T1E provides the CI for an individual facility in a reduced file size. The inputs are limited to only those inputs applying to the individual facility, which reduces the potential for input error.

CA-GREET is a California-specific version of Argonne National Laboratory’s GREET life cycle model which is used to calculate GHG emissions under the LCFS. Life Cycle Associates developed the original model for the California Air Resources Board (ARB) based on GREET version 1.8b.

In early 2015, ARB re-adopted the LCFS and developed two new CA-GREET models for first and next generation fuels, referred to as “Tier 1,” and “Tier 2” fuels, respectively. (Earlier post.)

• CA-GREET 2.0 – Tier 1: For conventionally produced first-generation fuels (Starch- and sugar-based ethanol, biodiesel, renewable diesel, CNG, LNG, CARBOB, and ULSD)

• CA-GREET 2.0 – Tier 2: For next-generation fuels (Cellulosic alcohols, hydrogen, drop-in fuels, etc.)

(Fuels not included in the Tier 1 model are in the Tier 2 category.)

Key differences between CA_GREET and the default GREET model:

• CA_GREET is configured with criteria pollutant emission factors that reflect California emission standards and emission policies.

• CA_GREET has a regional lookup table with regional inputs that allows a user to select from eight regions in a pull-down menu, representing feedstock and fuel regions involved in the production of California fuels, and California-specific input parameters rather than US average parameters.

• CA_GREET includes new fuel pathways based on the existing GREET structure. The model is configured for CNG and LNG from dairy digester gas and landfill gas, respectively. The model is also configured for waste cooking oil and tallow pathways. The model is not populated with all of the inputs for numerous sub-pathways such as corn and sugar cane ethanol. Developing additional sub-pathway inputs still require user modifications.