GHG Footprint
Definition:
The GHG Footprint is the amount of greenhouse gas emissions that ReFED estimates would result from a given food surplus management scenario.
GHG Footprint Equation:
GHG Footprint = Sum of Tons Surplus Sent to Each Destination * ( Upstream MTCO2e per ton + Downstream MTCO2e per ton for Each Destination )
Equation for Net Benefit of Alternative Scenario:
Net Benefit = GHG Footprint of Current Scenario - GHG Footprint of Alternative Scenario
The following table includes an example calculation to illustrate this methodology as implemented in the Impact Calculator.
DATA ITEM |
DATA SOURCE OR CALCULATION |
EXAMPLE |
|---|---|---|
Sector |
User provided |
Retail |
Weight of Food by Destination (Current Scenario) |
User provided |
A grocery retail sustainability manager wants to understand the potential GHG impact that could be expected from a new technology solution to prevent surplus of fruit and vegetable produce in their stores. They also want to start donating perfectly-good-to-eat produce that is currently being landfilled just because it’s past the ‘sell by’ date.
Currently, they estimate the following annual breakdown of their produce surplus by destination:
20 tons donated
30 tons composted
50 tons landfilled
———————————
100 tons total annual produce surplus
|
Weight of Food by Destination (Alternative Scenario) |
User provided |
Based on a recent analysis from a hired consultant, they estimate that 50% of the food they’re currently sending to compost and landfill could be prevented by the new prevention technology. They also think that an additional 5 tons of the food that they’re currently landfilling because it’s past the ‘sell by’ date is perfectly-good-to-eat produce that could be donated instead. This would be the new destination breakdown after implementing the prevention solution and increased donations:
40 tons prevented
25 tons donated
15 tons composted
20 tons landfilled
_____________________
100 tons total
|
Upstream GHG Factors |
Developed from data provided by Quantis (See Appendix A for more detail on GHG Factors) |
As listed in Appendix A, these are the following Upstream GHG Factors for surplus produce at Retail:
Prevention: 0 MTCO2e per Ton (this assumes that each unit of food surplus prevented results in 1 less unit of food production required to meet demand so the production emissions cancel each other out)
Donations: 0.680592 MTCO2e per Ton (this assumes that each unit of food donated results in 0.5 units less of food production required to meet demand)
Composting: 1.361184 MTCO2e per Ton (includes production, storage, and transport through the Retail stage)
Landfill: 1.361184 MTCO2e per Ton (includes production, storage, and transport through the Retail stage)
|
Downstream GHG Factors |
Developed from data provided by Quantis (See Appendix A for more detail on GHG Factors) |
As listed in Appendix A, these are the following Downstream GHG Factors for surplus produce at Retail:
Prevention: 0 MTCO2e per Ton
Donations: 0.013715 MTCO2e per Ton (assumes 4.18% of donated food ends up being landfilled instead of donated)
Composting: 0.034810 MTCO2e per Ton (includes transport to compost facility, energy use to turn compost piles, fugitive emissions, and assumes compost will be used as a fertilizer and soil amendment offset)
Landfill: 0.328308 MTCO2e per Ton (includes transport to landfill, fugitive methane emissions, energy recovery offset, and landfill carbon storage)
|
Current Scenario GHG Footprint |
= Current Tons Donated * (Upstream + Downstream GHG Factors for Donations) +
Current Tons Composted * (Upstream + Downstream GHG Factors for Composting) +
Current Tons Landfilled * (Upstream + Downstream GHG Factors for Landfill)
|
= 20 tons donated * ( 0.680592 MTCO2e per ton + 0.013715 MTCO2e per ton ) +
30 tons composted * ( 1.361184 MTCO2e per ton + 0.034810 MTCO2e per ton ) +
50 tons landfilled * ( 1.361184 MTCO2e per ton + 0.328308 MTCO2e per ton )
= 140 MTCO2e
|
Alternative Scenario GHG Footprint |
= Alternative Tons Prevented * (Upstream + Downstream GHG Factors for Prevention) +
Alternative Tons Donated * (Upstream + Downstream GHG Factors for Donations) +
Alternative Tons Composted * (Upstream + Downstream GHG Factors for Composting) +
Alternative Tons Landfilled * (Upstream + Downstream GHG Factors for Landfill)
|
= 40 tons prevented * ( 0 MTCO2e per ton + 0 MTCO2e per ton ) +
25 tons donated * ( 0.680592 MTCO2e per ton + 0.013715 MTCO2e per ton ) +
15 tons composted * ( 1.361184 MTCO2e per ton + 0.034810 MTCO2e per ton )
20 tons landfilled * ( 1.361184 MTCO2e per ton + 0.328308 MTCO2e per ton )
= 72 MTCO2e
|
Net Benefit of Alternative Scenario |
= Current Scenario GHG Footprint - Alternative Scenario GHG Footprint |
= 140 MTCO2e - 72 MTCO2e
= 68 MTCO2e avoided under the alternative scenario
Click here to see this example in the ReFED Impact Calculator.
|