Researchers at Argonne National Laboratory have released updates to two key tools for the analysis of advanced transportation technologies: GREET, used to assess greenhouse gases, regulated emissions and energy use in transportation; and AFLEET, used to calculate and compare the costs and environmental benefits of a broad range of alternative fuel technologies.
GREET. 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 GREET1 2017 version for fuel-cycle analysis and GREET2 2017 version for vehicle-cycle analysis. The 2017 release of the suite of GREET (Greenhouse gases, Regulated Emissions, and Energy use in Transportation) models and associated documentation includes the following expansions and updates:
Added plastic-to-fuel (PTF) pathway.
Added biomass-derived high octane gasoline via indirect liquefaction and renewable gasoline/diesel pathways from fast pyrolysis.
Added wood biomass biofuel production pathways, considering carbon temporal effects.
Added new pathways for corn kernel fiber ethanol.
Updated CCLUB to include added four land use change (LUC) cases and associated soil organic carbon change (SOC) updates related to soybean biodiesel pathways.
Updated the emission factors of criteria air pollutant (combustion and non-combustion emissions) for SMR hydrogen and petroleum fuels.
Added new pathways for by-product hydrogen produced from chlor-alkali processes.
Implemented new pathways for fuel cell electric medium- and heavy-duty vehicles powered by gaseous hydrogen.
Expanded the power sector in GREET with several natural gas and coal combined heat and power (CHP) and carbon capture and storage (CCS) technologies.
Updated the fuel economy and vehicle weights of light duty vehicles.
Added LCI data for the production of new and recycled cathode material for batteries of electric vehicles. Also updated energy and water consumption for lithium-ion battery manufacturing.
Developed distribution functions for water consumption factors of major processes in GREET.
Added production pathway of the low octane gasoline-like fuel (LOF) and corresponding vehicle technology of gasoline compression ignition (GCI) engines.
Updated methane leakage emissions for natural gas pathways.
Updated US electricity generation mix based on most recent Energy Information Administration (EIA)’s Annual Energy Outlook (AEO).
Updated the inventory and process data of soybean farming, soy oil extraction, and vegetable oil transesterification processes.
Updated the inventory data of tallow rendering and high free fatty acid (FFA) oil transesterification processes associated with tallow biodiesel pathway.
Updated energy consumption and material efficiency for steel and Aluminum stamping.
GREET includes more than 100 fuel pathways including petroleum fuels, natural gas fuels, biofuels, hydrogen and electricity produced from various energy feedstock sources.
GREET was developed as a multidimensional spreadsheet model in Microsoft Excel. This public domain model is available free of charge for anyone to use.
AFLEET. The AFLEET (Alternative Fuel Life-Cycle Environmental and Economic Transportation Tool) is suited to aid those who make purchasing decisions for fleets as they compare vehicle technologies for emission reductions and air quality gains. This new version adds the ability to look at air pollutant emissions from well-to-wheel as it lets users evaluate not just “at-the-tailpipe” air pollutants, but also those arising from fuel production.
The tool uses data from Argonne’s GREET fuel-cycle model to generate necessary well-to-wheels petroleum use and GHG emission co-efficients for key fuel production pathways and vehicle types. In addition, Environmental Protection Agency’s MOtor Vehicle Emission Simulator (MOVES) and certification data are used to estimate tailpipe air pollutant emissions. Various sources are used to provide default cost data, including the Clean Cities Alternative Fuel Price Report and American Recovery and Reinvestment Act awards.
Updates for 2017 include:
Added low-NOx engine option for CNG and LNG heavy-duty vehicles.
Added diesel in-use emissions multiplier sensitivity case.
Added well-to-pump air pollutants and vehicle cycle petroleum use, GHGs, and air pollutants.
Added renewable diesel vehicles.
Updated biofuel and RNG feedstocks.
Added Idle Reduction Calculator to estimate the idling petroleum use, emissions, and costs for light-duty and heavy-duty vehicles.