Wednesday, February 21, 2024

Practical use of a poultry carbon footprint tool

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By Drs. Claudia Dunkley, Brian Fairchild & John Worley

Special to Poultry Times

ATHENS, Ga. — The cumulative greenhouse gas (GHG) emissions from any human activity are commonly referred to as  the carbon footprint. A report issued by the Joint Research Center (Steinfeild, Gerber, Wassenaar, Castel, & de Haan, 2006) defines the carbon footprint as a measure of the exclusive total amount of CO2 emissions that are directly or indirectly caused by an activity or is accumulated over the life stages of a product.

A carbon footprint involves not only CO2 emissions, but also includes N2O and CH4 emissions, which are expressed in CO2 equivalents (CO2e). A CO2e is the concentration of CO2 that would give the same levels of radiative properties (the change in net irradiance at atmospheric boundaries between different layers of the atmosphere), as a given amount of CO2 (World Research Institute, 2007).

The CO2e for a given substance is calculated over a specified time period and must be stated whenever a global warming potential (GWP) is stated. The GWP is a measure of how much a given mass of GHG is estimated to contribute to global warming. For example, GWP over 100 years for N2O is 298. This means that the emission of 1 million tons of N2O is equivalent to 298 million tons of CO2 over 100 years. The GWP over 100 years for CH4 is 25 (International Panel on Climate Change, 2006).

Calculation tool

The Poultry Carbon Footprint Calculation Tool was developed and designed specifically for poultry production farms. The tool can be used to estimate the greenhouse gas (GHG) emissions from pullet, breeder, and broiler grow-out farms. The GHGs that are assessed are carbon dioxide, nitrous oxide, and methane — the gases of major concern in agriculture.

The user-friendly calculation tool is an Excel spreadsheet into which the user will enter farm data to calculate a poultry production farm’s annual carbon footprint.

The tool can be downloaded at www.poultry.uga.edu/extension/documents/GHGCalculationTool.xlsm.

In order for the file to work correctly, please be sure to enable macros.

The spreadsheet has an introductory page or tab, which informs the user of the capability and the uses of it. It provides specific directions on how to enter the information into the spreadsheet. This page also gives the growers options that can be used to reduce their energy use and subsequently to reduce their carbon footprint.

Interface page

  • Farm information and energy consumption

The “Interface” tab is the only page where the user can enter data into the tool. The user will need to select from the first drop-down box the type of poultry (broiler, pullet, or breeder) they have.

Based on the type of bird, appropriate boxes for that operation will be available for the user to input data. This information will determine the non-mechanical emissions. The non-mechanical emissions are those GHG emissions that occur from manure management and will depend on the type of poultry, the number of birds/flocks grown per year, and the type of manure management system that is used on the farm.

The user will next enter energy consumption information. Users have the options of entering LP gas, diesel, and/or natural gas. This will determine the mechanical emissions from the farm. These emissions occur from heating, incineration, diesel for tractors, generators, and other equipment on the farm. Users will also need to enter the amount of electricity used in kilowatt hours.

Electricity is used for ventilation, lighting, feed motors, and water pumps, as well as other electrical equipment for daily bird management and house maintenance. The electricity use will be reflected in the “off-farm” source in the inventory.

After entering electricity usage, the user will select from another drop-down box the region of the United States where the farm is located. The region is based on the electricity grid from which the user receives service. The tool recognizes that different parts of the country generate electricity from a different mix of sources (nuclear, coal, hydroelectric, etc.) This is an important feature that enables users from different parts of the United States to use the tool. Each region has a different emission factor, so it is important that the user select the region of the country where the poultry operation is located.

If users are unsure of the region they are in, they should click the “See Map” button. This takes users to the “Regional Maps” page, which allows them to determine which region they need to select. They can also select the “Regional Maps” tab at the bottom of the spreadsheet, which will also take them to the map.

  • Recommendations

The calculation tool also allows the user to choose house adjustments or renovations that will result in reductions in energy use and GHGs. This can be done by selecting recommendation options to reduce energy use in the “Interface” tab. The tool will show the user what the emissions would be if these adjustments were made on the farm.

The recommendations selected will affect the electricity, LPG, and/or natural gas use projections. Therefore, changes in the GHG emissions will be reflected in the mechanical and off-farm emissions inventory.

After the user selects options from the “Recommendations” section, he or she should click the “Show Projections” button. The projected year fields of the “GHG Inventory” section will be populated with the estimated emissions.

  • Greenhouse gas inventory

The “GHG Inventory” section on the “Interface” page shows users the sources of the emissions and also the amount of each GHG emitted. The inventory separates the emissions based on their source (mechanical, non-mechanical, and electricity use) and also on-farm and off-farm sources. It gives the total of each source and the total farm emissions.

The inventory is divided into two sections, “Current Year” (the actual farm emissions) and “Projected Year” (the emissions based on the energy reduction options selected). All the emissions are represented as metric tons CO2e. This inventory can be printed by selecting “Print” under the Excel file options.

Percentages

After the GHG inventory is calculated, the user will be able to view the comparison chart and the percentage chart in their respective tabs. The “Comparison Chart” page will compare the GHG emissions from the current year and that of the projected year after the recommended changes have been made.

The “Percentages” page shows the percent difference after the recommendations are made. These charts can be printed for the users’ record.

Applications

  • This tool allows users to track their emissions from year to year in their operations.
  • The Recommendations section of the tool allows the user to see where adjustments can be made on the farm to reduce emissions.
  • The Recommendations section of the tool allows the user to reduce fuel costs if the recommendations are applied.
  • The GHG Inventory section allows users to compare their current emissions per year with the projected emissions.
  • The GHG Inventory section allows users to keep records of their year-to-year emissions, which they can use to track changes.

Drs. Brian Fairchild and John Worley are professors with the University of Georgia’s Department of Poultry Science in Athens, Ga.; and Dr. Claudia Dunkley is a public service assistant with the department’s Tifton, Ga., campus.

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