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Air and Radiation EPA420-P-05-004
March 2005
User Manual and Technical
Issues of GREET for MOVES
Integration
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EPA420-P-05-004
March 2005
User Manual and Technical Issues of
GREET for MOVES Integration
Assessment and Standards Division
Office of Transportation and Air Quality
U.S. Environmental Protection Agency
Prepared for EPA by
Center for Transportation Research
Argonne National Laboratory
Argonne, Illinois
NOTICE
This technical report does not necessarily represent final EPA decisions or positions.
It is intended to present technical analysis of issues using data that are currently available.
The purpose in the release of such reports is to facilitate the exchange of
technical information and to inform the public of technical developments which
may form the basis for a final EPA decision, position, or regulatory action.
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NOTATION
ACRONYMS AND ABBREVIATIONS
BD biodiesel
BD20 mixture of 20% biodiesel and 80% diesel by volume
CARFG California reformulated gasoline
CD Conventional diesel
CG Conventional gasoline
CH4 methane
CNG compressed natural gas
CO carbon monoxide
CO2 carbon dioxide
DDGS distillers' dried grains and solubles
DME dimethyl ether
DMP dry milling plant
DOE U.S. Department of Energy
EF emission factor
EIA Energy Information Administration
EPA U.S. Environmental Protection Agency
ETBE ethyl tertiary butyl ether
EtOH ethanol
EV electric vehicle
E85 mixture of 85% ethanol and 15% gasoline by volume
E90 mixture of 90% ethanol and 10% gasoline by volume
FCV fuel cell vehicle
FG flared gas
FTD Fischer-Tropsch diesel
FTN Fischer-Tropsch naphtha
GHGs greenhouse gases
GREET Greenhouse Gases, Regulated Emissions, and Energy Use in Transportation
GUI Graphic User Interface
HEV hybrid electric vehicle
HTGR high-temperature gas-cooled reactor
IGCC integrated gasification combined cycle
IPCC Intergovernment Panel on Climate Change
LG landfill gas
LNG liquefied natural gas
LPG liquefied petroleum gas
LSD low-sulfur diesel
LT long-term
LWR light water reactor
MeOH methanol
MOVES MOtor Vehicle Emission Simulator
MTBE methyl tertiary butyl ether
M85 fuel mixture of 85% methanol and 15% gasoline by volume
M90 fuel mixture of 90% methanol and 10% gasoline by volume
N2O nitrous oxide
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NOx
NA
NE U. S .
NG
NGCC
NNA
62
PTW
RFG
SMR
SC>2
SOx
SWU
T&D
TAME
TCWC
TS
VOC
WMP
WTP
WTW
nitrogen oxides
North American
North-Eastern United States
natural gas
natural gas combined cycle
non-North American
oxygen
pump-to-wheel
paniculate matter with diameters of 10 micrometers or less
reformulated gasoline
steam methane reforming
sulfur dioxide
sulfur oxides
separative work units
transportation and distribution
tertiary amyl methyl ether
thermo-chemical water cracking
time series
volatile organic compound
wet milling plant
well-to-pump
well-to-wheel
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GREENHOUSE GASES, REGULATED EMISSIONS, AND ENERGY USE IN
TRANSPORTATION
Graphical User Interface
1. GREETGUI User Guide
1.1 INTRODUCTION
This version of GREETGUI is designed to interact with MOVES, receive input from the user
and conduct simulation studies on energy use and greenhouse gas emissions during the
well-to-pump production and distribution phases of different transportation fuels.
GREETGUI receives from MOVES the fuel types and years to be simulated, and produces
the energy efficiencies and emissions for different pollutants of interest to MOVES. A
flowchart explaining the flow of information between GREETGUI and MOVES is shown in
Figure 1.1 below.
Well-to-pump energy and emissions
in MOVES PROGRAM
User selects simulation year(s)
and fuel types
Pre-Processing Menu
Update well-to-pump rates via GREET
Generate input file for GREETGUI
Run GREETGUI Program
GREETGUI PROGRAM
Load GREET Model
(in the background)
User selects fuel market shares and
Technology options
Generate output file of energy use
and emission rates
Figure 1.1 Information Flow between GREETGUI and MOVES
GREETGUI is a graphical user interface (GUI) developed using Microsoft Visual Basic
6.0. It takes input from the user using option buttons, check boxes and text boxes, and
communicates the user input (in the background) into corresponding input cells of a
hidden Excel program, GREETl_6.xls, known as the GREET model. Finally,
GREETGUI invokes the GREET spreadsheet model (running in the background) to
generate the output results in ASCII format, which are later imported by MOVES to
update the Well-to-Pump (WTP) energy and emission rates.
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This document describes the system requirements to install and run the simulation program
GREETGUI as well as the instructions for using the program. Throughout this document, the
user should note the distinction between GREET, which is the hidden spreadsheet model
running in the background and GREETGUI, which is the graphical user interface (GUI)
between the user and the hidden GREET model. The setup program installs the GREETGUI
program as well as the underlying GREET spreadsheet model in a common folder. The
GREET model is an Excel spreadsheet file marked with the Hidden and Read-Only
properties.
1.2 SYSTEM REQUIREMENTS FOR GREETGUI
GREETGUI works on IBM compatible PCs running Microsoft's Windows 95, Windows 98,
Windows 2000, Windows Millennium Edition (ME), Windows NT, or Windows XP. This
application program will not run on the Windows 3.1 operating system. GREETGUI requires
Microsoft Excel 2000 or higher versions to be installed on the user machine before running
GREETGUI. Microsoft Excel 97 and earlier versions will not work with the GREETGUI
program.
Minimum hardware requirements include: Pentium processor at 166 MHz or higher; at least
64 MB RAM; and at least 30 MB of free space on the hard drive.
Recommended hardware profile: Pentium processor at 400 MHz or higher, 128MB or more
of RAM, 100MB of free hard disk space or more.
1.3 INSTALLING GREETGUI
GREETGUI installation is part of the MOVES setup program. It is recommended that the
user close all other applications before proceeding with the GREETGUI installation. The user
may specify the installation drive letter and the folder name or accept the default drive and
folder name assigned by the installation program. If prompted, please restart your computer
to complete the installation process. The installation program will create shortcut to
GREETGUI on the desktop displaying the program icon (the green Argonne National
Laboratory triangle) and its name.
1.4 RUNNING GREETGUI
Running GREETGUI is initiated from the MOVES program by clicking the "Update
Well-to-Pump" option under the "Pre-Processing" menu, as shown in the flow chart in the
above introduction. In such case, MOVES generates an XML file, which includes the user
selection of simulation years and the fuel pathways to be simulated. This XML file is ported
to GREETGUI. Then GREETGUI loads the GREET spreadsheet model in the background
and displays the default assumptions of GREET parameters for the imported fuel pathways.
-------
GREETGUI runs in three distinct interactive phases with the user: (1) specify Market Shares
of selected fuels for different years of simulation, (2) select/specify Technology Options for
production of selected fuels, and (3) review/change Parametric Assumptions associated with
production and distribution of different fuels. Finally, GREETGUI runs the main GREET
spreadsheet program in the background and exports the output results to an ASCII, tab
delimited file. The GREETGUI output file, which is transparent to the user, contains the
following fields:
a. Year ID (an Integer identifying the year to which the calculations were made)
b. Pollutant ID (an Integer from a set of values used in MOVES)
c. Fuel Subtype ID (an Integer from a set of values used in MOVES)
d. Energy use or emission rate (a floating point number, expressed in Joules of energy
use per Joules of fuel's heating value or grams of pollutant per Joules of fuel's
heating value, as appropriate for each pollutant)
In particular, for this phase of GREET/MOVES integration, energy use is reported for total
energy, fossil energy, and petroleum energy and emissions are reported for CO2, CFLi, and
N2O (the latter two are presented in CO2-equivalent emissions). Furthermore, CO2-equivalent
GHG emissions are calculated with global warming potentials of 1, 23, and 296 for CO2,
CH4, and N2O, respectively, the values for the 100-year time horizon developed by IPCC.
MOVES then imports the GREETGUI output file to update its database of energy use and
emissions. The following are the main steps involved in running the GREETGUI program
interactively with MOVES:
1. GREETGUI session is initiated when it receives a call from the MOVES program.
2. If MOVES is calling GREETGUI for the first time, a message box will advise the
user to open and read a Readme.doc file before using GREETGUI for the first time.
Microsoft Word should be installed on the user's machine to view this document.
E:] This Is The First Time You Are Running GREET GUI _x]
It is recommended that you read the GREETGUI Readme.doc file before
using this software for the first time. It provides a quick introduction on the
use of this program.
If you would like to view this GREETGUI Readme.doc file in the future, it
is located in the GREETGUI Folder on your computer
Note: Microsoft Word must be installed on this machine to view this file and Microsoft Excel
must be installed for GREETGUI to run
Would you like to view the readme file now?
Yes
No
Figure 1.2 First Time Screen
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The GREETGUI program will also advise the user of the location of the Readme.doc
file for future access.
Please take time look at the re
If you would like to view the readme file in the future, it is located
in the GREETGUI program directory at:
C:\program Files\GREETGUI
OK
Figure 1.3 Location of Readme File
A warning window will next display asking the user to close all open excel files
before proceeding with the GREETGUI session. The user must close any open Excel
files before clicking the OK button to continue with the current session; otherwise all
open Excel files will be closed by GREETGUI without saving. This is required for
GREETGUI to run properly since GREETGUI manipulates many of the Excel
features in the background, which may affect or be affected by the execution of other
open Excel sessions. All Excel files will be closed without saving if the user responds
to the warning message by clicking "OK". Alternatively, the user can click the
"Cancel" button to quit the GREETGUI Program and keep all open Excel files
running.
GREETGUI
Please close all open Excel files before running GREETGUI, otherwise they will be closed without saving!
I LlZgiEIZll Cancel |
Figure 1.4 Warning Message to Close All Open EXCEL Sessions
4. If the user clicks "OK" in the warning window, GREETGUI will start loading the
XML input file, created by MOVES, and loads the GREET spreadsheet model in
the background.
5. Next the user will see a window with animated graphics, as GREETGUI is being
initialized.
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Starting GREET.
,,•-1 y-i -7, -/: I"!
v_:i .L\. ,;..• _'i ;.
Figure 1.5 Typical Background Activity Screen
Next, the first interactive phase begins with specifying market shares of selected fuel types.
A new window named "User Options" will open as shown in Figure 1.6. This
window includes selected fuel types passed to GREETGUI by MOVES. The user
may choose the GREET default option, the linear interpolation option, or the user
select option.
iu User Options
GREET Market Shares Options
GREET Default
Market Shares
Reformulated/Conventional Gasoline Market Shares
Low-Sulfur/Conventional Diesel Market Shares
ti-
ff
Linear Interpolation
between Start Year
and End Year Shares
(User Specified)
r
r
LPG Production: N G /Crude Feedstock S hares
Ejhanol Production: Corn/Biomass Feedstock Shares
« Back
_
F Default All
r
r
r
User Specify All
Market Shares
r
r
r
r
F User Specify All
Continue » \\
Figure 1.6 User Options for Market Shares Specifications
It should be noted that the GREET spreadsheet model, running in the background, is
currently designed to simulate different fuel production pathways scenarios based
on estimates in lookup tables for the range of years from 1990 to 2020, arranged in a
five years interval, e.g., 1990, 1995, 2000, etc. (see Figure 1.7). Estimates for
simulation years that are not divisible by 5 are calculated from simple interpolation
between the estimates immediately surrounding them in the GREET lookup tables.
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All simulation years beyond 2020 are assumed to have the same estimates for those
of 2020 in the lookup tables.
5-year Market Share of RFC
period Gasoline
1990 0%
1995 15%
2000 30%
2005 35%
2010 50%
2015 65%
2020 100%
Figure 1.7 Typical Marketshare Lookup Table in GREET
Selecting the GREET Default option allows the user to view the default fuel market
share values in the subsequent windows, but without modifying or changing them.
The Linear Interpolation option allows the user to specify fuel market shares for the
first and last year selected for simulation, and performs simple linear interpolation
for all simulation years in between. Therefore, the Linear Interpolation option is
available only if the number of years selected for simulation is three or more. The
User Select option allows the user to modify and change the fuel market shares for
any of the simulation years as desired. The user is expected to select market share
specification options for the shown fuel types, and then click the "Continue" button
to view the fuel market shares for the selected simulation years.
Note that throughout the GREETGUI session, tips are provided to assist the user
with understanding the options and abbreviations displayed in each window. The
user can move the mouse cursor over any button or selection in the displayed
window to view the tip associated with that button or selection.
7. Next, depending on how many fuel types are passed by MOVES to GREETGUI, one
or more window will appear successively to view and/or modify the market shares of
the selected fuel types for different simulation years. The first and last simulation
years' market shares are specified on the top of each window, while the rest of the
years are specified in a separate table, see Figure 1.8. The user can modify each year's
market share individually, or click the "Interpolate" button to interpolate between the
first and last years' market share values. The user can edit only cells with dark yellow
background. All white cells are calculated automatically as the balance of the market
shares for all simulation years.
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E:] Gasoline and Diesel Fuel Types and Shares
Gasoline Fuel Types and Shares
2050
Diesel Fuel Types and Shares
1999
Year
1999
2000
2001
2002
2003
2004
2005
2006
2007
2008
2009
2010
2050
RFG%
27.0
28.4
29.9
31.3
32.7
34.2
35.6
37.0
38.5
39.9
41.3
42.7
100.0
CG%
73.0
71.6
70.1
68.7
67.3
65.8
64.4
63.0
61.5
60.1
58.7
57.3
0.0
Interpolate Gasoline Shares
Year
1999
2000
2001
2002
2003
2004
2005
2006
2007
2008
2009
2010
2050
LSD % CD %
0.0 100.0
2.0 98.0
3.9 96.1
5.9 94.1
7.8 92.2
9.8 90.2
11.8 88.2
13.7 86.3
15.7 84.3
17.6 82.4
19.6 80.4
21 .6 78.4
100.0 0.0
Interpolate Diesel Shares | ,
..i
! Continue :|
Figure 1.8 Typical Market Shares Screen
The user should click "Continue" to set the market share values for all fuels.
Next, the second phase starts with selecting/specifying technology options associated
with the production of the selected fuels. In this phase, GREETGUI presents the user
with the estimates of the simulation year closest to 2010, since the GREET model has
its best estimates for the year 2010. All other years' estimates are made relative to the
estimate of 2010. The following is detailed description of the logic of "base year"
selection in GREET and the consequent adjustment of estimates for subsequent years:
i.
ii.
in.
IV.
The user starts by selecting one or more simulation years in MOVES.
If the user selects more than one simulation year in MOVES, GREET
picks one of the simulation years as its "base year" for presenting
characteristics of technology options.
Specifically, GREET will pick the user-specified simulation year closest to
2010 as its "base" year, and then display the technology characteristics
assumed in GREET for this "base year".
If the user modifies technologies in the presented base year (which is also
one of the user-specified simulation years - the one closest to 2010), then
GREET makes proportionate modifications to the technology
characteristics for all other simulation years. For example, if the user
changes the share of corn-ethanol production from 50% to 60% for the
year 2010, then all estimates for all simulation years subsequent to 2010
would increase by the same percentage, which is 20% in this case.
-------
It should be noted that GREETGUI does not adjust technology options and estimates
for simulation years before 2010 because of their historical significance.
A window will then open, showing blue tabs for the selected fuel pathways. The
Electricity tab will always appear, regardless of the fuel pathway selections made by
the user. This is because all other fuel pathways use electricity in their production.
There are two types of electricity generation mix, the marginal mix and the average
mix. The marginal mix is that used for modeling electric vehicles (EVs) and
grid-connected hybrid electric vehicles (HEVs). The average mix is that used for the
well-to-pump stage of the fuel cycle. Each blue tab will display the input fields and
options for its corresponding pathway group. It should be noted that, throughout the
GREETGUI program, all the yellow fields are input fields that can be edited/changed
by the user. The user can click or double-click inside the yellow field to modify the
default value, provided by GREET, in that field. It should be noted here that the
estimates shown in the yellow fields are extracted from the GREET lookup tables for
a specific year, which is the base year of simulation as mentioned above.
Although GREET lookup tables are not viewed by the user, any change made by the
user to the base year's default estimate will automatically adjust all of the subsequent
years' default estimates in the lookup tables by the same percentage change made to
the base year's estimate. Holding the mouse cursor above any of the input fields will
display a tool-tip box describing the significance of that field. Figure 1.9 below shows
a typical pathway simulation options screen in GRETGUI.
. Pathways Options for Base Year: 2010
Petroleum
Natural Gas
LPG
Ethanol
iElectiicity!
Biodiesel
Marginal Generation Mix for Transportation Use:
(f U.S. Mix
r NE U.S. Mix
Change Default Generation Mix
(~ CA mix
r User Defined
Average Generation Mix for Stationary Use:
(f U.S. Mix
r NE U.S. Mix
C CAMix Change Default Generation Mix
r User Defined
Advanced Technology Share:
NGCC Turbine for NG Plants:
Advanced Coal Tech. for Coal Plants:
Nuclear Plants for Elec. Generation:
LWR Plants Technology Shares
Gas Diffusion I 25.0 %
Centrifuge | 75.0 %
HTGR Plants Technology Shares
Gas Diffusion I 25.0 %
Centrifuge I 75.0 %
« Back
Continue »
Figure 1.9 Typical Pathway Simulation Options Screen in GRETGUI
10
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9. The Petroleum and Natural Gas tabs have several subgroups of pathways, divided into
convenient sub-tabs, which are displayed in Red, see Figure 1.10. The user must
review all the displayed blue and red tabs before continuing to the next window,
otherwise GREETGUI will remind the user to do so. The user may click the
"Continue" button to proceed, or click the "Back" button to review the earlier phase
of market shares selections. As mentioned earlier, the user can move the mouse cursor
over any button or selection in the displayed window to view the tip associated with
that button or selection.
10. Next, a window named "Simulation Options for Alternative Fuel Blends" will appear.
It allows the user to select the shares of the alternative fuels to blend with gasoline
and diesel fuels. The user may adjust the default values for blend shares shown in the
yellow fields. It should be noted that MOVES does not pass to GREETGUI the shares
of alternative fuels for blending in conventional fuels. Therefore, the alternative fuel
shares which the user can specify in GREETGUI, is disconnected from what is used
in MOVES. The MOVES user should be aware of this disconnection and is advised to
specify alternative fuel shares for blending with gasoline and diesel in GREETGUI
that are consistent with those which are used by MOVES. The user may click the
"Continue" button to proceed, or click the "Back" button to review the technology
options of the previous window.
Pathways Options (or Base Year: 2010
Peti oleum
Natural Gas
LPG
Ethanol
Electricity
Biodiesel
DIESEL: 100.0* Low S ulfur DIE S E L: 0. OX Conventional
GASOLINE: Reformulated
GASOLINE: Conventional
California Reformulated Gasoline
02 Content .
(by Weight): | 2.3% Sulfur
Oxygenate
r MTBE
(? jEtgHJ
r ETBE
r TAME
(" No Oxygenate
Leve|: | 26 ppm
EtOH Feedstock
Corn: | 100.0 %
Woody Biomass: | 0%
Herbaceous Biomass: I %
« Back
Continue »
Figure 1.10 Petroleum Pathways Simulation Options in GRETGUI
11
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E:3 Simulation Options for Alternative Fuel Blends x|
NOTE: Shares used here should be consistent with the shares selected in MOVES
Share of Alternative Fuels for Blending by Volume:
Methanol (for Blending with Gasoline): FTD (for Blending with Diesel):
MeOH: |
Ethanol (for Blending with Gasoline):
EtQH (Low-LevelE10):
EtQH (High-level):
FTD: | 100.0%
BD (for Blending with Biesel):
BD: I 200%
85.0%
Methanol
Ethanol(High-LevelBlend)
Ethanol (Low-Level Blend)
B iodiesel
LSD
CD
« Back
! Continue » i
Figure 1.11 Alternative Fuel Blends Simulation Options Screen
11. After the second phase of technology selecting/specifying is completed, a window,
Figure 1.12, will pop-up offering two options:
-Continue: This takes the user to the third and last phase of GREETGUI, which is
the reviewing/changing of parametric assumptions associated with production and
distribution of the selected fuel types. If clicked, GREETGUI will proceed to view
and/or change the parametric assumptions of the base year. The base year is the
year closest to 2010, for which GREET model has its estimates with the least
uncertainty.
-Review selected scenario options: This allows the user to return to the
beginning of the previous technology selection/specification window, where
changes can be made to previous selections by clicking on the appropriate
pathway tabs and making new selections as desired.
12
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El] Proceed to Key Assumptions for Base Year: 2010
- Selection of scenario options has been completed
- Input of parametric assumptions for the selected scenario options will be next.
Proceed to options of parametric assumptions?
L.¥?* Continue
-Q | Review selected scenario options
Figure 1.12 End of Pathways Simulation Options Screen
12. When the user clicks on the "Continue" button, the program proceeds to the third
phase of key assumptions for the selected fuel pathways and scenarios. A window
displaying the simulation options for the base year's parametric assumptions will
show, see Figure 1.13.
The user is reminded that the GREET spreadsheet model, running in the background,
has estimates of key assumptions in lookup tables for the range of years from 1990 to
2020, arranged in a five years interval. Only the base year's estimates of the key
assumptions will be presented to the user for changing or modification. The
assumptions for all other years in the lookup tables will be adjusted by the same
percentage changes made by the user to the base year's estimates.
Q Parametric Assumptions Options Tor Base Year: 2010 x|
Simulation Options using 2010 as Base Year for Parametric Assumptions
(• Use GREET default assumptions estimates
<~ Revise Base Year assumptions which adjust the assumptions of all years
(~ Revise Base Year assumptions which adjust the assumptions of future years
r
View parametric assumptions for
specific years (select from list)
NOTE: Pressing 5HIFT and clicking
the mouse extends the selection
from the previously selected item
to the current item, Pressing CTRL
and clicking the mouse selects or
deselects an item in the list
! Proceed »
Figure 1.13 Parametric Assumptions Simulation Options
13
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The user may select one of three options: (1) Use GREET default assumptions
estimates; (2) Revise Base Year assumptions which automatically adjust the
assumptions of all years by the same percentage change made to the base year's
estimates; or (3) Revise Base Year assumptions which automatically adjust the
assumptions of future years by the same percentage change made to the base year's
estimates.
Selecting the first option in the above window allows the user to view the GREET
default assumption estimates in the subsequent windows, but without modifying or
changing them. The second option allows the user to revise the base year's estimates
and automatically adjusts all other years' estimates in the GREET lookup tables by
the same percentage change made to the base year's estimate. This case is typical
when the user wants to revise the default estimates in the entire lookup table upward
or downward simply by changing the default estimate of the base year. The third
option allows the user to revise the base year's estimates and automatically adjusts
only the future years' estimates in the GREET lookup tables by the same percentage
change made to the base year's estimate. This case is typical when the user wants to
revise the default estimates only for the base year's estimates and the estimates of all
subsequent years up to 2020, but wants to hold the estimates of the earlier years
(previous to the base year) unchanged at their original default values because of their
historical significance.
Although the user cannot view the GREET lookup tables for the key assumptions,
he/she may check a box to view the parametric assumptions, used by GREET, for any
of the simulation years by selecting those years from the displayed list. The user
should click "Proceed" to continue. More details about GREETGUI handling of the
assumptions for different simulation years are given at the end of this document under
a section entitled "Technical Issues with Running GREETGUI".
13. The key assumptions, listed in table format, will appear in a following window. It
should be noted that GREETGUI displays only the key assumptions for viewing or
modification by the user. Other assumptions used by the GREET model are not
displayed in the tables and cannot be viewed or changed by the user through
GREETGUI. However, the user can always go to the GREET model in Excel to
change any of the parametric assumptions.
14. The key assumptions are displayed in two successive windows, "Fuel Production
Assumptions" and "Feedstock and Fuel Transportation Assumptions." The first
window, "Fuel Production Assumptions", includes a blue tab for each of the fuel
pathways selected is shown in Figure 1.14. The yellow cells in the table may be
edited, by a single-click in the cell, to modify any of the key assumptions of the base
year as desired. After reviewing the fuel production assumptions, the user should click
14
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the "Continue" button to proceed to the "Feedstock and Fuel Transportation
Assumptions" window.
«,. Fuel Production Assumptions -Year: 2010
Petroleum | Natural Gas ] Ethanol ] Electricity]
2
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Transportation Modes | Ocean Tanker Size ]
Fuel/Feedstock
Petroleum
Crude for U.S. Average
CG
RFG
CARFG
CD
Mode Share
Distance (miles)
Mode Share
Distance (miles)
Mode Share
Distance (miles)
Mode Share
Distance (miles)
Mode Share
Distance (miles)
NG-Based Fuel
CNG: NA
MeOH: NNA-NG
FTD: NNA-NG
Mode Share
Distance (miles)
Mode Share
Distance (miles)
Mode Share
Feedstock NG
Transmission
Pipeline _ ,
r Tanker
57.0%
5,080
20.0%
1,700
20.0%
1,700
0.0%
3,900
16.0%
1,450
100.0%
750
100.0%
50.0 3,000
100.0%
« Back
Transportation Distribution
Barge Pipeline
Petroleum
1.0% 100.0%
500 750
4.0% 73.0%
520 400
4.0% 73.0%
520 400
0.0% 95.0%
200 150
6.0% 75.0%
520 400
NG-Based Fuel
40.0% 0.0%
520 600
33.0% 60.0%
Rail Truck Truck
0.0% 0.0%
800 30.0
7.0%
800 30.0
7.0%
800 30.0
5.0%
250 30.0
7.0%
800 30.0
40.0% 10.0%
700 80.0 30.0
7.0%
a
! Continue » l]
Figure 1.15 Typical Transportation Assumptions Screen
16. After all key assumptions have been reviewed or modified; another window, Figure
1.16, will present two options:
E3, Proceed to update parametric assumptions for all years J
- Input of parametric assumptions has been completed
Proceed to update parametric assumptions for all years?
jJjJjDl Continue
Review parametric assumptions
Figure 1.16 End of Parametric Assumptions Screen
Continue: This option allows the user to proceed to the completion of the
GREET simulation. GREETGUI will take the user's selected scenario options,
together with the parametric assumptions, run the main Excel program in the
16
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background for all simulation years, and export the output results in the form
of ASCII, tab delimited file.
Review parametric assumptions: This option allows the user to return to the
parametric assumptions windows and review the selections and/or changes
earlier made in these windows.
17. After GREETGUI completes its run, it generates an output file, Figure 1.17, and the
control goes back to the calling program, MOVES. MOVES then imports the output
file generated by GREETGUI to update its database of energy and emission rates. The
GREETGUI output file, which is transparent to the user, contains the following fields:
a. The first column includes a Year ID (an Integer identifying the year to which
the calculations were made)
b. The second column includes a Pollutant ID (an Integer from a set of values used
in MOVES)
c. The third column includes a Fuel Subtype ID (an Integer from a set of values
used in MOVES).
d. The fourth column includes the Energy use or emission rate (a floating point
number, expressed in Joules of energy use per Joules of fuel's heating value or
grams of pollutant per Joules of fuel's heating value, as appropriate for each
pollutant).
The pollutants in the GREETGUI output file include: total energy use, fossil energy use,
petroleum energy use, CO2 emission rate, CH4 emission rate and N2O emission rate.
File Edit
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Figure 1.17 GREETGUI Output File to MOVES
17
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1.5 TECHNICAL ISSUES WITH RUNNING GREETGUI
1.5.1 System Related Issues:
System Speed Considerations
GREETGUI is a calculation-intensive program. If during a GREETGUI session it appears
that the program execution has frozen up after hitting a "Continue" button, the program
should be allowed sufficient time to complete its calculations before clicking the "Continue"
button again.
1.5.2 Calculation Logistic of Lookup (Time-Series) Tables:
Lookup tables are tables built in the GREET (Excel) model which include values for fuel
market shares, fuel production pathways options, and fuel production and transportation
assumptions between 1990 and 2020, estimated at five-year intervals. For any simulation year
between those years listed in the lookup table, GREETGUI simply uses a linear interpolation
algorithm to calculate the estimate for that particular year. Below are examples of lookup
table for reformulated gasoline (RFG) market shares and production assumptions of
conventional gasoline (CG) refining efficiency.
24.0%
5-year
period
1990
1995
2000
2005
2010
2015
2020
Share of RFG
0%
15%
30%
35%
50%
65%
1 00%
Relative
Efficiency (to
yr2010)
86.0%
5 -year
period
1990
1995
2000
2005
2010
2015
2020
CG Refining
Efficiency
86.5%
86.5%
86.0%
86.0%
86.0%
86.0%
85.5%
Relative
Efficiency (to
yr2010)
100.6%
100.6%
100.0%
100.0%
100.0%
100.0%
99.4%
Figure 1.18 Typical Lookup Tables in GREET
It should be noted that the lookup tables in the GREET model has estimates with the least
uncertainty for the year 2010. All other years' estimates are made relative to the estimate
of 2010. GREETGUI uses three different methods to handle the entries of the lookup
tables depending on whether a table represents fuel market shares, fuel production
pathway (technology) options, or fuel production and transportation (parametric)
assumptions. Those three different methods are described below.
18
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(a) For fuel market share estimates, GREETGUI provides the user with three options.
These options are: GREET default estimates, linear interpolation between first and
last year estimates, or user select market shares for some or all of the simulation
years. If the user selects GREET default, then GREETGUI will show market shares
based on the lookup tables built in the GREET model, but the user won't be able to
change any of the GREET default estimates. Alternatively, the user may select to
calculate the market share estimates based on a linear interpolation between the first
and last year estimates. In such case, the user will be able to change the first and last
year estimates, and GREETGUI will automatically calculate the estimates for all
years in between using a linear interpolation algorithm. If the user selects the option
to specify the market shares, then market share estimates for all years will be
amenable to change by the user.
(b) For fuel production pathway (technology) options, GREETGUI presents the user with
the estimates of the simulation year closest to 2010, since GREET has its best
estimates for the year 2010 as noted above. Therefore, the simulation year closest to
2010 is chosen by GREETGUI as the base year, for which the user may change the
technology options and estimates. It should be noted that any changes made by the
user to the base year estimates would automatically adjust estimates to all subsequent
simulation years (subsequent to the base year) with the same amount of change made
to the base year's estimate. For example, if the user changes the share of LPG
production from natural gas from 50% to 60% for the year 2010, then all estimates for
all simulation years subsequent to 2010 would increase by the same percentage,
which is 20% in this case. GREETGUI does not adjust technology options and
estimates for simulation years before 2010 because of their historical significance.
(c) For fuel production and transportation (parametric) assumptions, GREETGUI
presents the user with three options: use GREET default estimates, revise the
assumptions for base year (closest to 2010), which would automatically adjust
assumptions for all simulation years in GREET lookup tables with the same
percentage change made to the base year's estimate, or revise the assumptions for
base year, which would automatically adjust assumptions for future simulation years
(subsequent to the base year) in GREET lookup tables with the same percentage
change made to the base year's estimate.
For more information on the GREET model and GREETGUI developments, please visit
the Argonne National Laboratory GREET web site: http: //greet. anl. gov/. The user
may also download a standalone version of GREETGUI to evaluate energy and emission
impacts of advanced vehicle technologies and new transportation fuels for the entire
well-to-wheel (WTW) fuel cycle, which includes the well-to-pump (WTP) cycle as well
as the pump-to-wheel (PTW) cycle.
19
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2. GREET Simulation Options
Information on key parametric assumptions and pathway simulation options used in various
fuel-cycle simulations are listed in the following subsections. The GREET methodology for
fuel-cycle simulations is not discussed in this manual. Publications that address GREET
methodology are posted and available for download at the Argonne's National Laboratory
GREET model web site http://www.transportation.anl.gov/publications/index.html. The
following is a list of the key publications relevant to the GREET fuel-cycle model:
1) Wang, M., 2001, Development and Use of GREET 1.6 Fuel-Cycle Model for
Transportation Fuels and Vehicle Technologies, ANL/ESD-TM163, Argonne National
Laboratory, Argonne, 111., Jun.
2) Wang, M., 1999a, GREET 1.5 Transportation Fuel-Cycle Model, Volume 1:
Methodology, Development, Use, and Results, ANL/ESD-39, Vol.1, Argonne National
Laboratory, Argonne, 111., Aug.
3) General Motors Corporation, Argonne National Laboratory, BP, ExxonMobil, and Shell,
2001, Well-to-Wheel Energy Use and Greenhouse Gas Emissions of Advanced
Fuel/Vehicle Systems - a North American Analysis, Jun.
2.1 Market shares of fuel options for given transportation fuels
In GREETGUI, market shares of transportation fuels are presented in tabular form for
different years of simulation selected by the user. This includes: 1) gasoline fuels market
shares, which specify the split between reformulated gasoline (RFG) and conventional
gasoline (CG) market shares; 2) diesel fuels market shares, which specify the split between
low-sulfur diesel (LSD) and conventional diesel (CD) market shares; 3) LPG feedstock
market shares, which specify the split between natural gas (NG) and crude feedstock market
shares; and 4) ethanol feedstock market shares, which specify the split between corn, woody
biomass and herbaceous biomass feedstock market shares, see Figure 2.1.
Market shares in GREETGUI are linked to lookup (time-series) tables which are built in the
underlying GREET spreadsheet model for the above mentioned transportation fuels. The
time-series tables are developed to account for the expected changes in the fuel market shares
over time. Table 2.1 lists the default market shares for the above mentioned six transportation
fuels in GREET. The following paragraphs explains the rationale behind the GREET shares
shown in Table 2.1.
The market shares of reformulated gasoline and conventional gasoline, shown in Table 2.1,
are based on the expected trend that RFG market share will continue to increase over time in
the U.S., and could eventually displace conventional gasoline in the future.
20
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The market shares for low-sulfur diesel, shown in Table 2.1, are based on the requirement
that all diesel fuels to be sold in the U.S. for on-road motor vehicles will have low sulfur
content below 15 ppm by weight beginning 2006.
The market share of NG-based LPG is expected to increase over time at the expense of
crude-based LPG in the U.S., primarily due to the expected increase of LPG imports from
other countries to the U.S.
At present, the ethanol fuel is entirely produced from corn. The GREET model assumes corn
to be the only feedstock for ethanol production until 2020 in the U.S.; since cellulosic
biomass-based ethanol is still in the R&D stage.
iii. User Options
GREET Market Shares Options
GREET Default
Market Shares
Reformulated/Conventional Gasoline Market Shares
Low-Sulfur/Conventional Diesel Market Shares
(f
Linear Interpolation
between Start Year
and End Year Shares
(User Specified)
C
r
User Specify All
Market Shares
c
LPG Production: NG/Crude Feedstock Shares
Ethanol Production: Corn/Biomass Feedstock Shares
« Back
Default All
C
C
r
c
c
User Specify All
! Continue »
Figure 2.1. Transportation fuels market share options
Table 2.1. Default market shares for selected transportation fuels
Year
1990
1995
2000
2005
2010
2015
2020
Gasoline
RFG
0%
15%
30%
35%
50%
65%
100%
CG
100%
85%
70%
65%
50%
35%
0%
Diesel
LSD
0%
0%
0%
0%
100%
100%
100%
CD
100%
100%
100%
100%
0%
0%
0%
21
-------
Year
1990
1995
2000
2005
2010
2015
2020
LPG
Crude
Feedstock
50%
45%
40%
40%
40%
35%
30%
NG
Feedstock
50%
55%
60%
60%
60%
65%
70%
Ethanol
Corn
Feedstock
100%
100%
100%
100%
100%
100%
100%
Woody
Biomass
Feedstock
0%
0%
0%
0%
0%
0%
0%
Herbaceous
Biomass
Feedstock
0%
0%
0%
0%
0%
0%
0%
2.2 Key simulation options for petroleum-based fuel production pathways
2.2.1 Gasoline fuels
For reformulated gasoline, conventional gasoline, and California reformulated gasoline, the
user can select the type of oxygenate for blending into gasoline, and specify their Q^ content
by weight, as shown in Figures 2.2, 2.3 and 2.4, respectively. The types of oxygenate that can
be selected in GREET are: 1) MTBE, 2) EtOH, 3) ETBE or 4) TAME. However, if the user
selects the "no oxygenate" option, the C>2 content will be automatically set to zero.
The default sulfur contents in reformulated gasoline and California reformulated gasoline are
26 ppm and 11 ppm, respectively. Since sulfur content in conventional gasoline is expected to
change over time, time-series tables have been created for the default sulfur content in
conventional gasoline as shown in Table 2.2. It should be noted that MOVES does not pass to
GREETGUI the fuel's sulfur content. Therefore, the sulfur content which the user can specify
in GREETGUI, for any of the fuels listed in Table 2.2, is disconnected from what is used in
MOVES. The MOVES user should be aware of this disconnection and is advised to specify
sulfur content in GREETGUI that is consistent with that which is used by MOVES.
In addition to the differences in their refining efficiencies, the California gasoline and the US
gasoline have different transportation modes and distances of crude oil from oil fields to
refineries. For the California reformulated gasoline pathway, the transportation mode and
distance of crude oil to the California refineries will be used in the simulation.
22
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«L Pathways Options Tor Base Year: 2010
Petroleum Natural Gas
LPG
Bhanol
Electricity
Biodiesel
DIESEL: 100.OX Low Sulfur
DIESEL: O.OX Conventional
GASOLINE: Reformulated
GASOLINE: Conventional
California Reformulated Gasoline
02 Content .
(by Weight): | 2-3%
Oxygenate
rr MTBE
r EtOH
r ETBE
C TAME
C No Oxygenate
Sulfur |
Level: I
26
« Back
I Continue »:l
Figure 2.2. Reformulated gasoline production pathway options
«. Pathways Options For Base Year: 2010
Petroleum Natural Gas
LPG
Ethanol
Electricity
Biodiesel
DIESEL: 100.OX Low Sulfur
DIESEL: O.OX Conventional
GASOLINE: Reformulated
! GASOLINE: Conventional!
California Reformulated Gasoline
02 Content
(by Weight): f" * Level: I » Ppm
C MTBE
r EtOH
C ETBE
r TAME
(• No Oxygenate
« Back
Continue »
Figure 2.3. Conventional gasoline production pathway options
23
-------
,. Pathways Options for Base Year: 2010
I
Peti oleum Natural Gas LPG
DIESEL: 100. OX Low Sulfur
GASOLINE: Reformulated
02 Content .
(by Weight): | 2-0 % =
Oxygenate
C MTEE BOH
ff EtOH
r ETBE
ulf
;v
I I
Bhanol Electricity
DIESEL: O.OX Conventional
GASOLINE: Conventional
el: I « PPm
Biodiesel
California Refoimulated
Gasoline
reedstock
Corn: | 100.0 %
Woody Biomass: I
-------
4t Pathways Options Tor Base Year: 2010
Petroleum Natural Gas LPG
Bhanol Electricity Biodiesel
GASOLINE: Reformulated GASOLINE: Conventional
DIESEL: 100.0X Low
Sulfur
DIESEL: 0.0^ Conventional
California Reformulated Gasoline
Sulfur .
Level:
Location for Use
-------
The default sulfur content in GREET for low sulfur diesel is 11 ppm, regardless of its
location for use. The sulfur content in conventional diesel is expected to change over time,
and therefore, time-series tables have been developed in GREET for the default sulfur content
in conventional diesel, both for U.S. and California locations, as shown in Table 2.2 above.
Note that the sulfur content for conventional diesel is specified in Table 2.2 only from 1990
to 2005, beyond which the sulfur content of conventional diesel does not affect the
calculations since its market share is set to zero, see Table 2.1.
It should be noted that MOVES does not pass to GREETGUI the fuel's sulfur content.
Therefore, the sulfur content which the user can specify in GREETGUI, for any of the fuels
listed in Table 2.2, is disconnected from what is used in MOVES. The MOVES user should
be aware of this disconnection and is advised to specify sulfur content in GREETGUI that is
consistent with that which is used by MOVES.
2.3 Key simulation options for NG-based pathways
The natural gas (NG) based fuels simulated in GREETGUI are compressed natural gas
(CNG), Fitsch-Tropsch Diesel (FTD) and methanol (MeOH). For the CNG and FTD fuels,
GREETGUI presents the user with three options for the feedstock source: 1) North American
natural gas (NA NG), 2) non-North American natural gas (NNA NG), or 3) non-North
American flared gas (FG), as shown in Figures 2.7 and 2.8, respectively. For methanol, in
addition to the above three feedstock sources, the user is presented with landfill gas as a
fourth feedstock option (Figure 2.9). For the non-North America sources to CNG, the
feedstock gas is converted into liquefied natural gas (LNG) for transportation to North
America, where it is gasified. The production plant design types for FTD and methanol in
GREET include three design options: 1) without steam or electricity export, 2) with steam
export, or 3) with electricity export. For the second and third options, the energy and
emission credits from the co-generated steam or electricity are automatically estimated in
GREET.
2.3.1 CNG
The GREET default simulation option for CNG feedstock source is North America natural
gas as shown in Figure 2.7.
2.3.2 FTD
All announced FTD plants so far are outside of North America, mainly due to the high price
of NG in North America. Therefore, the default options for feedstock source and plant design
type in GREET are non-North American NG and without steam or electricity export, as
shown in Figure 2.8.
26
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2.3.3 Methanol
Due to the high NG price in North America, most methanol plants are located outside of
North America. Therefore, the default feedstock source for methanol production in GREET is
non-North American, and the default plant design type is without steam or electricity export,
as shown in Figure 2.9.
iii. Pathways Options For Base Year: 2010
Petroleum
i latin al Gas!
CNG
LPG
T
Ethanol
Methanol
Electricity
Biodiesel
J FTD
Feedstock Source
ff NANG
r NNANG
r NNAFG
« Back
Continue »
Figure 2.7. CNG production pathway options
27
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Si, Pathways Options for Base Year: 2010
T
Petroleum M.itui ,il G,is
CNG
LPG
y
Ethanol
Methanol
Electricity
J IF!
Biodiesel
b;
Feedstock Source
C NANG
Plant Design Type
ff NNANG
C NNAFG
ff without steam or
electricity export
(~ with steam export
f~" with electricity export
« Back
Continue » |
Figure 2.8. FTD production pathway options
. Pathways Options Tor Base Year: 2010
Petroleum N.ilui ,il G,is LPG
CNG y
Feedstock Source
Ethanol
Methanol!
Electricity
Biodiesel
y FTD
r NANG _. , _ . _
Plant Design Type
PNNANG r without steam or
electricity export
r NNAFG
I™ with steam export
r LG
r with electricity export
« Back
Continue »
Figure 2.9. Methanol production pathway options
28
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2.4 Key simulation options for LPG production pathway
LPG can be produced from petroleum refineries and/or NG processing plants. The GREET
model allows the user to select the market share of each LPG feedstock source (see
subsection 2.1 above). For NG-based LPG production pathway, the user can select the
feedstock source for LPG production as 1) North American NG, or 2) non-North American
NG. The default simulation option in GREET is North American NG as the feedstock, see
Figure 2.10.
iii. Pathways Options (or Base Year: 2010
Petroleum
Natural Gas
Ethanol
Electricity
Biodiesel
NG Based Options
Feedstock Source
(f NANG
r NNANG
« Back
Continue »
Figure 2.10. LPG production pathway options
2.5 Key simulation options for ethanol production pathway
Ethanol (EtOH) could be produced from 1) corn, 2) woody biomass, and/or 3) herbaceous
biomass. The GREET model allows the user to select the market share of each ethanol
feedstock source (see subsection 2.1 above).
For corn producing ethanol pathway, GREET includes the following plant design options to
produce fuel ethanol: 1) dry milling plants (DMP), and/or 2) wet milling plants (WMP), see
Figure 2.11. Wet milling plants produce ethanol from corn starch. Other co-products in wet
milling plants include high-fructose corn syrup, glucose, gluten feed, and gluten meal. Dry
milling plants, which are smaller than wet milling plants, are designed exclusively for ethanol
production. In dry milling plants, ethanol is produced from corn starch, while other
29
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constituents of the corn kernel are used to produce distillers' dried grains and solubles
(DDGS). The shares of ethanol production in dry milling and wet milling plants may change
over time. Therefore, time-series tables for plant shares (dry milling vs. wet milling)
contributing to the production of corn-based ethanol were developed in GREET, see Table
2.3.
Process fuels used for dry milling plants and wet milling plants are typically NG and coal.
The share of process fuels for each plant type may also change over time. Time-series tables
for the default shares of process fuels for each plant type were developed in GREET, as
shown in Table 2.3.
In addition to ethanol production, corn-based ethanol plants produce a variety of co-products
as mentioned above. While dry milling plants co-produce DDGS, wet milling plants
co-produce corn gluten feed, corn gluten meal, and corn oil. GREET allocates emissions and
energy use charge between ethanol and its co-products by using either a product displacement
method or a market value-based method. The default method in GREET is the product
displacement method.
Table 2.3. Default shares of plant types and process fuels for corn-ethanol
Year
1990
1995
2000
2005
2010
2015
2020
Share of corn-ethanol
plant type
DMP
30%
33%
67%
68%
70%
70%
70%
WMP
70%
67%
33%
32%
30%
30%
30%
Share of process
fuels for DMP
Coal NG
40% 60%
35% 65%
30% 70%
20% 80%
20% 80%
20% 80%
20% 80%
Share of process fuels
for WMP
Coal NG
50% 50%
50% 50%
40% 60%
40% 60%
40% 60%
40% 60%
40% 60%
30
-------
iii. Pathways Options for Base Year: 2010
Petrolei
Natural Gas
LPG
jEthiinol: Electricity
Biodiesel
Corn Ethanol Options:
Share of Ethanol Plant Type:
DMP: |
WMP:|
Co-Product Credit Calc. Method:
<• Displacement
l~ Market
Share of Process Fuels:
DMP:
NG:|~80io% Coal:| %
WMP:
NG:n^O% Coal:! %
Back
Continue »
Figure 2.11. Ethanol production pathway options
2.6 Key simulation options for electricity generation
Energy use and emissions of electricity generation are needed in GREET for two purposes: 1)
electricity usage in well-to-pump (WTP) activities, and 2) electricity use in electric vehicles
(EVs) and grid-connected hybrid electric vehicles (HEVs). The GREET model calculates
emissions associated with electricity generation from residual oil, NG, coal, and uranium. Of
the various power plants, those fueled by residual oil, NG, and coal produce emissions at the
plant site. Nuclear power plants do not produce air emissions at the plant site. However, other
emissions and energy use associated with the upstream production of uranium and its
preparation stages are accounted for in GREET. Electricity generated from hydropower,
solar, wind, and geothermal sources are treated as zero emission plants in GREET; and are
categorized together in one group named "Others".
GREET has two sets of electricity generation mix: 1) marginal generation mix for
transportation use, which is used for EVs and grid-connected HEVs; and 2) average
generation mix for use in all WTP activities. The user can select a set of electricity generation
mix from one of the following options: 1) U.S. average electricity mix, 2) North-Eastern U.S.
average electricity mix, 3) California electricity mix, or 4) user defined mix. Table 2.4 lists
the default electricity generation mix over time in GREET. Future trends (2005-2020) for
U.S. average electricity mix, North-Eastern U.S. average electricity, and California electricity
mix are based on projections from Energy Information Administration (EIA), DOE.
-------
Sj,. Pathways Options for Base Year: 2010
Petroleum
Natural Gas
LPG
Ethanol
iElectricrtyi
Biodiesel
Marginal Generation Mix for Transportation Use:
(f U.S. Mix
C ME U.S. Mix
Change Default Generation Mix
r CAmix
(~ User Defined
Average Generation Mix for Stationary Use:
(T U.S. Mix
r ME U.S. Mix
(~ CAMix Change Default Generation Mix
(" User Defined
Advanced Technology Share:
NG CCTurbineforNG Plants:
Advanced Coal Tech. for Coal Plants:
Nuclear Plants for Elec. Generation:
LWR Plants Technology Shares
Gas Diffusion | 25.0 %
Centrifuge | 75.0 %
HTGR Plants Technology Shares
Gas Diffusion I 25.0 %
Centrifuge I
« Back
Continue »
Figure 2.12. Electricity generation options
The GREET model include two types of nuclear reactor technologies for electricity
generation, the light water reactor [LWR] and the high-temperature gas-cooled reactor
[HTGR]. The user can select the technology shares of uranium enrichment for each type of
the nuclear reactors. The technologies used for uranium enrichment include gaseous diffusion
and centrifuge. The market share of these two technologies may change over time. Table 2.5
shows the time-series tables for the GREET default shares of gaseous diffusion and
centrifuge technologies used for uranium enrichment. It should be noted that electricity
consumption for uranium enrichment in gaseous diffusion plants is 50 times as high as that in
centrifuge plants (see subsection 2.16.3 below).
Some advanced technologies for electricity generation, such as NG combined-cycle (NGCC)
gas turbine for NG power plants and integrated gasification combined-cycle (IGCC) for coal
power plants, could increase their shares of electricity generation over time. The time-series
tables for the default shares of these advanced technologies used for NG power plants and
coal power plants in GREET are shown in Table 2.6.
32
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Table 2.4. Default electricity generation mix
U.S. mix: Average
Year
1990
1995
2000
2005
2010
2015
2020
Residual Oil
4.2%
2.2%
2.9%
1.7%
1.7%
2.5%
1.9%
Power
NG
12.3%
14.8%
15.8%
18.4%
20.6%
22.7%
24.2%
Plant types
Coal
52.5%
51.0%
51.7%
50.3%
50.2%
48.6%
49.2%
Nuclear
19.0%
20.1%
19.8%
19.4%
17.7%
16.6%
15.4%
Others
12.1%
11.9%
9.7%
10.2%
9.9%
9.6%
9.3%
U.S. mix: Marginal
Year
1990
1995
2000
2005
2010
2015
2020
Residual Oil
4.2%
2.2%
2.9%
1.7%
1.7%
2.5%
1.9%
Power
NG
12.3%
14.8%
15.8%
18.4%
20.6%
22.7%
24.2%
Plant types
Coal
52.5%
51.0%
51.7%
50.3%
50.2%
48.6%
49.2%
Nuclear
19.0%
20.1%
19.8%
19.4%
17.7%
16.6%
15.4%
Others
12.1%
11.9%
9.7%
10.2%
9.9%
9.6%
9.3%
NEU.S. mix: Average
Year
1990
1995
2000
2005
2010
2015
2020
Residual Oil
15.1%
5.6%
7.4%
5.8%
5.7%
7.7%
6.2%
Power
NG
8.6%
18.9%
15.2%
19.5%
22.6%
24.7%
27.9%
Plant types
Coal
37.2%
35.6%
35.9%
31.0%
31.1%
29.3%
29.2%
Nuclear
28.7%
30.2%
32.0%
31.9%
29.2%
27.2%
25.8%
Others
10.4%
9.7%
9.5%
11.8%
11.3%
11.1%
10.9%
NE U.S. mix: Marginal
Year
1990
1995
2000
2005
2010
2015
2020
Residual Oil
15.1%
5.6%
7.4%
5.8%
5.7%
7.7%
6.2%
Power
NG
8.6%
18.9%
15.2%
19.5%
22.6%
24.7%
27.9%
Plant types
Coal
37.2%
35.6%
35.9%
31.0%
31.1%
29.3%
29.2%
Nuclear
28.7%
30.2%
32.0%
31.9%
29.2%
27.2%
25.8%
Others
10.4%
9.7%
9.5%
11.8%
11.3%
11.1%
10.9%
33
-------
Table 2.4. Default electricity generation mix (Cont'd)
California mix: Average
Voar
i ear
1990
1995
2000
2005
2010
2015
2020
Residual Oil
2.3%
0.2%
0.2%
0.8%
0.5%
0.6%
0.4%
Power
NG
40.0%
37.5%
42.1%
40.7%
38.4%
34.5%
32.1%
Plant types
Coal
11.2%
8.6%
14.5%
14.7%
19.1%
24.9%
27.5%
Nuclear
19.2%
17.3%
17.1%
18.1%
16.2%
14.7%
13.4%
Others
27.3%
36.3%
26.0%
25.8%
25.7%
25.4%
26.7%
California mix: Marginal
Year
1990
1995
2000
2005
2010
2015
2020
Residual Oil
2.3%
0.2%
0.2%
0.8%
0.5%
0.6%
0.4%
Power
NG
40.0%
37.5%
42.1%
40.7%
38.4%
34.5%
32.1%
Plant types
Coal
11.2%
8.6%
14.5%
14.7%
19.1%
24.9%
27.5%
Nuclear
19.2%
17.3%
17.1%
18.1%
16.2%
14.7%
13.4%
Others
27.3%
36.3%
26.0%
25.8%
25.7%
25.4%
26.7%
Table 2.5. GREET default shares of gaseous diffusion and centrifuge technologies for
uranium enrichment
Year
1990
1995
2000
2005
2010
2015
2020
LWR: electric
generation
Gaseous
,.ff . Centrifuge
diffusion
93% 7%
87% 13%
57% 43%
30% 70%
25% 75%
15% 85%
10% 90%
HTGR: electric
generation
Gaseous
,.ff . Centrifuge
diffusion
93% 7%
87% 13%
57% 43%
30% 70%
25% 75%
15% 85%
10% 90%
34
-------
Table 2.6. Default shares of advanced power plant technologies
Year
1990
1995
2000
2005
2010
2015
2020
NGCC share of total NG
power plant capacity
10.0%
15.0%
20.0%
25.0%
30.0%
35.0%
35.0%
Advanced coal technology share of total
coal power plant capacity
0.0%
5.0%
5.0%
10.0%
15.0%
15.0%
15.0%
2.7 Key simulation options for biodiesel production pathway
Methyl or ethyl esters, produced from vegetable oils or animal fats, are commonly called
biodiesel. In the United States, biodiesel is mainly produced from soybeans. The GREET
model includes the soybean-to-biodiesel fuel cycle.
In addition to the biodiesel fuel, Soybean-to-biodiesel fuel cycle produces co-products such
as soy meal and glycerine. GREET allocates emissions and energy use charge for each
process between the biodiesel and its co-products. The default energy and emission
allocations for biodiesel in the soybean farming, soy oil extraction, and soy oil
transesterification processes are 33.6%, 33.6% and 70.1%, respectively, based on market
value-based method as shown in Figure 2.13.
Si. Pathways Options for Base Year: 2010
Petroleum
Natural Gas
LPG
Ethanol
Electricity
Energy and Emission Allocations
Soy Diesel
Soybean Farming: I 62.1
Soy Oil Extraction: 62.1
Soy Oil Transesterification: j 79.6
« Back
Continue »
Figure 2.13. Biodiesel production pathway options
35
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2.8 Key simulation options for alternative fuel blends
In GREETGUI, the user can specify the volumetric shares of alternative fuels for blending
with gasoline or diesel (see Figure 2.14). The default blending levels of alternative fuels with
gasoline or diesel are listed in Table 2.7. The user can change the blending levels of
methanol, ethanol (high-level blending), Fischer-Tropsch diesel or biodiesel in GREETGUI.
Since the default blending levels are passed to GREETGUI from MOVES, the user is
cautioned to make any changes in GREETGUI to be consistent with that in MOVES.
Ethanol-gasoline blends have two blending levels in GREET: low-level blend with ethanol
volumetric content of 5% - 15% (the default value set in MOVES is 10%) and high-level
blend with ethanol volumetric content of 15% - 90% (the default value set in GREET is
85%). If user specifies a different blend level (e.g., 40%) for the high-level blend, the user
should revise the vehicle fuel economy and emission factors in MOVES to reflect the new
blend level.
The GREET user can select either conventional gasoline, reformulated gasoline, or a
combination of these two fuels, with specific market share of each, for blending with
methanol and ethanol. GREET assumes that ethanol is blended with CG for low-level blends
(similar to wintertime oxygenated fuel) and with market share-weighted combination of CG
and RFG for high-level blends. Note that ethanol used as RFG oxygenate is simulated
separately under the RFG simulation options, not as ethanol blend simulation option. Similar
to ethanol high-level blends, GREET assumes that methanol is blended with market
share-weighted combination of CG and RFG.
36
-------
E:] Simulation Options for Alternative Fuel Blends x|
NOTE: Shares used here should be consistent with the shares selected in MOVES
Share of Alternative Fuels for Blending by Volume:
Methanol (for Blending with Gasoline): FTB (for Blending with Diesel):
MeOH: | 851)%
Ethanol (for Blending with Gasoline):
EtQH (Low-LevelE10):
EtQH (High-level):
FTD:| 100.0%
BD (for Blending with Diesel):
BD: I 200%
85.0%
Methanol
CG
~
Ethanol (Low-Level Blend)
RFG CG
Ethanol (High-Level Blend)
Biodiesel
« Back
! Continue » 1
Figure 2.14. Simulation options for alternative fuel blends
The GREET user can select either conventional diesel, low-sulfur diesel, or a combination of
these two fuels, with specific market share of each, for blending with Fischer-Tropsch diesel
and biodiesel. GREETGUI currently assumes that FT diesel and biodiesel to be blended with
market share-weighted combination of conventional diesel and low-sulfur diesel.
Table 2.7. Default shares of alternative fuels for blending with gasoline or diesel
Alternative fuels Blending share (vol, %)
Methanol
Ethanol (low-level, E10)
Ethanol (high-level)
Fischer-Tropsch diesel
Biodiesel
85%
10%
85%
100%
20%
37
-------
3. Key Parametric Assumptions
3.1 Key parametric assumptions for the production of petroleum-based fuels
Energy efficiencies of crude oil recovery and refining process to produce various fuels are
considered key parameters, which the user can specify in GREETGUI, see Figure 3.1. Since
these parameters may change over time, time-series tables were developed in GREET for
energy efficiencies of petroleum-related processes, Table 3.1.
Si. Fuel Production Assumptions -Year: 2010
Petroleum | Natural Gas j Ethanol | Electricity]
Items
Crude Recovery Efficiency (%)
CG Refining Efficiency (%)
FRFG Refining Efficiency (%)
CARFG Refining Efficiency (%)
CD Refining Efficiency (%)
LPG Refining Efficiency (%)
Assumptions
97.7%
86.0%
85.5%
85.5%
89.0%
93.5%
Continue »
Figure 3.1. Key parametric assumptions for production of petroleum-based fuels
Table 3.1. Default energy efficiencies for petroleum-related processes
Year
1990
1995
2000
2005
2010
2015
2020
Energy efficiency, %
Crude
Recovery
97.7
97.7
97.7
97.7
97.7
97.7
97.7
CG
Refining
86.5
86.5
86.0
86.0
86.0
86.0
85.5
RFG
Refining
86.0
86.0
85.5
85.5
85.5
85.5
85.0
CARFG
Refining
86.0
86.0
85.5
85.5
85.5
85.5
85.0
CD
Refining
89.5
89.5
89.5
89.5
89.0
89.0
89.0
LSD
Refining
87.0
87.0
87.0
87.0
87.0
87.0
87.0
LPG
Refining
93.5
93.5
93.5
93.5
93.5
93.5
93.5
38
-------
3.2 Key parametric assumptions for the production of NG-based fuels
Energy efficiencies associated with NG recovery and processing, NG-based fuels production,
and steam credit are key parameters, which the user can specify in GREETGUI, Figure 3.2.
Since some of these parameters may change over time, time-series tables were developed in
GREET for energy efficiencies and steam credits of NG-related processes, which are
discussed below in details.
3.2.1 Key fuel combustion technologies
Energy efficiency of steam boilers is a key parameter for steam co-generation in many fuel
production facilities. This parameter is used to calculate the steam export credit. The default
value in GREET is 80%.
The efficiency of electricity generated from low-quality steam is a key parameter for
electricity co-generation in some fuel production facilities. This parameter is used to calculate
the electricity export credit in those facilities. The GREET default efficiency for electricity
cogeneration is 30%. The low efficiency is due to the low-quality steam used for electricity
generation.
Fuel Production Assumptions -Year: 2010
Petroleum [.Natural Gas j| Ethanol | Electricity)
2
-------
3.2.2 NG recovery and processing
The default energy efficiencies for NG recovery and processing in GREET are shown in
Table 3.2.
3.2.3 NG compression and liquefaction
The default energy efficiencies for NG compression and liquefaction in GREET are shown in
Table 3.3. When NNA NG or NNA FG is selected as the feed stock source for CNG
production, liquefied natural gas (LNG) is assumed to be an intermediate fuel to bring NNA
NG or FG to North America, which is accounted for in the simulation of these specific
pathways.
Table 3.2. Default energy efficiencies for NG recovery and processing
Year
1990
1995
2000
2005
2010
2015
2020
Feedstock
Recovery
97.5%
97.5%
97.5%
97.5%
97.5%
97.5%
97.5%
NANG
Processing
97.5%
97.5%
97.5%
97.5%
97.5%
97.5%
97.5%
Feedstock:
Recovery
97.5%
97.5%
97.5%
97.5%
97.5%
97.5%
97.5%
NNANG
Processing
97.5%
97.5%
97.5%
97.5%
97.5%
97.5%
97.5%
Feedstock:
Recovery
97.0%
97.0%
97.0%
97.0%
97.0%
97.0%
97.0%
NNAFG
Processing
97.0%
97.0%
97.0%
97.0%
97.0%
97.0%
97.0%
Table 3.3. Default energy efficiencies for NG compression and liquefaction
Year
1990
1995
2000
2005
2010
2015
2020
Compression
NG
compressor
93.0%
93.0%
93.0%
93.0%
93.0%
93.0%
93.0%
Electric
compressor
97.0%
97.0%
97.0%
97.0%
97.0%
97.0%
97.0%
NANG
88.5%
89.0%
90.0%
90.0%
90.3%
91.0%
91.5%
Liquefaction
NNANG
88.5%
89.0%
90.0%
90.0%
90.3%
91.0%
91.5%
NNAFG
88.5%
89.0%
90.0%
90.0%
90.3%
91.0%
91.5%
3.2.4 NG-based LPG production
The default energy efficiencies for LPG production from NG are shown in Table 3.4.
40
-------
Table 3.4. Default energy efficiencies for NG-based LPG production
Year
1990
1995
2000
2005
2010
2015
2020
LPG production: NG as
96.5%
96.5%
96.5%
96.5%
96.5%
96.5%
96.5%
feedstock
3.2.5 Methanol production
The default energy efficiencies and steam credit for methanol production in GREET are
shown in Tables 3.5 and 3.6, respectively. Electricity export credit is calculated from the
amount of steam credit in Table 3.6 and the electricity cogeneration efficiency (GREET
default value is 30%).
Table 3.5. Default energy efficiencies for methanol production
Year
1990
1995
2000
2005
2010
2015
2020
Feedstock
no steam
orkWh
export
65.0%
66.0%
67.0%
67.5%
67.8%
70.0%
71.0%
:NANG
with steam
orkWh
export
62.0%
62.5%
63.0%
63.5%
64.0%
67.0%
69.0%
Feedstock
no steam
orkWh
export
65.0%
66.0%
67.0%
67.5%
67.8%
70.0%
71.0%
NNANG
with steam or
kWh export
62.0%
62.5%
63.0%
63.5%
64.0%
67.0%
69.0%
Feedstock
no steam
orkWh
export
64.5%
65.5%
66.5%
67.0%
67.5%
69.5%
70.5%
:NNAFG
with steam or
kWh export
61.5%
62.0%
62.5%
63.0%
63.5%
66.5%
68.5%
Table 3.6. Default steam credit (Btu/mmBtu of fuel produced) for methanol
Year
1990
1995
2000
2005
2010
2015
2020
Feedstock: NA NG
77853
77853
77853
77853
77853
77853
77853
Feedstock: NNA NG
77853
77853
77853
77853
77853
77853
77853
Feedstock: NNA FG
77853
77853
77853
77853
77853
77853
77853
41
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3.2.6 FTD production
The default energy efficiencies, steam credit and carbon efficiencies for FTD production in
GREET are shown in Tables 3.7, 3.8 and 3.9, respectively. Electricity export credit is
calculated from the amount of steam credit in Table 3.8, and the electricity cogeneration
efficiency (GREET default value is 30%).
3.3 Key parametric assumptions for ethanol production
Energy use in corn/biomass farming and ethanol production, and CC>2 emissions due to land
use change by corn/biomass farming are key parameters, which the user can specify in
GREET, see Figure 3.3. Depending on the selection of different market shares of ethanol
feedstock sources and/or different plant design types, the default parametric assumptions
shown in Figure 3.3 could change. Since these parameters may change over time, time-series
tables were developed in GREET for the default assumptions in each ethanol-related process
as shown in Tables 3.10, 3.11 and 3.12, respectively.
Table 3.7. Default energy efficiencies for FTD production
Year
1990
1995
2000
2005
2010
2015
2020
Feedstock
no steam
orkWh
export
61.0%
61.5%
62.0%
62.5%
63.0%
64.0%
65.0%
:NANG
with steam
orkWh
export
51.0%
52.0%
53.0%
54.0%
55.0%
57.0%
58.0%
Feedstock
no steam
orkWh
export
61.0%
61.5%
62.0%
62.5%
63.0%
64.0%
65.0%
NNANG
with steam or
kWh export
51.0%
52.0%
53.0%
54.0%
55.0%
57.0%
58.0%
Feedstock
no steam
orkWh
export
60.5%
61.0%
61.5%
62.0%
62.5%
63.5%
64.5%
:NNAFG
with steam or
kWh export
50.5%
51.5%
52.5%
53.5%
54.5%
56.5%
57.5%
Table 3.8. Default steam credit (Btu/mmBtu of fuel produced) for FTD production
Year
1990
1995
2000
2005
2010
2015
2020
Feedstock: NA NG
202000
202000
202000
202000
202000
202000
202000
Feedstock: NNA NG
202000
202000
202000
202000
202000
202000
202000
Feedstock: NNA FG
202000
202000
202000
202000
202000
202000
202000
42
-------
Table 3.9. Default carbon efficiencies for FTD production
Year
1990
1995
2000
2005
2010
2015
2020
Feedstock
no steam
orkWh
export
78.0%
78.0%
78.0%
79.0%
80.0%
80.5%
81.0%
:NANG
with steam
orkWh
export
78.0%
78.0%
78.0%
79.0%
80.0%
80.5%
81.0%
Feedstock
no steam
orkWh
export
78.0%
78.0%
78.0%
79.0%
80.0%
80.5%
81.0%
NNANG
with steam or
kWh export
78.0%
78.0%
78.0%
79.0%
80.0%
80.5%
81.0%
Feedstock
no steam
orkWh
export
78.0%
78.0%
78.0%
79.0%
80.0%
80.5%
81.0%
:NNAFG
with steam or
kWh export
78.0%
78.0%
78.0%
79.0%
80.0%
80.5%
81.0%
Petroleum | Natural Gas LithanoJJ
Electricity]
Items
C02 Emissions from Landuse Change by Corn Farming (g/bushel)
Corn Farming Energy Use (Eltu/bushel)
Ethanol Production Energy Use:Dry Mill (FJtu/gallon)
Ethanol Production Energy Use:Wet Mill (Btu/gallon)
Assumptions
195.0
23,000
36,000
46,000
x|
Continue »
Figure 3.3. Key parametric assumptions for production of ethanol fuel
Table 3.10. Default corn/biomass farming energy use
Year
1990
1995
2000
2005
2010
2015
2020
Corn farming,
Btu/bushel
23600
23500
23288
23000
22500
22500
22500
Woody biomass
farming, Btu/dry ton
234770
234770
234770
234770
234770
234770
234770
Herbaceous biomass
farming, Btu/dry ton
217230
217230
217230
217230
217230
217230
217230
43
-------
Table 3.11. Default energy use, yield or kWh co-production for ethanol production
Year
1990
1995
2000
2005
2010
2015
2020
Energy use of
corn-ethanol
production, Btu/gal
JJry Wet
milling milling
40000 55000
39000 50000
37000 46200
36500 46000
36000 45950
36000 45950
36000 45950
Woody biomass-ethanol
production
Yield: Electricity
gal/dry co-production:
ton kWh/gal
82.0 -1.150
83.0 -1.150
84.0 -1.150
85.0 -1.150
87.0 -1.145
87.0 -1.145
87.0 -1.145
Herbaceous
biomass-ethanol production
Yield:
gal/dry
ton
85.0
87.0
89.0
90.0
91.5
91.5
91.5
Electricity
co-production:
kWh/gal
-0.600
-0.600
-0.600
-0.600
-0.572
-0.572
-0.572
Note: negative values imply credit.
Table 3.12. Default COi emissions due to land use change by corn/biomass farming
Year
1990
1995
2000
2005
2010
2015
2020
Corn farming, g/bushel
195.0
195.0
195.0
195.0
195.0
195.0
195.0
Woody biomass farming,
g/dry ton
-112,500
-112,500
-112,500
-112,500
-112,500
-112,500
-112,500
Herbaceous biomass
farming, g/dry ton
-48,500
-48,500
-48,500
-48,500
-48,500
-48,500
-48,500
Note: positive values imply emissions, and negative values imply sequestration.
3.4 Key parametric assumptions for electricity generation
Efficiency of electricity generation at various types of power plant, and electricity
transmission and distribution losses are key parameters, which the user can specify in the
GREET model (see Figure 3.4). The user can also specify other key parameters for
nuclear-based electricity generation processes. Since these parameters may change over time,
time-series tables were built in GREET for each electricity generation process, which are
discussed in the following sections.
44
-------
ii. Fuel Production Assumptions -Year: 2010
Petroleum ] Natural Gas | Ethanol Lil.sptncityjl
Items
Residual Oil Utility Boiler Efficiency (%)
NG Utility Boiler Efficiency (%)
NG Simple Cycle Turbine Efficiency (%)
NG Combined Cycle Turbine Efficiency (%)
Coal Utility Boiler Efficiency (%)
Advanced Coal Technology for Power Generation (%)
Electricity Transmission and Distribution Loss (%)
Energy intensity in HTGR reactors (MWh/g of U-235)
Energy intensity in LWR reactors (MWh/g of U-235)
Electricity Use of Uranium Enrichment (kWh/SWU):
Gaseous Diffusion Plants for LWR electricity generation
Electricity Use of Uranium Enrichment (kWh/SWU):
Centrifuge Plants for LWR electricity generation
Electricity Use of Uranium Enrichment (kWh/SWU):
Gaseous Diffusion Plants for HTGR electricity generation
Electricity Use of Uranium Enrichment (kWh/SWU):
Centrifuge Plants for HTGR electricity generation
Assumptions
34.8%
34.8%
33.1%
53.0%
34.1%
47.0%
8.0%
8.704
6.926
2,400
50.00
2,400
50.00
Continue »
x|
Figure 3.4. Key parametric assumptions for production of electricity
3.4.1 Electricity generation efficiencies
The default electricity generation efficiencies in GREET for different types of power plant
are shown in the Table 3.13.
Table 3.13. Default electricity generation efficiencies of various types of power plant
Year
1990
1995
2000
2005
2010
2015
2020
Residual
oil
Utility
boiler
31.0%
32.0%
33.0%
34.0%
34.8%
34.8%
34.8%
NG
Utility
boiler
31.0%
32.0%
33.0%
34.0%
34.8%
34.8%
34.8%
Simple cycle
turbine
31.0%
32.0%
33.0%
33.0%
33.1%
33.1%
33.5%
Combined
cycle turbine
45.0%
45.0%
45.0%
47.0%
53.0%
53.0%
55.0%
Coal
Utility
boiler
32.0%
33.0%
33.5%
34.0%
34.1%
34.1%
34.4%
Advanced coal
combined cycle
turbine
40.0%
40.0%
43.0%
45.0%
47.0%
47.0%
50.0%
3.4.2 Electricity transmission and distribution loss
The default electricity transmission and distribution loss in GREET is 8%.
45
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3.4.3 Key parameters of nuclear-related electricity generation processes
The GREET defaults for electricity generation intensity of nuclear reactors and electricity use
in uranium enrichment process are shown in Table 3.14.
Table 3.14. Default parameters of nuclear-related electricity generation processes
Year
1990
1995
2000
2005
2010
2015
2020
Electricity generation
intensity: MWh/g of
235U
LWR HTGR
6.926 8.704
6.926 8.704
6.926 8.704
6.926 8.704
6.926 8.704
6.926 8.704
6.926 8.704
Electricity use of uranium enrichment: kWh/SWUa
Gaseous diffusion plant
LWR HTGR
2400 2400
2400 2400
2400 2400
2400 2400
2400 2400
2400 2400
2400 2400
Centrifuge plant
LWR HTGR
50 50
50 50
50 50
50 50
50 50
50 50
50 50
a: SWU: separative work units.
3.5 Key parameters for fuel transportation, distribution and storage
In GREET, transportation-related activities are simulated by using input parameters such as
transportation modes, transportation distances and energy use intensities (in Btu/ton-mi) for
various modes of transportation. These parameters, which can be specified by the user as
shown in Figure 3.5, are discussed in the following subsections.
3.5.1 Transportation mode and distance
Transportation modes for transportation fuels in GREET include the following: 1) ocean
tankers for crude oil, gasoline, diesel, LPG, LNG, methanol and FTD; 2) barges for crude oil,
gasoline, diesel, LPG, LNG, methanol, FTD, ethanol, and biodiesel; 3) pipelines for crude
oil, gasoline, diesel, LPG, FTD, biodiesel, and NG; 4) rails for gasoline, diesel, LPG, LNG,
methanol, ethanol, FTD, and biodiesel; and 5) trucks for delivering liquid fuels from bulk
terminals to refueling stations. The user can specify shares of transportation mode, and
transportation distance for each mode as shown in Figure 3.5. The default estimates of these
parameters in GREET are shown in Tables 3.15 through 3.17. Note that the total percentage
of all transportation modes may exceed 100% for some fuels because more than one mode
may be involved for transporting the fuel.
46
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», Feedstock and Fuel Transportation Assumptions
Transportation Modes | Ocean Tanker Size ]
Fuel/Feedstock
Petroleum
Crude for U.S. Average
CG
RFG
CARFG
CD
Mode Share
Distance (miles)
Mode Share
Distance (miles)
Mode Share
Distance (miles)
Mode Share
Distance (miles)
Mode Share
Distance (miles)
NG-Based Fuel
CNG: NA
MeOH: NNA-NG
FTD: NNA-NG
Mode Share
Distance (miles)
Mode Share
Distance (miles)
Mode Share
Feedstock NG
Transmission
Pipeline
Transportation
Ocean
Tanker
57.0%
5,080
20.0%
1,700
20.0%
1,700
0.0%
3,900
16.0%
1,450
100.0%
750
100.0%
50.0
3,000
100.0%
r rtnrt
Barge
Pipeline
Petroleum
1.0% 100.0%
500
4.0%
520
4.0%
520
0.0%
200
750
73.0%
400
73.0%
400
95.0%
150
6.0% 75.0%
520 400
NG-Based Fuel
40.0% 0.0%
520
33.0%
600
60.0%
Rail
0.0%
800
7.0%
800
7.0%
800
5.0%
250
7.0%
800
40.0%
700
7.0%
Truck
Distribution
Truck
0.0%
30.0
10.0%
BO.O
30.0
30.0
30.0
30.0
30.0
« Back
3
d
i Continue » 1
Figure 3.5. Feedstock and fuels transportation modes and distances
fable 3.15. Default Transportation Modes and Distance for Fuels from Production Sites
to Bulk Terminals
Crude oil:
U.S. use
Crude oil:
CAuse
CG
RFG
CARFG
CD
CACD
LSD
CALSD
Mode share
Distance, mile
Mode share
Distance, mile
Mode share
Distance, mile
Mode share
Distance, mile
Mode share
Distance, mile
Mode share
Distance, mile
Mode share
Distance, mile
Mode share
Distance, mile
Mode share
Distance, mile
Ocean
tanker
57%
5080
58%
3900
20%
1700
20%
1700
0%
3900
16%
1450
16%
3900
16%
1450
16%
3900
Barge
1%
500
0%
200
4%
520
4%
520
0%
200
6%
520
6%
200
6%
520
6%
200
Pipeline
100%
750
42%
150
73%
400
73%
400
95%
150
75%
400
75%
150
75%
400
75%
150
Rail
0%
800
0%
200
7%
800
7%
800
5%
250
7%
800
7%
300
7%
800
7%
300
Truck
0%
30
47
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LPG: NA
NG
LPG: NNA
NG
LNG: NNA
NG
LNG: NNA
FG
MeOH: NA
NG
MeOH:
NNANG
MeOH:
NNAFG
MeOH: LG
FTD: NA
NG
FTD:
NNANG
FTD:
NNAFG
Biodiesel
EtOH
Mode share
Distance, mile
Mode share
Distance, mile
Mode share
Distance, mile
Mode share
Distance, mile
Mode share
Distance, mile
Mode share
Distance, mile
Mode share
Distance, mile
Mode share
Distance, mile
Mode share
Distance, mile
Mode share
Distance, mile
Mode share
Distance, mile
Mode share
Distance, mile
Mode share
Distance, mile
Ocean
tanker
0%
5200
100%
5200
100%
5000
100%
5900
0%
0
100%
3000
100%
5900
0%
0
0%
0
100%
5000
100%
5900
Barge
6%
520
6%
520
0%
520
0%
520
40%
520
40%
520
40%
520
40%
0
33%
520
33%
520
33%
520
8%
520
40%
520
Pipeline
64%
400
60%
400
0%
600
0%
600
0%
600
0%
0
60%
400
60%
400
60%
400
63%
400
0%
600
Rail
34%
800
34%
800
0%
800
0%
800
40%
700
40%
700
40%
700
40%
0
7%
800
7%
800
7%
800
29%
800
40%
800
Truck
10%
80
10%
80
10%
80
10%
0
20%
80
Table 3.16. Default distance from NG fields to NG-based production plants
NG usage
Distance (mile)
LNG Plant
LPG plant
Methanol plant
FTD Plant
50
50
50
50
48
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Table 3.17. Default distance for fuel distribution from bulk terminals to refueling
stations
Crude oil: CAuse
CG
RFG
CARFG
CD
CACD
LSD
CALSD
LPG
LNG
MeOH
FTD
Biodiesel
EtOH
Distance (mile)
30
30
30
30
30
30
30
30
30
30
30
30
30
30
3.5.2 LNG boil-off
The GREET user can specify the boiler-off rate, duration of storage and recovery rate of
boil-off gas for LNG fuel as shown in Figure 3.6. The default values of these parameters in
GREET are listed in Table 3.18.
Bj Feedstock and Fuel Transportation Assumptions
Transportation Modes Boiloff Ocean Tanker Size |
Production
Site Storage
Transportation
Bulk Terminal
Storage
Distribution
Refueling
Station (for
Central Plant
Production)
Refueling
Station (for
Station
Production)
Fuel Loss Rate: % loss per day
LNG
Storage Duration: Days
_NG (final transportation fuel)
-NG (intermediate from HNA HG)
Recovery Rale
LNG
Fuel Loss Rate: % loss per day
0.1% 0.1% 0.1% 0.1% 0.1%
Storage Duration: Days
5 1 5 0.1 3
5 11 5 0.1 3
Recovery Rate
80.0% 80.0% 80.0% 80.0% 80.0%
« flack
Continue » |
Figure 3.6. LNG boil-off data
49
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Table 3.18. Default parameters for LNG boil-off process
LNG
LNG:
NNANG
LNG:
NNAFG
Storage at
production
plant
0.1%
Plant to
bulk
terminal
0.1%
Bulk Bulk
terminal terminal to
storage stations
Boil-off rate: % loss
0.1% 0.1%
Station storage
for central
plant pathway
per day
0.1%
Station storage
for refueling
station
pathway
Duration of storage or transit: days
5
5
lla
13a
5 0.1
5 0.1
3
3
LNG
80%
Recovery rate for boil-off gas
80% 80% 80% 80%
Calculated based on transportation mode share and distance specified for LNG in GREET and cannot be
changed by the user
The boil-off gas from bulk terminals and refueling stations can be recovered
3.5.3 Cargo payload of ocean tanker
The user can specify cargo payload of ocean tanker for some transportation fuels as shown in
Figure 3.9. The default values for cargo payload of ocean tankers are listed in Table 3.39.
4. Feedstock and Fuel Transportation Assumptions
T ransportation M odes 0 cean T anker S ize
Items
Crude Oil
Gasoline
Diesel
LPG
Methanol
FTD
Ocean Tanker Size (tons)
1,143,000
150,000
150,000
80,000
150,000
150,000
Back
Continue »
Figure 3.7. Ocean tanker size
50
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Table 3.19. Default cargo payload of ocean tanker for fuels
Fuel
Crude oil
Gasoline
Diesel
LPG
LNG
Methanol
FTD
Payload (tons)
1,143,000
150,000
150,000
80,000
58,000
150,000
150,000
51
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4. GREET Model Structure
The current version of the GREET spreadsheet model (version 1.6) consists of 23 Excel
sheets; each of which is briefly described below.
4.1 Overview
This sheet contains the GREET copyright statement. It presents a brief summary of each of
the worksheets in GREET and is intended to briefly introduce the functions of each sheet. It
is highly recommended that first-time GREET user reads this sheet before proceeding with
any GREET calculations.
4.2 Inputs
In this sheet, key control variables are presented for various scenarios to be simulated in
GREET and key parametric assumptions are specified for the simulation. GREETGUI mainly
interacts with this sheet to set the parameters of the fuel pathways to be simulated in GREET.
The cells colored in yellow and green are input cells and represent the key options and
parameters for simulation of different fuel cycles in GREET. The user can edit the yellow and
green cells to change the default simulation options or assumptions in these cells. The green
cells have probability distribution functions built into them for use with Crystal Ball,
commercial software developed by Decisioneering, Inc. The user can load the GREET model
into the Crystal Ball program to generate stochastic results rather than a point estimate of
energy use and emissions.
The cells without background color have formulas linked with other cells or with the
time-series (TS) tables in the following worksheets Fuel TS, Cars LDT1 _TS, LDT2 TS and
Fuel Specs. Detailed discussion of these sheets can be found in sections 4.4, 4.6, 4.7 and 4.8,
respectively. The user is strongly cautioned against any change to these cells, which could
result in broking formula links and failed or inaccurate simulation. To change any of the key
parameters associated with time-series (lookup) tables, e.g., conventional crude recovery
efficiency, the user may go to the appropriate time-series worksheet (e.g., Fuel TS in this
case) to change the entry of the corresponding yellow cell immediately above the time-series
table.
4.3 EF
In this sheet, emission factors (EFs) are presented for individual combustion technologies that
burn various fuels. These emission factors are used by other sheets of GREET to calculate
emissions associated with fuel combustion in various WTP stages.
52
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The first section of this sheet lists emission factors for combustion technologies applied to
stationary sources. Here all the cells have formula link with other cells or time-series tables in
ET_TS sheet (see detailed introduction of the EF_TS sheet in section 4.5). CC>2 emission
factors for all combustion fuels are calculated by using a carbon balance approach. SOx
emission factors for combustion technologies of all fuels except coal, biomass, crude and
residual oil are calculated by assuming that all sulfur contained in these process fuels is
converted into SC>2. The user is strongly cautioned against any change to these cells, which
could result in broking formula links and failed or inaccurate simulation. All other emission
factors are linked to time-series tables in the ET_TS sheet. For those emission factors linked
with time-series tables, e.g., VOC, CO, and CH/t, the user may go to the EF_TS sheet to make
any desired changes to the emission factors.
The second section in this sheet includes three tables. The first table lists emission changes of
alternative fuels relative to a baseline fuel for power units applied to transportation facilities
(such as ocean tankers, barges, locomotives, trucks, pipelines, etc.). The second table lists the
emission rates for different transportation modes and different fuels used for the trips from
the product origin to its destination. The third table lists the emission rates for different
transportation modes and different fuels used for the trips from product destinations back to
its origin (back-haul trips).
4.4 FuelsJTS
This sheet presents all of the key parametric assumptions for various fuel production
pathways. Since these parameters may change over time, lookup (time-series) tables were
developed for each parameter over a period from 1990 to 2020, in five-year intervals. These
parameters are separated into seven groups: 1) petroleum-related fuel production processes
(e.g., crude recovery efficiency, CG refining efficiency, etc.); 2) NG-related fuel production
processes (e.g., North American NG recovery efficiency, North American NG processing
efficiency, etc.); 3) ethanol production processes (e.g., corn farming energy use, ethanol yield
of woody biomass plant, etc.); 4) biodiesel production processes (e.g., soy bean farming
energy use, soy oil extraction energy use, etc.); 5) electricity generation processes (e.g.,
residual oil power plant energy conversion efficiency, NG combined-cycle turbine power
plant energy conversion efficiency, etc.); and 6) nuclear fuel production processes (e.g.,
electricity use of uranium enrichment using gaseous diffusion technology or centrifuge
technology, etc.). For any simulation year between those years listed in the tables, GREET
simply uses a linear interpolation algorithm to calculate the estimate for that particular year.
The cell immediately above the time-series table, which is colored in yellow, has been
interpolated from the time-series table and represents the value of the parameter
corresponding to the target year of simulation. The yellow cell above the time-series table
serves also as a user input cell. If the user adjusts of the yellow cell value, the entire
time-series table may be automatically adjusted by the same percentage, depending on the
53
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time-series simulation option selected by the user in section 2.3 of the Inputs sheet. Changes
made to the yellow cells immediately above the time-series tables in this worksheet are
automatically linked to the Inputs sheet.
4.5 EF TS
This sheet presents time-series tables for emission factors from combustion technologies
applied to stationary sources. VOC, CO, NOx, PMio, CH4, and N2O emissions from various
combustor types fueled with NG, residual oil, diesel, gasoline, crude oil, LPG, coal and
biomass may change over time, as well as SOx emissions from various combustor types
fueled with coal, biomass, crude and residual oil. Time-series tables for emission factors
associated with different WTP activities are created in this sheet have the same format and
functionality as those created in the FUELS_TS sheet, which are discussed above in section
4.4. Changes made to the yellow cells immediately above the time-series tables in this
worksheet are automatically linked to the EF sheet for emission calculations by GREET.
4.6 Car LDT1 TS
In this sheet, time-series tables of fuel economy and emission rates/changes associated with
vehicle operations are presented for passenger cars and light duty truck 1 (LDT1). This sheet
is constructed in two sections. The first section contains time-series tables of fuel economy
and emission rates for baseline vehicles fueled with gasoline or diesel. The emission factors
of exhausted VOC, evaporative VOC, CO, NOX, exhausted PMi0, tire and brake wearing
PMio, CH4 and N2O are included in each time-series table in this sheet. The second section
contains time-series tables for the changes of fuel economy and emissions of
alternative-fueled vehicles and advanced technology vehicles relative to the baseline gasoline
or diesel vehicles. The time-series tables in this sheet have the same format and functionality
as those created in the FUELS_TS sheet, which are discussed above in section 4.4. Changes
made to the yellow cells immediately above the time-series tables in this worksheet are
automatically linked to the Inputs sheet for calculations of energy use and emissions due to
vehicle operations. It should be noted that the fuel economy in GREET does not affect the
well-to-pump calculations, and therefore is not passed from GREET to MOVES in any way.
It remains, however, a feature in GREET life cycle analysis of transportation fuels, which
could be used separately in an independent GREET run.
4.7 LDT2 TS
This worksheet is similar to the CAR LDT1 TS worksheet in format and functionality.
However, the time-series tables of fuel economy and emission rates/changes associated with
vehicle operations are presented here for the light duty truck 2 (LDT2). Changes made to the
yellow cells immediately above the time-series tables in this worksheet are automatically
linked to the Inputs sheet for calculations of energy use and emissions due to vehicle
54
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operations. It should be noted that the fuel economy in GREET does not affect the
well-to-pump calculations, and therefore is not passed from GREET to MOVES in any way.
It remains, however, a feature in GREET life cycle analysis of transportation fuels, which
could be used separately in an independent GREET run.
4.8 Fuel Specs
This sheet includes specifications for individual fuels. Fuel specifications of interest to
GREET are lower and higher heating values, fuel density, carbon weight ratio, and sulfur
weight ratio. Probability distribution functions are built for most of the fuel specifications.
These cells are colored in green. The parametric values for these fuel specifications are used
to estimate the energy consumption and emissions, as well as conversions among mass,
volume, and energy contents.
This sheet also contains other conversion parameters such as the global warming potentials
(GWPs) for individual greenhouse gases (GHGs). These are used in GREET to convert
emissions of GHGs into CO2-equivalent emissions. The Fuel Specs sheet also contains the
carbon content in VOCs, CO, CFLi, and CO2, and the sulfur content in SO2. These are used
for carbon emission and SOX emission calculations throughout the GREET model.
Since sulfur contents in conventional gasoline, conventional diesel, and conventional
California diesel are expected to change over time, time-series tables are developed at the
bottom of this sheet for the sulfur content of these three fuels.
4.9 T&D
This sheet is developed for calculations of energy use and emissions for transportation and
distribution (T&D) of feedstock's and fuels. The results of this sheet — energy use (in Btu)
and emissions (in g/mmBtu) — are used in other sheets for calculations associated with
different fuel cycles.
4.10 Urban_Shares
In this sheet, a default splits between urban and non-urban areas for a given facility type are
provided to calculate the urban emissions of five criteria air pollutants (VOC, CO, NOx, SOx,
and PMio) for each WTP stage and vehicle operation within various fuel-vehicle systems in
the GREET model.
4.11 Petroleum
This sheet is used to calculate well-to-pump (WTP) energy use and emissions of
petroleum-based fuels. Eight petroleum-based fuels are included in GREET: conventional
55
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gasoline (CG), reformulated gasoline (RFG), California reformulated gasoline (CARFG),
conventional diesel (CD), low-sulfur diesel (LSD), liquefied petroleum gas (LPG), crude
naphtha, and residual oil. Although residual oil is not a vehicle fuel, it is included here to
calculate the energy use and emissions associated with producing different transportation
fuels and electricity.
This sheet also presents calculations for MTBE, ethyl tertiary butyl ether (ETBE), and
tertiary amyl methyl ether (TAME), which together with ethanol, can be used as oxygenates
in RFG and CARFG. Energy use and emissions for ethanol are calculated in a separate sheet
designed specifically for ethanol (EtOH sheet, section 4.15 below). Based on the oxygenate
types and Ch content specified in the Inputs sheet for RFG and CARFG, this portion of the
Petroleum sheet calculates the appropriate amount of the selected oxygenate. Energy use and
emissions associated with producing the selected oxygenate are carefully taken into account
for RFG and CARFG energy and emission calculations in GREET.
4.12 NG
This sheet presents calculations of energy use and emissions for natural gas (NG)-based
fuels: compressed natural gas (CNG), liquefied natural gas (LNG), LPG, methanol (MeOH),
dimethyl ether (DME), Fischer-Tropsch diesel (FTD), and Fischer-Tropsch naphtha (FTN).
GREET can simulate production of these fuels from North American natural gas, non-North
American natural gas, and non-North American flared gas. For the non-North America
sources, GREET assumes that non-North American natural gas and flared gas are converted
into LNG for transportation to North America, where the fuel is produced.
4.13 Ag_Inputs
This sheet presents calculations for agricultural chemicals (or agricultural inputs, Ag Inputs),
including synthetic fertilizers and pesticides, which are used for the farming of corn, biomass,
and soybeans. Corn is a feedstock for ethanol, biomass is a feedstock for ethanol, and
soybeans are a feedstock for biodiesel. Three fertilizers are included: nitrogen, phosphate,
and potash. Pesticides include herbicides and insecticides. This sheet includes calculations for
the manufacturing of the chemicals as well as the transportation of the chemicals from
manufacturing plants to farms.
4.14 EtOH
This sheet calculates energy use and emissions for fuel cycles that involve producing ethanol
(EtOH) from corn, woody biomass, and herbaceous biomass. The following stages are
included in this sheet: corn/biomass farming and transportation, corn/biomass ethanol
production, as well as the transportation, distribution and storage of the ethanol fuel. For
corn-based ethanol, the sheet includes both wet and dry milling plants. For each plant type,
56
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energy and emission credits for ethanol co-products can be estimated by using the
displacement or the market value methods. For ethanol production from woody and
herbaceous biomass, the energy and emission credits for the co-generated electricity in
cellulosic ethanol plants are estimated by using the displacement method.
4.15 E-D Additives
This sheet presents energy use and emission calculations for additives in ethanol-diesel fuel
(E-diesel or E-D). The following stages are included in this sheet: additives manufacture,
additives transportation and storage.
4.16 BD
This sheet calculates energy use and emissions associated with producing biodiesel (BD)
from soybeans. The sheet includes soybean farming and transportation, soyoil extraction, and
soyoil transesterification to biodiesel. Energy use and emissions are allocated between
biodiesel and by-products according to the market value method.
4.17 Coal
This sheet is to calculate energy use and emissions for coal mining, cleaning, and
transportation. The results are used in other fuel cycles in which coal is used as a process fuel
or as a feedstock. For example, in calculating the energy use and emissions associated with
electricity generation in coal-fired power plants, GREET takes into account energy use and
emissions in coal mining, cleaning, and transportation, all of which are calculated in this
sheet.
4.18 Uranium
This sheet is used to calculate energy use and emissions for uranium ore mining and milling,
uranium ore transportation, uranium fuel enrichment, uranium conversion, fabrication and
waste storage, and uranium fuel transportation. The results of this sheet are used in the
Electric sheet for calculating the energy use and emissions of nuclear electric power plants
using LWR or HTGR. Even though nuclear power plants have zero operational energy use
and emissions, the upstream processing and the transportation of uranium consume energy
and generate emissions.
4.19 LF Gas
This sheet presents energy use and emission calculations for the fuel cycle that consists of
producing methanol from landfill gases (LF_Gas). GREET assumes that without methanol
production, landfill gases would otherwise be flared. Flaring the gases generates a significant
57
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amount of emissions. The emissions offset by producing methanol are taken into account as
emission credits for methanol production. Emissions from methanol combustion are taken
into account during vehicle operation.
4.20 Electric
This sheet is used to calculate energy use and emissions associated with the generation of
electricity, which is used for the production of transportation fuels and for the operation of
electric vehicles and grid-connected HEVs. In this sheet, GREET can calculate emission
factors of electric power plants according to combustion emission factors incorporated in the
model or take emission factors directly from the user. Energy use and emissions during
processing and transportation of power plant fuels, as well as during power plant electricity
generation, are all accounted for in the GREET model. The results in this sheet are in Btu or
g/mmBtu of electricity available at the user's site. That is, electricity loss during transmission
and distribution of electricity from power plants to the user's site is account for in GREET. In
this sheet, a total of ten types of electricity for energy use and emission calculations needed
by other worksheets are simulated. These types include the electricity generated from oil
power plants, NG power plants, coal power plants, nuclear power plants (LWR or HTGR),
hydro power plants, NG combined-cycle turbine power plants, U.S average generation mix,
North-eastern U.S generation mix, California generation mix, or user defined generation mix.
4.21 Vehicles
The Vehicles sheet is designed to calculate energy use and emissions associated with vehicle
operations. This sheet is constructed in three sections. The first (Scenario Control) section,
includes methanol and ethanol flexible-fuel vehicles, vehicles with low-level ethanol blended
in gasoline, and dedicated methanol and ethanol vehicles. The user can specify the content of
methanol or ethanol in the fuel blends. For Fischer-Tropsch diesel and biodiesel blended with
diesel, the user can specify the content of Fischer-Tropsch diesel or biodiesel in the fuel
blends. For ethanol blended with diesel, the user can specify the content of ethanol and
additives in the fuel blends. Furthermore, the user can specify the market share of RFG out of
RFG and CG or the market share of LSD out of LSD and CD for these alternative fuel
blends. The split for vehicle miles traveled by vehicles powered with grid electricity and
onboard internal combustion engines (for grid-connected HEVs) is also presented in this
section.
The second section of the Vehicles sheet (Vehicle Fuel Economy and Emission Changes)
presents fuel economy and emission changes associated with alternative-fueled vehicles and
advanced technology vehicles relative to the baseline gasoline or diesel vehicles. All these
data on fuel economy and emission changes may change over time, and are linked with
time-series tables constructed in the Cars LDT1 TS and LDT2 TS sheets.
58
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The third section (Per-Mile Fuel Consumption and Emissions) in the Vehicles sheet
calculates energy use and emissions associated with vehicle operations for individual vehicle
types. The fuel economy and emissions of baseline gasoline and diesel vehicles are
established in this section.
4.22 Results
This sheet presents results for the complete fuel cycle. The sheet is constructed in three
sections. In the first section (Well-to-Pump Energy Use and Emissions), energy and emission
results from wells to refueling station pumps (in Btu or g/mmBtu of fuel available at fuel
pumps) are presented for each transportation fuel.
In the second section (Well-to-Wheels Energy Use and Emissions), fuel-cycle
(well-to-wheels) energy use and emissions for each vehicle type are calculated. For each
vehicle type, energy use and emissions are presented separately for three stages: feedstock
(including recovery, transportation, and storage), fuel (including production, transportation,
storage, and distribution), and vehicle operation. Shares of energy use and emissions for each
of the three stages are also presented in this section. Both urban emissions (emissions
occurring in urban areas) and total emissions (emissions occurring everywhere) for the five
criteria pollutants are calculated in this section.
In the third section (Well-to-Wheels Energy and Emission Changes) of this sheet, changes in
fuel-cycle energy use and emissions by individual alternative-fueled vehicle type/advanced
vehicle technology type are calculated. The changes by fuel/vehicle technologies are
calculated against gasoline vehicles fueled with CG and/or RFG.
Users can generate the results with probability distributions of WTP, WTW, and WTW
changes for the cells colored in blue. This can be achieved using the Crystal Ball software to
conduct stochastic simulations within the GREET model. Without Crystal Ball, users can
conduct only point estimates of energy use and emissions.
4.23 Graphs
This sheet graphically presents bar charts for the energy use and emissions shares of
feedstock, fuel, and vehicle operations, for each simulated fuel/vehicle type. Furthermore, it
shows energy use and emissions changes by individual vehicle technologies relative to the
baseline gasoline vehicles powered by conventional gasoline and/or reformulated gasoline.
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