This release of GREET1_2011 model includes the following major updates:

• New algae pathways to produce bio-oil, including the algae growth, dewatering and oil extraction stages. Developed a separate spreadsheet (linked to GREET) known as the algae process description (APD) with detailed assumptions of the key stages of the algae pathways.
• New pathways for bio-oil production from palm, rapeseed, jatropha and cemelina.
• New pathways for renewable gasoline and diesel production from pyrolysis of cellulosic biomass.
• New shale gas (SG) production pathway.
• New renewable natural gas (RNG) pathways from anaerobic digestion (AD) and conventional manure management.
• New jet fuel pathways, including operation of various classes of commercial aircrafts.
• New options to account for energy uses and emissions associated with the construction of petroleum and NG wells, and coal mines.
• New geothermal power plant cycle options to account for energy and emissions burdens associated with plant and equipment composition and onsite construction activities for three geothermal power plant technologies.
• Updated petroleum recovery and refining estimates.
• Updated farming assumptions for corn stover, forest residue, switchgrass, sugarcane and soybean.

For more details on updates in GREET 1 2011, please download and read the following document:

• Summary of Expansions and Revisions of the GREET 1 2011 Version (310 kB pdf)

Argonne National Laboratory and the Great Plains Institute worked together to produce the online versions of the Fleet Footprint Calculator and Travel Carbon Calculator.

The Fleet Footprint tool, available at energychoicemodel.com/fleetcalculator/, allows the user to:

• Calculate the petroleum and greenhouse gas footprint of your fleet
• Compare different alternative fuels and vehicle technologies for a future medium-duty, heavy-duty or off-road vehicle purchase

• Calculate the daily or annual impact of your travel
• Compare the automobile's footprint to other transportation modes
• View alternatives for reducing the impact on the environment

The latest version of our Fuel-Cycle model. This updates the previous revision in numerous places and integrates new pathways for fuel production.

The Vehicle-Cycle model calculates the life-cycle energy use and emissions for vehicle production.

The Travel Carbon Calculator can be used to estimate your travel carbon footprint and find potential ways to reduce it. It uses results from the GREET Fuel-Cycle model with fuel economy data from the EPA and statistics from the ORNL's Transportation Energy Data Book.

Travel Carbon Calculator (62 kB zip)
What's Your Carbon Footprint? (1.9 MB pdf)

The GREET Fleet Footprint Calculator was developed for Clean Cities stakeholders to estimate greenhouse gas emissions and petroleum use for medium- and heavy-duty vehicles.

GREET Fleet Footprint Calculator 1.1a (401 kB xls)
User Guide for the GREET Fleet Footprint Calculator 1.1 (64 kB pdf)

To fully evaluate energy and emission impacts of advanced vehicle technologies and new transportation fuels, the fuel cycle from wells to wheels and the vehicle cycle through material recovery and vehicle disposal need to be considered. Sponsored by the U.S. Department of Energy's Office of Energy Efficiency and Renewable Energy (EERE), Argonne has developed a full life-cycle model called GREET (Greenhouse gases, Regulated Emissions, and Energy use in Transportation). It allows researchers and analysts to evaluate various vehicle and fuel combinations on a full fuel-cycle/vehicle-cycle basis. The first version of GREET was released in 1996. Since then, Argonne has continued to update and expand the model. The most recent GREET versions are the GREET 1.8c.1 version for fuel-cycle analysis and GREET 2.7 version for vehicle-cycle analysis. GREET was developed as a multidimensional spreadsheet model in Microsoft Excel. This public domain model is available free of charge for anyone to use.

For a given vehicle and fuel system, GREET separately calculates the following:

• Consumption of total energy (energy in non-renewable and renewable sources), fossil fuels (petroleum, natural gas, and coal together), petroleum, coal and natural gas.
• Emissions of CO2-equivalent greenhouse gases - primarily carbon dioxide (CO2), methane (CH4), and nitrous oxide (N2O).
• Emissions of six criteria pollutants: volatile organic compounds (VOCs), carbon monoxide (CO), nitrogen oxide (NOx), particulate matter with size smaller than 10 micron (PM10), particulate matter with size smaller than 2.5 micron (PM2.5), and sulfur oxides (SOx).

GREET includes more than 100 fuel pathways including petroleum fuels, natural gas fuels, biofuels, hydrogen and electricity produced from various energy feedstock sources

GREET simulates the following three vehicle classes: :

• Passenger cars
• Light Duty Truck 1 ( gross weight < 6000 lb)
• Light Duty Truck 2 ( gross weight < 8500 lb)

GREET includes more than 80 vehicle/fuel systems covering the following vehicle technologies:

• Conventional spark-ignition engine vehicles
• Spark-Ignition, Direct-Injection Engine Vehicles
• Compression-Ignition, Direct-Injection Engine Vehicles
• Hybrid electric vehicles
  • Spark-ignition engines
  • Compression-ignition engines
• Plug-in hybrid electric vehicles
  • Spark-ignition engines
  • Compression-ignition engines
• Battery-powered electric vehicles
• Fuel-cell vehicles