What is Carbon Intensity?

Carbon Intensity (CI) is a measure of the amount of carbon dioxide (CO₂) emissions produced per unit of energy or fuel. It is typically expressed in grams of CO₂ per megajoule (g CO₂/MJ) or kilograms of CO₂ per megawatt-hour (kg CO₂/MWh). CI provides a way to compare the environmental impact of different energy sources or fuels by quantifying the amount of CO₂ released during their production and use. The CI score from a crop on ucrop.it uses the feedstock calculator with the GREET model

The GREET model

The GREET model (Greenhouse gases, Regulated Emissions, and Energy use in Technologies) is a tool developed by Argonne National Laboratory to analyze the environmental impacts of various energy systems and technologies. One of its key outputs is the Carbon Intensity (CI) score, which is crucial for understanding the lifecycle greenhouse gas emissions of different fuels and energy sources.

The GREET model’s CI score encompasses several stages and factors:

Feedstock Production and Transportation:

• Agriculture or Extraction: Includes emissions from cultivating biofuels (like corn or soy) or extracting fossil fuels.
• Transportation: Emissions from moving feedstock from production sites to processing facilities.

Fuel Production:

• Conversion Processes: Emissions from refining or processing feedstock into usable fuels. For instance, converting crude oil to gasoline or biomass to ethanol.
• Energy Use: The amount of energy consumed during processing, which can contribute to overall emissions depending on the energy source.

Fuel Distribution:

Transport to Market: Emissions from distributing the final fuel to refueling stations or end users.

Fuel Use:

Combustion or Use: Emissions from the actual use of the fuel, such as burning gasoline in an engine or using electricity generated from coal.

End-of-Life and Co-Products:

• Waste and By-products: Accounting for emissions from waste disposal or treatment of by-products.
• Co-Product Credits: Some processes generate useful co-products (like animal feed from biofuel production) that can offset the CI score by reducing the need for additional production elsewhere.

Example of CI Score Calculation in GREET

Ethanol from Corn:

Feedstock Production:

Emissions from corn farming (fertilizers, tractors). In this fase ucrop.it helps to get the CI score with the Feedstock FD-CIC calculator

Transportation:

Emissions from transporting corn to an ethanol plant.

Fuel Production:

Emissions from converting corn into ethanol (including energy used in fermentation and distillation).

Fuel Distribution:

Emissions from transporting ethanol to fueling stations.

Fuel Use:

Emissions from burning ethanol in vehicles (considering lower carbon content compared to gasoline).

CI Score: The GREET model combines these emissions data to provide a CI score, such as X g CO₂e/MJ for corn ethanol. This score helps compare the environmental impact of ethanol to other fuels like gasoline or diesel.