User’s Guide for Estimating Direct Carbon Dioxide Emissions from Fossil Fuel Combustion Using the State Inventory Tool January 2023


User's Guide for Estimating
Direct Carbon Dioxide
Emissions from Fossil Fuel
Combustion Using the State
Inventory Tool

January 2023

IT

Prepared by:
ICF

Prepared for:

State Energy and Environment Program,
U.S. Environmental Protection Agency

This section of the User's Guide provides instruction on using the CO2 from Fossil Fuel
Combustion (CO2FFC) module of the State Inventory Tool (SIT), and describes the
methodology used for estimating greenhouse gas emissions from fossil fuel combustion at
the state level.

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Module 1 - CO? from Fossil Fuel Combustion Module

January 2023

Table of Contents

1.1	Getting Started	2

1.2	Module Overview	4

1.2.1	Data Requirements	4

1.2.2	Tool Layout	7

1.3	Methodology	7

1.4	Uncertainty	16

1.5	References	16

State Greenhouse Gas Inventory Tool User's Guide for the CO2FFC Module

1.1

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1.1 Getting Started

The Carbon Dioxide from Fossil Fuel Combustion (CO2FFC) module was developed using
Microsoft® Excel 2000. While the module will operate with older versions of Excel, it
functions best with Excel 2000 or later. If you are using Excel 2007 or later, instructions for
opening the module will vary as outlined in the Excel basics below. Before you use the
CO2FFC module, make sure your computer meets the system requirements. In order to
install and run the CO2FFC module, you must have:

• IBM-PC compatible computer with the Windows 95 operating system or later;

• Microsoft® Excel 1997 or later, with calculation set to automatic and macros
enabled;

• Hard drive with at least 20MB free; and

• Monitor display setting of 800 x 600 or greater.

Microsoft Excel Settings

Excel 2003 and Earlier: For the SIT modules to function properly, Excel must be set to
automatic calculation. To check this setting, launch Microsoft Excel before opening the
CO2FFC module. Go to the Tools menu and select "Options..." Click on the "Calculations"
tab and make sure that the radio button next to "Automatic" is selected, and then click on
"OK" to close the window. The security settings (discussed next) can also be adjusted at
this time.

Excel 2007 and Later: For the SIT modules to function properly, Excel must be set to
automatic calculation. Go to the Formulas ribbon and select "Calculation Options." Make
sure that the box next to the "Automatic" option is checked from the pop-up menu.

Microsoft Excel Security

Excel 2003 and Earlier: Because the SIT employs macros, you must have Excel security
set to medium (recommended) or low (not recommended). To change this setting, launch
Microsoft Excel before opening the CO2FFC module. Once in Excel, go to the Tools menu,
click on the Macro sub-menu, and then select "Security" (see Figure 1). The Security pop-
up box will appear. Click on the "Security Level" tab and select medium. When set to high,
macros are automatically disabled; when set to medium, Excel will give you the choice to
enable macros; when set to low, macros are always enabled.

When Excel security is set to medium, users are asked upon opening the module whether to
enable macros. Macros must be enabled in order for the CO2FFC module to work. Once
they are enabled, the module will open to the control worksheet. A message box will
appear welcoming the user to the module. Clicking on the "x" in the upper-right-hand
corner of the message box will close it.

Excel 2007 and Later: If Excel's security settings are set at the default level a Security
Warning appears above the formula box in Excel when the CO2FFC module is initially
opened. The Security Warning lets the user know that some active content from the
spreadsheet has been disabled, meaning that Excel has prevented the macros in the
spreadsheet from functioning. Because SIT needs macros in order to function properly, the
user must click the "Options" button in the security message and then select, "Enable this
content" in the pop-up box. Enabling the macro content for the SIT in this way only enables

State Greenhouse Gas Inventory Tool User's Guide for the CO2FFC Module

1.2

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Module 1 - CO? from Fossil Fuel Combustion Module January 2023

macros temporarily in Excel but does not change the macro security settings. Once macros
are enabled, a message box will appear welcoming the user to module. Click on the "x" in
the upper right-hand corner to close the message box.

If the Security Warning does not appear when the module is first opened, it may be
necessary to change the security settings for macros. To change the setting, first exit out
of the CO2FFC module and re-launch Microsoft Excel before opening the CO2FFC module.
Next, click on the Microsoft Excel icon in the top left of the screen. Scroll to the bottom of
the menu and select the "Excel Options" button to the right of the main menu. When the
Excel Options box appears, select "Trust Center" in left hand menu of the box. Next, click
the gray "Trust Center Settings" button. When the Trust Center options box appears, click
"Macro Settings" in the left hand menu and select "Disable all macros with notification."
Once the security level has been adjusted, open the Stationary Combustion module and
enable macros in the manner described in the preceding paragraph.

Viewing and Printing Data and Results

The CO2FFC module contains some features to allow users to adjust the screen view and the
appearance of the worksheets when they are printed. Once a module has been opened, you
can adjust the zoom by going to the Module Options Menu, and either typing in a zoom
percentage or selecting one from the drop down menu. In addition, data may not all appear
on a single screen within each worksheet; if not, you may need to scroll up or down to view
additional information.

You may also adjust the print margins of the worksheets to ensure that desired portions of
the CO2FFC module are printed. To do so, go to the File menu, and then select "Print
Preview." Click on "Page Break Preview" and drag the blue lines to the desired positions
(see Figure 2). To print this view, go to the File menu, and click "Print." To return to the
normal view, go to the File menu, click "Print Preview," and then click "Normal View."

Figure 1. Changing Security Settings

E3 Microsoft Excel - Bookl

Sj File Edit Vie

View Insert Format

Tools | Data Window Help

v' Spelling,..
^ Research..,
*$> Error Checking..,

Shared Workspace...

Share Workbook...

Track Changes

Compare and Merge Workbooks,..

Protection

Online Collaboration

Goal Seek...

Scenarios,,.

Formula Auditing

Add-Ins.,,

AutoCorrect Options,,,
Customize.,,

Options...

I Macros..,

Record New Macro...

.£] Visual Basic Editor Alt+Fll

Microsoft Script Editor Alt+Shift+Fll

Figure 2. Adjusting Print Margins

Q State Inventory Tool - C02 Emissions from Combustion of Fossil Fuel

SJ File Edit Module Options

Use the Default? (Check for Yes) |

Clear/Select All Defaults

Caibon Contents (lbs Caibon million Btu

Drag cursor to
resize page

Asphalt and Road 0
Aviation Gasoline
Distillate Fuel

Motor Gasoline
Residual Fuel
Misc. Petro Products
Feedstocks, Naphtha
Feedstocks, Other Ois
Pentanes Plus
Petroleum Coke
Still Gas

43.94
variable by year
43.50
43.44
variable by year
variable by year

Default? (Check for Yes)

Clear/5

Clear/Select All Defaults

Pag! 3

State Greenhouse Gas Inventory Tool User's Guide for the CO2FFC Module

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1.2 Module Overview

This User's Guide accompanies and explains the CO2FFC module of the SIT. The SIT was
originally developed in conjunction with EPA's Emissions Inventory Improvement Program
(EIIP) in order to automate the steps states would need to take in developing their own
emission estimates in a manner that was consistent with prevailing national and state
guidelines. The result was a user-friendly and comprehensive set of eleven modules that
help users estimate greenhouse gas emissions at the state level.

Because most state inventories developed today rely heavily on the SIT, User's Guides have
been developed for each of the SIT modules. These User's Guides contain the most up-to-
date methodologies that are, for the most part, consistent with the Inventory of U.S.
Greenhouse Gas Emissions and Sinks (EPA 2022a). Users can refer to the chapters and
annexes of the U.S. Inventory to obtain additional information not found in the SIT or in the
companion User's Guide.

In 2021, EPA began publishing the results of the Inventory of U.S. Greenhouse Gas
Emissions and Sinks disaggregated by U.S. state (EPA 2022b) to make consistent state-
level GHG data available for all states for use by states, researchers, and the general public.
However, EPA recognizes that there will be differences between the state-level estimates
published by EPA and inventory estimates developed by states using the SIT or other tools.
Inventories compiled by states may differ for several reasons, and differences do not
necessarily mean that one set of estimates is more accurate, or "correct." In some cases,
the Inventory of U.S. Greenhous Gas Emissions and Sinks may be using different
methodologies, activity data, and emission factors, or may have access to the latest facility-
level information through the Greenhouse Gas Reporting Program (GHGRP). In other cases,
because of state laws and regulations, states may have adopted accounting decisions that
differ from those adopted by UNFCCC and IPCC to ensure comparability in national reporting
(e.g., use of different category definitions and emission scopes consistent with state laws
and regulations). Users of state GHG data should take care to review and understand
differences in accounting approaches to ensure that any comparisons of estimates are
equivalent or an apples-to-apples comparison of estimates.

The CO2FFC module calculates carbon dioxide (CO2) emissions from the fuel types shown in
Table 1 by end-use sector. While the module provides default data for fuel types
(depending on availability), users are encouraged to use state-specific data, where
available. If using outside data sources, or for a more thorough understanding of the tool,
please refer to the following discussion for data requirements and methodology.

1.2.1 Data Requirements

To calculate CO2 emissions from fossil fuel combustion,1 the following data are required:

• Fossil fuel energy and non-energy consumption by fuel type and sector (non-energy
consumption applies only to the industrial sector);

1 For this discussion, CO2 emissions from fossil fuel combustion include all of the carbon in fuels that is
either immediately oxidized or oxidized within a short time period (i.e., less than 20 years). It thus
includes carbon in the form of gases, like carbon monoxide. It also includes short-lived products that
will be burned after use or decompose quickly.

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• Carbon content coefficients;

• Carbon stored in products; and

• Percentage of carbon oxidized during combustion.

Because the carbon content of fossil fuels varies by fuel type, it is necessary to compile
consumption data for each type of fuel (the recommended list of fuels is provided in Table
D-

Energy consumption statistics should be collected on
an energy basis—preferably in British thermal units
(Btu). Statistics providing energy consumption data
in other units, such as barrels or tons, may be used,
but require conversion to Btu by using the heat
content of the specific fuel. If the conversion to
energy units is necessary, the heat contents that
were used should be documented (default heat
contents are provided in the CO2FFC module).

Please note that even data given in Btu may be
preceded by a prefix indicating order of magnitude
(i.e. thousand, million, billion). For a better
understanding of the quantity prefixes used with Btu,
refer to Box 1.

Box 2: Caution When Using Non-Default Fuel Consumption Data

If you decide to use fuel consumption data that is different from the default, please be aware of
the following possible data problems:

In some cases (e.g., the default EIA's State Energy Consumption, Price, and Expenditure
Estimates (EIA/SEDS) data) fuel consumption statistics can include data that is at odds with the
methodology used in the CO2FFC module. For example, SEDS motor gasoline consumption
includes ethanol that is blended into gasoline. Ethanol is not a fossil fuel, and thus the default
data in the CO2FFC module has been adjusted to remove the portion of blended gasoline known
to be ethanol. If you use external data sources, be sure to determine whether ethanol or other
biofuels (e.g., biodiesel) are included in total consumption for any particular fuel type. If so,
you must subtract the biofuel portion before entering the data into the CO2FFC module. State
ethanol data can be obtained from the Federal Highway Administration's annual Highway
Statistics report (FHWA 2021) and are taken into account with default data provided in the
CO2FFC module.

Users should also be aware of double counting. For example, EIA's SEDS data for industrial coal
consumption includes coal used to make synthetic natural gas, which is accounted for in both
industrial coal and natural gas consumption data. This double-counting issue has been
corrected for in the default dataset contained in the CO2FFC module; similar adjustments may
need to be made to outside data sources. State-specific natural gas data can be obtained from
Table 12 of EIA's Historical Natural Gas Annual EIA (EIA 2001) and Table 8 of EIA's Natural Gas
Annual EIA (EIA 2021) (and is also provided in the CO2FFC module).

Box 1: Energy Units

A British thermal unit (Btu) is the quantity

of heat required to raise the temperature of

one pound of water one degree Fahrenheit

at or near 39.2° Fahrenheit.

Btu

British thermal unit

1 Btu

MBtu

Thousand Btu

lxlO3 Btu

MMBtu

Million Btu

lxlO6 Btu

BBtu

Billion Btu

lxlO9 Btu

TBtu

Trillion Btu

lxlO12 Btu

QBtu

Quadrillion Btu

lxlO15 Btu

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Table 1. Fuel Types Consumed by Sector









Electric

International

Residential

Commercial

Industrial

Transportation

Utilities

Bunker Fuels

Coal

Coal

Coking Coal

Coal

Coal







Other Coal







Natural Gas

Natural Gas

Natural Gas

Natural Gas

Natural Gas



Petroleum:

Petroleum:

Petroleum:

Petroleum:

Petroleum:

Petroleum:

Distillate Fuel

Distillate Fuel

Distillate Fuel

Distillate Fuel

Distillate

Jet Fuel,

Kerosene

Kerosene

Kerosene

Hydrocarbon

Fuel

Kerosene

Hydrocarbon

Hydrocarbon

LPG

Gas Liquids

Residual

Distillate Fuel

Gas

Gas

Motor Gasoline

Motor Gasoline

Fuel

Residual Fuel

Liquids

Liquids

Residual Fuel

Residual Fuel

Petroleum





Motor

Lubricants

Lubricants

Coke





Gasoline

Asphalt/Road

Aviation







Residual Fuel

Oil

Gasoline









Crude Oil

Jet Fuel,









Feedstocks

Kerosene









Misc.

Jet Fuel,









Petroleum

Naphtha









Products











Petroleum











Coke











Pentanes Plus











Still Gas











Special











Naphthas











Unfinished Oils











Waxes











Aviation











Gasoline











Blending











Components











Motor Gasoline











Blending











Components







Other (e.g.

Other (e.g.

Other (e.g.

Other (e.g.

Other (e.g.



geothermal)

geothermal)

geothermal)

geothermal)

geothermal)



Source: U.S. EPA 2022a.

State Greenhouse Gas Inventory Tool User's Guide for the CO2FFC Module

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1.2.2 Tool Layout

Because there are multiple steps to complete within the CO2FFC module, it is important to
have an understanding of the module's overall design. The layout of the CO2FFC module
and the purpose of its worksheets are presented in Figure 3.

Figure 3. Flow of Information in the CO2FFC Module*

Control Worksheet

3. Bulk Data Worksheet

1. Choose <1 State

| Enter energy consumption for all sector by fuel type
Individual Sectoi Worksheets

2. Enter the following variables liy fuel type:

4. Residential

Combustion Efficiencies

i View consumption data and emission factors

Carton Contents jr

5. Commercial

Non-Energy Use Storage Factors

I View consumption data and emission factors

3. Complete Bulk Data Worksheet

6. Transportation

J. View consumption data and emission factors

4. to 9. Complete Sector Worksheets^

7. Electric power

| View consumption data and emission factors

10. View Summary Dot^.

8. Bunker fuels

J, View consumption data and emission factors

11. Export Data

9. Industrial

Enter non-energy consumption for each fuel type
Summary Data

1 Presented in both table and graphical formats in MMTCOjE
Uncertainty

Review information on uncertainty associated with the default data

* These worksheets are the primary worksheets used in the CO2FFC module; subsequent worksheets are used to
populate the default data and are provided for informational purposes only.

1.3 Methodology

This section provides a guide to using the CO2FFC module of the SIT to estimate CO2
emissions from sectors that consume fossil fuels. Within the CO2FFC module, these sectors
are residential, commercial, industrial, transportation, electric power, and bunker fuels.
Because the methodology is similar in
all sectors, a general methodology is
discussed and specific examples for
each sector are provided.

The CO2FFC module automatically
calculates emissions after you enter
energy consumption data (and the
factors on the control worksheet). The tool provides default energy consumption data,
which comes from the EIA's State Energy Consumption, Price, and Expenditure Estimates
(SEDS) EIA (2022).2 However, other state-specific data may be used if available (see Box
3 for suggestions on where to find data).

The CO2FFC module follows the general methodology outlined in the EIIP guidance, however
because of the automation of the calculations within the tool, the order of steps discussed in
this User's Guide do not follow the order of steps discussed within the EIIP guidance
document. This User's Guide provides an overview of the estimation methodology used in

2 These data are available at https://www.eia.gov/state/seds/.

Box 3: State Energy Data Sources

In-state sources, such as state energy commissions or public
utility commissions, should be consulted first. Otherwise,
default data provided by the CO2FFC module may be used.
Fossil fuel statistics should be provided on an energy basis
(e.g., in Btu).

State Greenhouse Gas Inventory Tool User's Guide for the CO2FFC Module

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the CO2FFC module by walking through the following eleven steps: (1) select a state; (2) fill
in the variables used throughout the module; (3) complete the bulk data energy
consumption worksheet; (4) complete the residential sector worksheet; (5) complete the
commercial sector worksheet; (6) complete the transportation sector worksheet; (7)
complete the electric power sector worksheet; (8) complete the bunker fuels sector
worksheet; (9) complete the industrial sector worksheet; (10) review summary information;
and (11) export data.

The general equation used to calculate CO2 emissions from fossil fuel combustion is shown
in Equation 1. The equation used for fuels in the industrial end-use sector is similar, but
includes the non-energy use of fuels, as shown in Equation 2.

Equation 1. General Emission Equation
Emissions (MMTCO2E) =

Consumption (BBtu) x Emission Factor (lbs C/BBtu) x 0.0005 short ton/lbs x Combustion
Efficiency (% as a decimal) x 0.9072 (Ratio of Short Tons to Metric Tons) -r 1,000,000 x

(44/12) (to yield MMTCO2E)

Equation 2. Emission Equation for the Industrial Sector*

Emissions (MMTCO2E) =

(Total Consumption (BBtu) - [Non-Energy Consumption (Bbtu) x Storage Factor (%)])
x Emission Factor (lbs C/BBtu) x Combustion Efficiency (% as a decimal)
x 0.9072 (Ratio of Short Tons to Metric Tons) -r 1,000,000 x (44/12) (to yield MMTCO2E)

* This equation also applies to lubricants consumed in the transportation end-use sector.

Box 4: Treatment of Biofuels in the SIT

The CC^from Fossil Fuel Combustion (CO2FFC) module relies on EIA's SEDS database for state-
level energy consumption data. The SEDS data provides consumption estimates at the state
level for ethanol blended into gasoline. Ethanol is not a fossil fuel, and thus the default data in
the CO2FFC module has been adjusted to remove the portion of blended gasoline known to be
ethanol.

Ideally, biodiesel blended into diesel fuel and other biofuels blended into heating fuels, etc.
should be treated in the same way to avoid counting emissions from non-fossil fuels. However,
due to the lack of state-level data on biofuel consumption, it is not feasible to adjust the default
consumption data in the CO2FFC module to account for these biofuels at this time. The user
should note that this may lead to some overestimation of emissions from fuel consumption by
not considering all blended biofuels. EPA is continuously monitoring data availability and
methodologies that will allow for biofuel adjustments in future versions of the CO2FFC module.

Users are encouraged to adjust the default data and/or enter their own data for diesel and
heating oil consumption if available, especially if the user has access to biodiesel and/or biofuel
consumption within their state. Users should refer to the CO2FFC User's Guide for more
guidance on entering non-default fuel consumption data.

Users are also encouraged to refer to EIA's documentation for SEDS energy consumption data
for more information regarding the fuels included in the CO2FFC module.

State Greenhouse Gas Inventory Tool User's Guide for the CO2FFC Module

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Step (1) Select a State

To begin, select the state you are interested in evaluating. By selecting a state, the rest of
the tool will automatically reset to reflect the appropriate state default data and
assumptions for use in subsequent steps of the tool.

Step (2) Fill in the Variables Used Throughout the Module

Step 2 requires users to select appropriate factors for several key variables necessary for
estimating CO2 emissions from fossil fuel combustion. This can be done by selecting the
default data provided or entering user-specified, fuel-specific data for combustion
efficiencies, carbon contents, and non-energy use storage factors that will be used
throughout the tool. To select the default data, select the "Clear/Select All Defaults" button
for each group of variables (combustion efficiency, carbon content, and non-energy use
storage factors) or check the default box directly to the right of individual yellow input cells.
Note that users may select a default value and later override it if better data becomes
available. To enter state-specific data from other sources, enter values directly into the
yellow input cells. If the user-specific inputs do not match the default data in the control
worksheet (i.e., the default value is overwritten), the text will appear red. See Figure 4 for
locations of the "Clear/Select All Defaults" buttons, individual default check boxes, and
yellow input cells. Information for combustion efficiencies, carbon contents, and non-
energy use storage factors are discussed individually below.

Figure 4. Control Worksheet for the CO2FFC Module

£3 State Inventory Tool - C02 Emissions from Combustion of Fossil Fuel

State Greenhouse Gas Inventory Tool User's Guide for the CO2FFC Module

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Combustion Efficiencies

The first type of required data in the control worksheet is combustion efficiency (percent
carbon oxidized). This percent is applied if the carbon is not completely oxidized during the
combustion of fossil fuels. The fraction oxidized was assumed to be 100 percent for
petroleum, coal, natural gas, and LPG based on guidance from IPCC (2006). If values other
than module defaults are available for state-level combustion, they should be used and
documented. Combustion efficiencies are used throughout the module and are pulled into
each sector's worksheet. Figure 5 presents an example of the combustion efficiency used in
the commercial sector worksheet. If the user-specific inputs do not match the default data
in the control worksheet (i.e., the default value is overwritten), the text will appear red.

Figure 5. Example of Combustion Efficiency Data Applied in the Commercial

Worksheet

E State Inventory Tool - C02 Emissions from Combustion of Fossil Fuel

Carbon Contents

The second type of data required for the control worksheet is the carbon content data,
which is also pulled into the individual sector worksheets (depending on whether the fuel
type is represented in the sector). The carbon content coefficients used in the CO2FFC
module are from the EPA's Inventory of GHG Emissions (EPA 2022a). States are
encouraged to use more detailed data if it is available and well documented. If the user-
specific inputs do not match the default data in the control worksheet (i.e., the default value
is overwritten), the text will appear red.

Carbon content represents the maximum amount of carbon emitted per unit of energy
released, assuming 100 percent combustion efficiency. Coal has the highest carbon content
of the major fuel types, petroleum has roughly 79 percent of carbon per energy as

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compared to coal, and natural gas has about 57 percent. However, carbon contents also
vary within the major fuel types, as noted below:

• Carbon emissions per ton of coal vary considerably depending on the coal's composition
of carbon, hydrogen, sulfur, ash, oxygen, and nitrogen. While variability of carbon
emissions on a mass basis can be considerable, carbon emissions per unit of energy
(e.g., per Btu) vary less.

• The carbon/energy ratio of different petroleum fractions generally correlates with API
(American Petroleum Institute) gravity (Marland and Rotty 1984).3 Lighter fractions
(e.g., gasoline) usually have less carbon per unit energy than heavier fractions (e.g.,
residual fuel oil).

• Natural gas is a mixture of several gases, and the carbon content depends on the
relative proportions of methane, ethane, propane, other hydrocarbons, CO2, and other
gases, which vary from one gas production site to another.

Non-Energy Use Storage Factors

The third and final type of data requested in the control worksheet is the percent of carbon
in each fuel that is stored from non-energy uses. Many fossil fuels have potential non-
energy uses. For example, LPG is used for production of solvents and synthetic rubber; oil
is used to produce asphalt, naphthas, and lubricants; and coal is used to produce coke,
yielding crude light oil and crude tar as by-products that are used in the chemical industry.

However, not all non-energy uses of fossil fuels result in carbon storage. For example, the
carbon from natural gas used in ammonia production is oxidized quickly; many products
from the chemical and refining industries are burned or decompose within a few years; and
the carbon in coke is oxidized when the coke is used. The CO2FFC module provides national
default values for storage factors, but state-level fractions may differ depending on the type
of non-energy uses. Where state-specific estimates are available, their use is preferred, if
adequate supporting documentation is available. If the user-specific inputs do not match the
default data in the control worksheet (i.e., the default value is overwritten), the text will
appear red. Data on the non-energy use storage factor is used in the industrial sector
worksheet (Step 9).

Step (3) Complete the Bulk Energy Consumption Data Worksheet

The energy consumption data entered in the "Bulk Energy Consumption Data" (bulk data)
worksheet feed into the calculation worksheets for each sector. Modifying the consumption
data in this worksheet will change the consumption estimates on each sector calculation
sheet. The default data will automatically be populated in the yellow cells by sector and fuel
type for the selected state. On the bulk data worksheet, presented as an example in Figure
6, the yellow cells indicate where the required energy activity data are entered either
manually or automatically from default data. Default data in the yellow cells on this
worksheet can be overwritten with state-specific data. To revert to default data for all
sectors and fuel types, click on the "Refresh Default Data" button at the top of the

3 Variations in petroleum are most often expressed in terms of specific gravity at 15 degrees Celsius.
The API gravity, where API gravity = 141.5/specific gravity - 131.5, is an indication of the molecular
size, carbon/hydrogen ratio, and hence carbon content of a crude oil.

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worksheet. Click on the "Proceed to Calculation Worksheet" to begin/continue estimating
emissions, or click on the "Return to Control" button to return to the control worksheet.

Figure 6. Example of the Required Energy Consumption Data in the Bulk Data

Worksheet

~ State Inventory Tool - C02FFC Module 12.10.2010v1 .xls

Step (4) through Step (7) View Emission Estimates on Individual Sector
Worksheets (Excluding International Bunker Fuels and Industrial Sector)

With the exception of the industrial sector, the worksheets for each sector have the same
basic set-up. On the residential sector worksheet, presented as an example in Figure 7, the
cells in the first column indicate where the required energy activity data were entered from
the bulk data worksheet. These activity data are converted into CO2 emissions using the
factors entered on the control worksheet, the energy consumption data entered on the bulk
data worksheet, and the formula presented in Equation 1. Click on the orange "Click here
for the bulk data worksheet." button to return to the energy consumption data entry
worksheet.

The activity data used to populate the energy consumption input cells is annual fuel
consumption based on primary fuel type (e.g., coal, petroleum, and natural gas) and
secondary fuel type (e.g., gasoline, residual oil, natural gas, etc.) by sector (e.g.,
residential, commercial, industrial, transportation, and electric utilities). A list of potential
fuel types consumed in each sector is provided in Table 1 and is included in the CO2FFC
module.

The CO2FFC module calculates emissions for each sector by multiplying consumption by the
carbon content and the combustion efficiency to obtain the total carbon oxidized. Then, the
total tons of carbon oxidized are converted into MMTCO2E, by multiplying by the ratio of

State Greenhouse Gas Inventory Tool User's Guide for the CO2FFC Module

1.12

-------
Module 1 - CO? from Fossil Fuel Combustion Module January 2023

metric tons per short ton (0.9072) to obtain metric tons and dividing by 106 and multiplying
by 44/12 to express emissions in MMTCO2E (Equation 1).

Figure 7. Example of the Required Energy Data Applied in the Residential

Worksheet

L] State Inventory Tool - C02 Emissions from Combustion of Fossil Fuel

Step (8) View Estimates on Bunker Fuels Worksheet

Emissions from international bunker fuels are calculated in step 7. International bunker
fuels are fuels used in marine and aviation transport originating in the United States with
international destinations. According to the Revised 1996 IPCC Guidelines, emissions from
international transport should be reported separately as a memo item, instead of allocating
them to a particular country.

Step (9) Complete Non-Energy Use Activity Data on the Industrial Sector
Worksheet

The industrial worksheet is unique because both total energy consumption and total non-
energy consumption are required as inputs to calculate CO2 emissions, shown in Figure 8
(input cells are shown in green). Including activity data on non-energy use allows
calculation of the amount of carbon from these fuels that is stored in non-energy products
for a significant period of time (i.e., more than 20 years). The CO2FFC module estimates
carbon stored in non-energy uses for each state by multiplying the total number of Btu
consumed by the default percent of that fuel type that is used for non-energy purposes, and
then by a storage factor (i.e., the amount of carbon in non-energy uses that typically
remains stored for longer than 20 years, entered in Step 2). This non-energy consumption
is then subtracted from the total consumption to yield the net combustible consumption.
From this point forward, the industrial worksheet functions in the same manner as the other
sector worksheets. The net combustible consumption is multiplied by the carbon content

State Greenhouse Gas Inventory Tool User's Guide for the CO2FFC Module

1.13

-------
Module 1 - CO? from Fossil Fuel Combustion Module

January 2023

and the combustion efficiency to obtain the total carbon oxidized. Then, the total tons of
carbon oxidized are converted into MMTCO2E, by multiplying by the ratio of metric tons per
short ton (0.9072) to obtain metric tons and dividing by 106 and multiplying by 44/12 to
express emissions in MMTCO2E (Equation 2). Click on the orange "Click here for the bulk
data worksheet." button to return to the energy consumption data entry worksheet.

Figure 8. Example of Energy and Non-Energy Consumption Data Applied in the

Industrial Worksheet

£3 State Inventory Tool - C02 Emissions from Combustion of Fossil Fuel

File Edit Module Options

LO_

8. Industrial Consumption and C02 Emissions in Colorado

^/Got

CO; emissions from fossil fuel combustion in the industrial sector are calculated by first subtracting non-energy consumption multiplied by carbon storage
factors from the energy consumption for each fuel type. The resulting combustible consumption for each fuel is then multiplied by a carbon content
coefficient and by the percentage of carbon oxidized during combustion ("combustion efficiency"). The resulting fuel emissions, in pounds of carbon, are
then converted to short tons of carbon and million metric tons of carbon equivalent (MMTCE), then to million metric tons of carbon dioxide equivalent
(MMTCOf), and summed. Note that default emission factors are available through 2008. To facilitate emission calculations for later years, the tool utilizes
2008 emission factors as proxies for emission factors in subsequent years (2009 through 2020). Emission factors for 2009 and beyond will be updated as
soon as new data become available. For further detail on this method, refer to CO/FC Chapter in the User's Guide. Click on the orange "Click here for the
bulk data worksheet." button to return to the energy consumption data entry worksheet.

Go to the MMTCO;
Summary Sheet

Check All Boxes

Industrial Sector

1990

I* Default Non-Energy Consumption Data?

Net combustible

Fuel Tjpe

_ Coking Coal
Othei Coal

21 Misc. Petro Product

22 Petroleum Coke

24 Residual Fuel

25 Still Gas

26 Special Naphthas

27 Unfinished Oils

32 Industrial Sector

1991

W IDefault Non-Energy Consumption Data?:

Net combustible

I0X

)=
)¦

0.00

100.0V

0.000

15,383

57.82

100.0V

444,709

0.403

1.479

o-/.

Required Non-Energy
Consumption Data

0.000

58 X

0.000

0 000

0V.

103

43.97

00.0;-

0.002

0.008

iv.

1,347

43.97

oo.ov

0.027

0.099

0V.

273

42.83

oo.ov

0.005

0.019

206

50 X

1.889

61.34

oo.ov

0.047

172

58 X

42.06

00.05-

0.000

000

108

S0V.

7,338

40.08

00.0V

148

0.134

493

0V.

(1.875)

44.42

oo.ov

(41

•0.038

•

138

5Sv.

43.60

00.05-

0.000

000

0.000

000

Step (10) Review Summary Information

The steps above provide estimates of total carbon in fossil fuels consumed, carbon stored in
non-energy products, and amount of carbon oxidized to CO2. Total carbon emissions are
equal to the total carbon content in fuel, minus carbon stored in non-energy uses, adjusted
for the carbon not oxidized during combustion, and summed over all fuel types and sectors,
for each year. The information is collected on the summary worksheet, displaying results in
MMTCO2E. Figure 9 shows the summary worksheet that sums the emissions from all
sectors in the CO2FFC module. In addition, the results are displayed in graphical format at
the bottom of the summary worksheets.

State Greenhouse Gas Inventory Tool User's Guide for the CO2FFC Module

1.14

-------
Module 1 - CO? from Fossil Fuel Combustion Module

January 2023

Figure 9. Example of the Emissions Summary Worksheet in the CO2FFC Module

Q State Inventory Tool - C02 Emissions from Combustion of Fossil Fuel [i

:[!,

File Edit Module Options























Type a question For help j



A B

c I

D I

E 1

F 1

0 I

H

1

J

K

L



M

N

° 1































_

1

2

California Emissions Summary (MMTC02E)









/Go to the Control
N. Sheet



Review discussion of\.
uncertainty associated
with these results

3

4

5

MMTCO, E

1990

1991

1992

1993

1994

1995

199«

1997

1999

1999



2000

2001

2002

6

Residential

29.59

29.40

27.30

28.89

29.46

26.85

27.03

26.81

32.38

32.04



27.63

28.74

27.85

7

~8~
9

Coal

Petroleum
Natural Gas

0.01
1.44
28.15

0.02
1.70
27.68

0.00
1.21
26.10

0.05
1.27
27.57

0.05
1.26
28.15

0.04
1.22
25.59

0.05
1.03
25.95

0.03
0.96
25.82

0.03
1.56
30.79

0.01
1.46
30.58



0.01
1.43
26.20

0.00
1.10
27.63

0.00
1.12
26.73

10

11

12

13

Commercial
Coal

Petroleum
Natural Gas

18.78
0.04
3.14
15.60

18.89
0.08
3.17
15.65

17.26
0.00
1.75
15.51

15.34
0.25
1.32
13.77

15.74
0.30
1.29
14.15

16.83
0.25
1.64
14.94

14.60
0.34
1.37
12.89

15.21
0.21
1.31
13.69

17.55
0.22
1.52
15.80

14.71
0.05
1.50
13.16



14.18
0.05
1.64
12.49

14.73
0.00
1.49
13.25

13.68
0.00
1.21
12.47

14

15

16

17

Industrial
Coal

Petroleum
Natural Gas

71.91
6.01
34.40
31.50

72.99
5.85
29.46
37.68

73.35
6.00
30.62
36.73

70.79
4.96
28.05
37.77

71.09
5.02
30.37
35.70

69.89
5.36
27.94
36.59

72.51
5.20
29.66
37.65

77.43
5.76
29.86
41.81

74.89
4.02
26.22
44.65

72.85
4.34
27.11
41.40



72.57
4.40
26.81
41.36

74.84
4.34
32.94
37.57

75.22
4.37

30.92

39.93

18

Transportation

203.70

192.56

192.13

189.31

197.85

201.67

204.75

199.11

199.68

204.47



215.57

211.31

223.24

19

20

21

Coal

Petroleum
Natural Gas

202.60
1.10

191.56
1.01

191.31
0.83

188.63
0.68

197.16
0.69

200.61
1.06

203.69
1.06

197.81
1.30

199.11
0.58

203.85
0.62



214.96
0.61

210.57
0.73

222.59
0.65

22

Electric Power

40.34

37.98

45.54

42.00

49.43

37.09

32.77

35.75

39.29

43.22



52.82

57.64

43.65

23

24

25

Coal

Petroleum
Natural Gas

1.78
4.16
34.40

2.41
1.30
34.27

2.53
1.21
41.80

2.63
2.58
36.80

2.52
2.66
44.26

2.21
2.01
32.86

1.89
2.33
28.55

1.70
1.82
32.23

1.86
2.23
35.20

2.05
1.98
39.18



2.05
2.47
48.30

1.96
2.79
52.88

2.13
2.18
39.35

26

27

International Bunker Fuels
Petroleum



0.23
0.23

0.13
0.13

0.11
0.11

0.09
0.09

0.11
0.11

0.11
0.11

0.11
0.11

0.10
0.10

0.11
0.11



0.08
0.08

0.10
0.10

0.10
0.10

28

29

30

31

TOTAL
Coal

Petroleum
Natural Gas

364.32
7.84
245.74
110.74

351.81
8.35
227.18
116.28

355.59
8.53
226.09
120.96

346.34
7.90
221.85
116.59

363.57
7.89
232.74
122.95

352.33
7.86
233.43
111.04

351.67
7.48

238.09

106.10

354.30
7.69
231.77
114.84

363.79
6.14
230.64
127.02

367.29
6.46
235.90
124.94

382.77
6.50
247.32
128.96

387.25
6.30
248.89
132.06

383.64
6.50
258.02
119.12

~32~

33

34

35



Multi-Sector Charts











Individual Sector Charts



I	













	[















II h < ~ m\ Control / Residential / Commercial / Industrial / Transoortation / Electric Power / Bunker Fuels / Summarv-MMTCE \ Summarv-MMTC02E / l< I

Step (11) Export Data

The final step is to export the summary data. Exporting data allows the estimates from
each module to be combined later by the Synthesis Module to produce a comprehensive
greenhouse gas inventory for the state.

To access the "Export Data" button, return
to the control sheet and scroll down to the
bottom (11). Click on the "Export Data"
button and a message box will open that
reminds the user to make sure all steps of
the module have been completed. If you
make any changes to the CO2FFC module
later, you will then need to re-export the
results.

Note: the resulting export file should not be
modified. The export file contains a summary
worksheet where users can view the results, as well as a
separate data worksheet with an unformatted version of
the results; this data worksheet contains the information
that is exported to the Synthesis Tool, and it is especially
important that users do not modify it. Adding/removing
rows, moving data, or making other modifications
jeopardize the ability of the Synthesis Module to
accurately analyze the data.

Clicking "OK" prompts you to save the file.

The file is already named, so you only need to choose a convenient place to save the file.
After the file is saved, a message box will appear indicating that the data was successfully
exported.

State Greenhouse Gas Inventory Tool User's Guide for the CO2FFC Module

1.15

-------
Module 1 - CO? from Fossil Fuel Combustion Module

January 2023

While completing the modules, you are encouraged to save each completed module; doing
so will enable you to easily make changes without re-running it entirely.

Following data export, the module may be reset and run for an additional state.
Alternatively, you may run the remaining modules of the State Inventory Tool to obtain a
comprehensive profile of emissions for your state.

1.4 Uncertainty

In the upper right-hand corner of the summary worksheet is a button: "Review discussion of
uncertainty associated with these results." By clicking on this button, you are taken to a
worksheet that discusses the uncertainty surrounding the activity data and emission factors,
and how the uncertainty estimates for this source category affect the uncertainty of the
emission estimates for your state.

1.5 References

EIA. 2022. State Energy Data 2020 Consumption. Energy Information Administration, U.S.
Department of Energy. DOE/EIA-0214(2020). Available at:
https://www.eia.aov/state/seds/.

EIA. 2021. Natural Gas Annual 2020. Energy Information Administration, U.S. Department
of Energy, Washington, DC. DOE/EIA-0131(20). Available at:
https://www.eia.aov/naturalaas/annual/.

EIA. 2001. Historical Natural Gas Annual 1930-2000. Energy Information Administration,
U.S. Department of Energy. DOE/EIA-Ol 10(00). Available at:

http://www.eia.doe.gov/oil gas/natural gas/data publications/historical natural gas a
nnual/hnga.html.

IPCC. 2006. IPCC Guidelines for National Greenhouse Gas Inventories. The National

Greenhouse Gas Inventories Programme, H.S. Eggleston, L. Buendia, K. Miwa, T. Ngara,
and K. Tanabe, eds.; Institute for Global Environmental Strategies (IGES). Hayama,
Kanagawa, Japan.

Marland, G., and R.M. Rotty. 1984. "Carbon Dioxide Emissions from Fossil Fuels: A
Procedure for Estimation and Results for 1950-1982," Tellus 36b:232-261.

FHWA. 2021. Highway Statistics 1992-2020, Federal Highway Administration, U.S.
Department of Transportation. Available at:
https://www.fhwa.dot.gov/policvinformation/statistics.cfm.

U.S. EPA. 2022a. Inventory of U.S. Greenhouse Gas Emissions and Sinks: 1990 - 2020.
Office of Atmospheric Programs, U.S. Environmental Protection Agency. EPA430-R-21-
005. Available: https://www.epa.gov/ghgemissions/inventorv-us-greenhouse-gas-
emissions-and-sinks-1990-2020

U.S. EPA. 2022b. Inventory of U.S. Greenhouse Gas Emissions and Sinks By State: 1990 -
2020. Office of Atmospheric Programs, U.S. Environmental Protection Agency. Available
at:

State Greenhouse Gas Inventory Tool User's Guide for the CO2FFC Module

1.16

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Module 1 - CO? from Fossil Fuel Combustion Module	January 2023

https://www.epa.aov/svstem/files/documents/202208/StateGHGI Methodology Report
August 2022.pdf

State Greenhouse Gas Inventory Tool User's Guide for the CO2FFC Module

1.17

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