHG) Conversion Factors for Company
Reporting, June 2007. The CH4 and N20 emission
factors were derived from statistical information
of passenger-miles from Table 1-37 of the Bureau
of Transportation Statistics, National
Transportation Statistics for 2007 along CH4, and
N20 emissions data from the U.S. Greenhouse
Gas Emissions and Sinks: 1990-2005 (see discus-
sion of methodology and data sources in pages
A102 to A105). These emission factors do not
include additional impacts of radiative forcing.
In cases where Partners do not have informa-
tion on individual flight lengths of airline travel
they may use a single passenger-mile emission
factor for all airline travel based on emissions
per passenger-mile of domestic and internation-
al commercial flights. The Partner should multi-
ply the total passenger-mile traveled by the
value in Table 4 for "Distance Not Known."
These emission factors were derived from statis-
tical information of passenger-mile from Table 1-
37 of the Bureau of Transportation Statistics,
National Transportation Statistics for 2007 along
C02 emissions data from Table A-110 of the U.S.
Greenhouse Gas Emissions and Sinks: 1990-2005.
Equation 4 is used to determine C02 emissions
from aircraft business travel in terms of passen-
ger-mile. Total C02-equivalent emissions are in
kg units, passenger distance in units of passen-
ger-mile and other values in the appropriate
units provided in Table 4.
CLIMATE LEADERS GHG INVENTORY PROTOCOL
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C o
uting. Travel, and Product Transport
SECTION 2
Table 4: Emission Factors for Airline Business Travel
(passenger-mile)
Airline Travel
Distance
Long Haul
(> 700 miles)
Medium Haul
(> 300 and < 700 miles)
Short Haul
(< 300 miles)
Distance Not Known
CO2 Emission Factor
(kg CCVpassenger-mile)
0.185
0.229
0.277
0.271
CH4 Emission Factor
(g CH4/passenger-mile)
0.0104
0.0104
0.0104
0.0104
N2O Emission Factor
(g N2O/passenger-mile)
0.0085
0.0085
0.0085
0.0085
Equation 4: Airline Business
Travel Emissions
(passenger-mile)
E = PMT * (EFC02 + EFCH4 * 0.021 +
EFN20 * 0.310)
where:
E = Total CCVequivalent Emissions
PMT = Passenger Miles Traveled
EFC02 = C02 Emission Factor
EFCH4 = CH4 Emission Factor
EFN20 = N20 Emission Factor
0.021 = Conversion Factor
0.310 = Conversion Factor
CLIMATE LEADERS GHG INVENTORY PROTOCOL
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SECTION 3
Commuting, Travel, and Product Transport
Methods for Estimating Emissions
from Employee Commuting
Optional GHG emissions associated
with employee commuting travel
occur from ground transportation
sources. This guidance specifically addresses
optional GHG emissions from passenger vehi-
cles, buses, railways, and commuter trans-
portation (e.g., subways).
3.1 Employee
Commuting by
Passenger Vehicle
The emissions from employee commuting by
passenger vehicle are primarily from personal
vehicles. This protocol provides guidance for
estimating C02, CH4, and N20 emissions from
employee commuting by passenger vehicle,
which are based on emission factors for cars
and light-duty trucks.
The methodology to estimate C02, CH4, and N20
emissions from employee commuting by passen-
ger vehicle are based on fuel usage, vehicle
mileage, and vehicle/control technology. Refer
to the calculation methods provided in this doc-
ument for passenger vehicle business travel
(Section 2.1 Passenger Vehicle Business Travel)
to estimate the C02, CH4, and N20 emissions
from these sources wherever there is insuffi-
cient data to follow the Climate Leaders
Guidance for Direct Emissions from Mobile
Combustion Sources.
3.2 Employee
Commuting by Rail
The emissions from rail employee commuting
are due to transit rail (e.g. subway, tram), com-
muter rail, and intercity rail (e.g., Amtrak). This
protocol provides guidance for estimating C02,
CH4 and N20 emissions from employee commut-
ing by rail.
The methodology to estimate C02, CH4, and N20
emissions from employee commuting by rail are
based on employee passenger-mile traveled.
Therefore, the Partner should obtain passenger-
mile information per rail system type and multi-
ply that value by the appropriate C02, CH4, and
N20 emission factor. Refer to the calculation
methods provided in this document for rail
business travel (Section 2.2 Rail Business
Travel) to estimate the C02, CH4, and N20 emis-
sions from these sources.
3.3 Employee
Commuting by Bus
The GHG emissions from bus business travel are
primarily due to diesel fired buses and, to a less-
er extent, other fuels such as compressed natu-
ral gas (CNG). This protocol provides guidance
for estimating C02, CH4, and N20 emissions from
bus employee commuting.
The methodology to estimate C02, CH4, and N20
emissions from employee commuting by bus are
based on employee passenger-mile traveled.
Therefore, the Partner should obtain bus pas-
senger-mile information and multiply that value
by the appropriate C02, CH4, and N20 emission
factors. Refer to the calculation methods provid-
ed in this document for bus business travel
(Section 2.3 Bus Business Travel) to estimate
the C02, CH4, and N20 emissions from these
sources.
8
CLIMATE LEADERS GHG INVENTORY PROTOCOL
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Commuting, Travel, and Product Transport
SECTION 4
Methods for Estimating Emissions
from Product Transport
Optional GHG emissions associated
with product transport stem from
ground, air and waterborne trans-
portation sources. This guidance specifically
addresses the optional GHG emissions from pas-
senger vehicles, trucks, railways, aircraft, and
waterborne craft.
EPA's SmartWay Transport Partnership
(SmartWay) has tools available on their Web
site (www.epa.gov/smartway) to help compa-
nies calculate C02 emissions associated with
product transport. These tools also help com-
panies estimate potential emissions reductions
from various strategies, including shipping
more freight with fuel-efficient SmartWay carri-
ers. Partners who are also participating in the
SmartWay program may use the outputs from
the SmartWay tools, as long as Partners identi-
fy the specific data and factors in their
Inventory Management Plan. Partners should
use the methodologies in this document to
estimate CH4 and N20 emissions from any
sources where SmartWay tools are used to
determine C02 emissions.
4.1 On-Road Vehicle
Product Transport
The GHG emissions from on-road vehicle prod-
uct transport include those from gasoline or
diesel, and to a lesser extent, other fuels such
as compressed natural gas (CNG). This protocol
provides guidance for estimating C02, CH4, and
N20 emissions from on-road vehicle product
transport, which are based on emission factors
for passenger vehicles, light-duty trucks (i.e.,
light-duty trucks and other 2-axle, 4-tire vehi-
cles), and medium and heavy-duty trucks (i.e.,
other trucks, single-unit 2-axle, 6-tire or more
trucks, and combination trucks).
The methodology to estimate C02, CH4, and N20
emissions from on-road vehicle product trans-
port is based on fuel usage, vehicle mileage, and
vehicle/control technology. The Partner should
refer to the calculation methods provided in the
Climate Leaders Guidance for Direct Emissions
from Mobile Combustion Sources (Tables A-l and
B-l) to estimate the C02, CH4, and N20 emis-
sions from these sources.
If fuel usage or vehicle type information is not
available, C02, CH4, and N20 emissions may be
estimated based on vehicle-mile for all vehicle
types or ton-mile for medium- and heavy-duty
trucks. Emission factors for estimating emis-
sions based on vehicle mileage are provided in
Table 5.
The emission factors in Table 5 were derived
from statistical information of annual vehicle
distance traveled in miles from Table VM-1 of
the U.S. Department of Transportation, Federal
Highway Administration, Highway Statistics 2005
along with C02, CH4, and N20 emissions data for
the transportation sector from Table 2-17 of the
U.S. Greenhouse Gas Emissions and Sinks:
1990-2005. CH4 and N20 emissions data for
medium and heavy-duty trucks (i.e., other
trucks and buses) from Table 2-17 of the U.S.
Greenhouse Gas Emissions and Sinks, 1990-2005,
was apportioned based on fuel usage and vehi-
cle type (see discussion of methodology and
data sources in pages A102 to A105 of the U.S.
Greenhouse Gas Emissions and Sinks: 1990-2005).
CLIMATE LEADERS GHG INVENTORY PROTOCOL
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SECTION 4
Commuting, Travel, and Product Transport
Table 5: Emission Factors for On-Road Vehicle Product
Transport (vehicle-mile)
Vehicle Type
Passenger Car
Light-duty Truck
Medium- and Heavy-
duty Truck
CO2 Emission Factor
(kg CO2/vehicle-mile)
0.364
0.519
1.726
CH4 Emission Factor
(g CH4/vehicle-mile)
0.031
0.036
0.021
N2O Emission Factor
(g N2O/vehicle-mile)
0.032
0.047
0.017
The equation used to determine emissions from
passenger vehicle product transport in terms of
vehicle-miles is provided below. Total C02-equiv-
alent emissions are in kg units, vehicle distance
in units of vehicle-mile and other values in the
appropriate units provided in Table 5.
Equation 5: On-Road Vehicle
Product Transport Emissions
(vehicle-mile)
= VMT * (EFC02 H- EFCH4
EFN20 * 0.310)
0.021
where:
E = Total C02-equivalent Emissions
VMT = Vehicle Miles Traveled
EFC02 = C02 Emission Factor
EFCH4 = CH4 Emission Factor
EFN20 = N20 Emission Factor
0.021 = Conversion Factor
0.310 = Conversion Factor
In cases where Partners have information on
ton-mile for on-road vehicle transport from
medium- and heavy-duty trucks, the Partner
should multiply the ton-mile activity data by the
values in Table 6. The emission factors were
derived from statistical information of freight
transport from Table l-46b of the Bureau of
Transportation Statistics, National
Transportation Statistics for 2007 along with
emissions data from the transportation sector
from Table 2-17 of the U.S. Greenhouse Gas
Emissions and Sinks: 1990-2005.
i o
CLIMATE LEADERS GHG INVENTORY PROTOCOL
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Commuting, Travel, and Product Transport
SECTION 4
Table 6. Emission Factors for On-Road Truck Product
Transport (ton-mile)
CO2 Emission Factor
(kg CO^ton-mile)
0.297
CH4 Emission Factor
(g CH4/ton-mile)
0.0035
N2O Emission Factor
(g N2O/ton-mile)
0.0027
The equation used to determine emissions from
on-road vehicle product transport from medium-
and heavy-duty trucks is provided below. Total
C02-equivalent emissions are in kg units, trans-
port distance in units of ton-mile, and other val-
ues in the appropriate units provided in Table 6.
Equation 6: On-Road Truck
Product Transport Emissions
(ton-mile)
E = TMT * (EFC02 + EFCH4 * 0.021 +
EFN20 * 0.310)
where:
E = Total C02-equivalent Emissions
TMT = Ton Miles Traveled
EFC02 = C02 Emission Factor
EFCH4 = CH4 Emission Factor
EFN20 = N20 Emission Factor
0.021 = Conversion Factor
0.310 = Conversion Factor
4.2 Rail Product
Transport
The GHG emissions from rail product transport
are primarily due to diesel freight rail systems.
This protocol provides guidance for estimating
C02, CH4, and N20 emissions from rail product
transport.
The methodology to estimate C02, CH4, and N20
emissions from rail product transport is based
on fuel usage. The Partner should refer to the
calculation methods provided in the Climate
Leaders Guidance for Direct Emissions from
Mobile Combustion Sources (Table A-6, B-l and B-
2) to estimate C02, CH4, and N20 emissions from
these sources.
If fuel usage information is not available, C02,
CH4, and N20 emissions may be estimated using
the emission factors provided in Table 7. These
emission factors were derived from statistical
information of freight transport provided in
Table l-46b of the Bureau of Transportation
Statistics, National Transportation Statistics for
2007, along with freight rail fuel consumption
data provided in Table A. 12 of the Center for
Transportation Analysis, Transportation Energy
Data Book: Edition 26 as well as personal com-
munications with the American Short Line
Railroad Association. In the case of CH4 and N20
emissions, fuel consumption data from the
above sources were converted to emissions
data by using the emission rates in Table A-6 of
the Climate Leaders Guidance for Direct
Emissions from Mobile Combustion Sources.
The methodology for estimating emissions from
rail product transport is provided in the follow-
ing equation. Total C02-equivalent emissions are
in kg units, transport distance in units of ton-
mile and other values in the appropriate units
provided in Table 7.
CLIMATE LEADERS GHG INVENTORY PROTOCOL
1 1
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SECTION 4
Commuting, Travel, and Product Transport
Table 7. Emission Factors for Rail Product Transport
(ton-mile)
CO2 Emission Factor
(kg Oyton-mile)
0.0252
CH4 Emission Factor
(g CH4/ton-mile)
0.002
N2O Emission Factor
(g N2O/ton-mile)
0.0006
Equation 7: Rail Product
Transport Emissions
(ton-mile)
E = TMT * (EFC02 + EFCH4 * 0.021 +
EFN20 * 0.310)
where:
E = Total C02-equivalent Emissions
TMT = Ton Miles Traveled
EFC02 = C02 Emission Factor
EFCH4 = CH4 Emission Factor
EFN20 = N20 Emission Factor
0.021 = Conversion Factor
0.310 = Conversion Factor
4.3 Waterborne Craft
and Aircraft Product
Transport
The methodology to estimate C02, CH4, and N20
emissions from waterborne craft and aircraft
product transport is based on fuel usage. The
Partner should refer to the calculation methods
provided in the Climate Leaders Guidance for
Direct Emissions from Mobile Combustion Sources
(Tables A-6, B-l and B-2) to estimate CO,, CH4,
and N20 emissions from these sources.
If Partners do not have enough data available to
follow the methods in the Climate Leaders
Guidance for Direct Emissions from Mobile
Combustion Sources, then C02, CH4, and N20
emissions may be estimated with distance infor-
mation (ton-mile) on waterborne craft or and/or
aircraft product transport. The emission factors
based on ton-mile data are provided in Table 8.
The emissions factors in Table 8 for waterborne
craft reflect freight ton-mile data from Table 1-
46b in National Transportation Statistics 2008
(table was published in July 2007) and calcula-
Table 8: Emission Factors for Waterborne Craft and Aircraft
Product Transport (ton-mile)
Transport Type
Waterborne Craft
Aircraft
CO2 Emission Factor
(kg CO^ton-mile)
0.048
1.527
CH4 Emission Factor
(g CH4/ton-mile)
0.0041
0.0417
N2O Emission Factor
(g N2O/ton-mile)
0.0014
0.0479
1 2
CLIMATE LEADERS GHG INVENTORY PROTOCOL
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Commuting, Travel, and Product Transport
SECTION 4
tions used to develop emissions summarized in
Table A-101 of the Inventory of U.S. Greenhouse
Gas Emissions and Sinks 1990-2006. The
Inventory's passenger- and freight-specific esti-
mates were developed by assuming that all
residual oil-powered ships are engaged in freight
movement; all gasoline-powered vessels are
engaged in passenger transport, and that diesel
powered vessels serve both functions. The
freight component reflects total waterborne
diesel, less diesel associated with recreational
boats, the latter of which reflects estimates from
EPA's NONROAD model. C02 emissions by fuel
type are summarized in Table 3-7 of the
Inventory of U.S. Greenhouse Gas Emissions and
Sinks. Fuel consumption estimates for recre-
ational boats (passenger) and ships and boats
(freight) are shown in Table A-74 of the
Inventory of U.S. Greenhouse Gas Emissions and
Sinks. To compute CH4 and N20 emissions,
these fuel consumption estimates can be multi-
plied by emissions factors shown in Table A-90
of the Inventory of U.S. Greenhouse Gas
Emissions and Sinks.
The emissions factors in Table 8 for commercial
aircraft were taken from ton-mile data from
Table l-46b in National Transportation Statistics
2008 and calculations used to develop Table A-
101 in the Inventory of U.S. Greenhouse Gas
Emissions and Sinks. The passenger- and freight-
specific estimates were developed by determin-
ing the relative weight of passengers and freight
carried on commercial aircraft. As described on
page A-123 of the Inventory of U.S. Greenhouse
Gas Emissions and Sinks, it was assumed that an
average passenger weighs 150 pounds and trav-
els with 50 pounds of luggage; estimates of
freight and mail weight were taken from Bureau
of Transportation Table T-100, available at
www.transtats.bts.gov/Fields.asp?Table_ID=310.
The methodology for estimating emissions for
waterborne craft and aircraft product transport
in terms of ton miles is provided in Equation 8.
Total C02-equivqlent emissions are in kg units,
transportation distance in units of ton-mile and
other values in the appropriate units provided
in Table 8.
Equation 8: Waterborne Craft
and Aircraft Product
Transport Emissions
(ton-mile)
E = TMT * (EFC02 + EFCH4 * 0.021 +
EFN20 * 0.310)
where:
E = Total C02-equivalent Emissions
TMT = Ton Miles Traveled
EFC02 = C02 Emission Factor
EFCH4 = CH4 Emission Factor
EFN20 = N20 Emission Factor
0.021 = Conversion Factor
0.310 = Conversion Factor
CLIMATE LEADERS GHG INVENTORY PROTOCOL
1 3
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SECTION 5
Commuting, Travel, and Product Transport
Completeness
In order for a Partner's corporate GHG inven-
tory to be complete, it must include all
emission sources within the company's
inventory boundaries. See Chapter 3 of the
Climate Leaders Design Principles for detailed
guidance on setting organizational boundaries
and Chapter 4 of the Climate Leaders Design
Principles for detailed guidance on setting oper-
ational boundaries of the corporate inventory.
Organizational boundaries are not typically
applied to optional source reporting. However,
EPA suggests that Partners report all optional
emissions that are applicable with each includ-
ed source category (e.g., employee commuting
emissions for all corporate employees).
Additional optional GHG emission sources not
addressed in this guidance may include station-
ary fuel combustion, purchases of electricity,
HFC emissions from air conditioning equipment
and process or fugitive related emissions of
sources upstream or downstream to the Partner.
Partners should refer to this guidance docu-
ment and to the Climate Leaders core guidance
documents as appropriate. For example, to cal-
culate optional HFC and PFC emissions from
employee commuting vehicle air conditioning
equipment the Partner should refer to the
Climate Leaders Guidance for Direct HFC and
PFC Emissions from Use of Refrigeration and Air
Conditioning Equipment.
As described in Chapter 1 of the Climate Leaders
Design Principles, there is no materiality thresh-
old set for reporting emissions. The materiality
of a source can only be established after it has
been assessed. Partners are strongly encour-
aged to include all sources within their organiza-
tional boundary for which there is verifiable
data when considering optional sources. The
inventory should also accurately reflect the
timeframe of the report. In the case of Climate
Leaders, the emissions inventory is reported
annually and should represent a full year of
emissions data.
1 4
CLIMATE LEADERS GHG INVENTORY PROTOCOL
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C o
uting. Travel, and Product Transport
SECTION 6
Uncertainty Assessment
There is uncertainty associated with all
methods of calculating optional C02
emissions from mobile combustion
sources. As outlined in Chapter 7 of the Climate
Leaders Design Principles, Climate Leaders does
not require Partners to quantify uncertainty as
+/-% of emissions estimates or in terms of data
quality indicators.
Climate Leaders recommends that Partners
attempt to identify any areas of uncertainty in
their optional emissions estimates and make an
effort to use the most accurate data possible.
The accuracy of estimating emissions from fos-
sil fuel combustion in mobile sources is partially
determined by the availability of data on the
amount of fuel consumed or purchased. If the
amount of fuel combusted is directly measured
or metered, then the resulting uncertainty
should be fairly low. Data on the quantity of fuel
purchased should also be a fairly accurate rep-
resentation of fuel combusted, given that any
necessary adjustments are made for changes in
fuel inventory, fuel used as feedstock, etc.
However, uncertainty may arise if only the dol-
lar value of fuels purchased is used to estimate
fuel consumption. If the bottom-up method is
used to determine fuel use, uncertainty may
arise if distance traveled and/or fuel economies
are estimated.
The accuracy of estimating optional emissions
from mobile combustion sources is also deter-
mined by the factors used to convert fuel use
into emissions. Uncertainty in the factors is pri-
marily due to the accuracy with which they are
measured, and the variability of the supply
source.
CLIMATE LEADERS GHG INVENTORY PROTOCOL
1 5
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SECTION 7
Commuting, Travel, and Product Transport
Reporting and Documentation
Partners who choose to report optional
emissions from mobile combustion
sources are required to complete the
Climate Leaders Reporting Requirements. In
order to ensure that estimates are transparent
in Table 9 should be maintained. These docu-
mentation sources should be collected to
ensure the accuracy and transparency of the
related emissions data, and should also be
reported in a Partner's Inventory Management
and verifiable, the documentation sources listed Plan (IMP).
Table 9: Documentation Sources for Optional GHG Emissions
from Mobile Combustion
Vehicle Type
Highway Vehicles
Air Transport
Waterborne Transport
Rail Transport
Documentation Source
Records of vehicle-mile traveled, passenger-mile traveled or ton-
mile of freight transported (must be given by vehicle type)
Distance traveled (passenger-mile), Fuel usage (ton-mile)
Fuel usage (ton-mile)
Distance traveled (passenger-mile traveled or ton-mile of freight
transported)
1 6
CLIMATE LEADERS GHG INVENTORY PROTOCOL
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Commuting, Travel, and Product Transport
SECTION 8
Inventory Quality Assurance and
Quality Control (QA/QC)
Chapter 7 of the Climate Leaders Design
Principles provides general guidelines
for implementing a QA/QC process for
all emission estimates. For optional GHG emis-
sions from mobile combustion sources, the
activity data and emission factors can be veri-
fied using a variety of approaches:
• Fuel energy use data can be compared with
data provided to the Department of Energy
or other EPA reports or surveys.
• If any emission factors were calculated or
obtained from the fuel supplier, these factors
can be compared to U.S. average emission
factors.
Partners should review all activity data (e.g.,
fuel consumption data, distance traveled
estimates), as well as any information used
to develop customized emission factors (e.g.,
location of fuel purchases, aircraft fuel con-
sumption).
Fuel use calculations can be checked
through a comparison of the bottom-up and
top-down approaches. These approaches
are discussed in more detail in the Climate
Leaders Guidance for Direct Emissions from
Mobile Combustion Sources.
Cross checks using back-calculation of fuel
economy can highlight order-of-magnitude
errors.
CLIMATE LEADERS GHG INVENTORY PROTOCOL
1 7
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&EPA
United States
Environmental Protection
Agency
Office of Air and Radiation (6202J)
EPA-430-R-08-006
May 2008
www. epa. gov/climateleaders
Recycled/Recyclable—Printed with Vegetable Oil Based Inks on 100% (Minimum 50% postconsumer) Recycled Paper
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