Written May, 2024
File A1-79

Scope 1 and 2 Carbon Calculator

The Scope 1 and 2 Carbon Calculator Decision Tool was created as a way for businesses and individuals to easily estimate their Scope 1 and 2 carbon emissions in accordance with the World Resources Institute Green House Gas Protocol. Instructions included here show screenshots from the example version and will explain how to calculate your emissions according to the "operational control" method, where you account for all emissions coming from equipment or processes that you or your business control such as electricity use, fleet vehicles, or heating and cooling a building. This tool is not meant to replace formal audited carbon inventories, but is rather a way for businesses and individuals to track their carbon emissions and recognize impacts. Please note that entries are only entered in GREEN, unprotected cells. ORANGE cells have drop-down menu options required for each entry. All other cells are protected and will calculate automatically when information is entered completely. Each worksheet allows for up to 500 entries, with the dashboard able to summarize one to 44 years of data.

Dashboard

The dashboard displays estimated emissions according to location-based calculations or using the chosen eGRID region for electric emissions. Data must be entered on the various worksheets before the Dashboard will populate with information. To use the Dashboard, please put the year(s) to view in the "Year" column. This will pull data from the rest of the workbook that has the same year.

Dashboard screenshot

You can also graph any year that you have entered data for. Select a year from Table 1, and the information will be displayed in the graph below in Metric Tons of Carbon Dioxide Equivalents.

Dashboard graph screenshot

Below the graph, also displayed is information on how many urban trees during a 10-year time frame it would take to capture that much carbon dioxide or how many passenger cars operating for a year it would take to produce that many carbon dioxide equivalents.

Dashboard total emmisions

Vehicles

The "Vehicle" worksheet is for calculating emissions from passenger vehicles, light-duty vehicles, and medium- and heavy-duty vehicles. Please start by typing a name or ID for the vehicle you want to add data for in the "Name/ID" column (Column A).

In the next column, "Year of Data" (Column B), put in the year the information is for. In "Year of Vehicle" (Column C), put the year the vehicle was made.

After this, you must enter the miles the vehicle traveled in the selected year in Column D and the average miles per gallon (MPG) in Column E. The annual MPG can be found on a vhicle dashboard or use an estimate based on recent fuel usage.

Vehicles-user entries

In Column F, there is a fuel type drop-down menu to select if the vehicle runs on gasoline or diesel.

Column G has a drop-down menu to pick if the vehicle is a passenger vehicle (car, hatchback, etc.), light-duty vehicle (SUV, truck, etc.), or medium and heavy-duty vehicle (semi or truck with gross vehicle weight rating over 8,501 lbs). Once all information has been added, the worksheet will calculate how many gallons of fuel each entered vehicle should have used, the kilograms of carbon dioxide equivalents, and metric tons of carbon dioxide equivalents.

Vehicles-table

Equipment

The "Equipment" worksheet is for calculating emissions from any equipment that uses fuel, such as lawnmowers, forklifts, boats, or recreational equipment. Please start by typing a name or ID for the equipment you want to add data for in the "Name/ID" column (Column A). In the next column, "Year of Data" (Column B), enter the year of the information. Next, in Column C, put the gallons of fuel used in the data year by the specific equipment.

Equipment-user entries

In Column D, or "Equipment Type" there will be a drop-down menu to select the best fitting category for the equipment. Column E is then a drop-down menu for the type of fuel/motor of the equipment. If all information is entered correctly, the emissions will be calculated and appear in the final two columns.

Equipment-table

Heating

The "Heating" worksheet is for calculating emissions from heating a building or space. Begin by typing a name or ID for the heating method or space in Column A and the year of the data in Column B.

Heating-user entries

To the right of the Key, there is a tool to help calculate the mmBtu (heat units) of a heating method. Use the drop-down menu to select a heating method, and the tool will calculate how many mmBtu are in each unit of measurement for that heating method. For example, if we select propane, the unit of measurement is in gallons and each gallon of propane is 0.091 mmBtu.
Next, you can then enter the amount of the units (gallon, short ton, etc.) used in the selected year. It will then calculate how many mmBtu used in the year based on the heating method. Note that it will calculate the mmBtu in cell L11 based on the heating method selected in cell K7 (heating method chosen in cell above).
Heating-side calculator

Results from the unit calculator can then be entered in Column C or "mmBtu of Heating Method". Confirm the correct heating method is selected from the drop-down menu in Column D and emissions for that heating method and volume of fuel used will be calculated in Columns E and F.

Heating-table

Refrigerant

The "Refrigerant" worksheet is for calculating the emissions of known refrigerant leakage. It is important to note that this data is often not available from the start and may not be a significant share of total emissions depending on the business or individual. If there is only one AC unit, that is newer or does not leak, the refrigerant emissions will most likely be insignificant and do not have to be calculated. If data is not available for this particular worksheet, skip this section and move on to use the rest of the Decision Tool.

To continue on the Refrigerant worksheet, start by typing a name or ID for the unit losing refrigerant in Column A and the year of the data in Column B. In Column C, please choose the amount of refrigerant lost during the year in kg. In Column D, please select the refrigerant type from the drop-down menu. There is a pound to kilogram converter provided to the right on this worksheet.

Refrigerant-table

A good way to estimate the amount of refrigerant lost during a year is to ask the maintainer of the units how much refrigerant was recharged, or added, to the unit during the given year. If this was not tracked previously, you will likely overestimate the refrigerant loss, but if done regularly, it is a good way to estimate the refrigerant lost by the unit annually.

Processing Sources

The "Processing Sources" worksheet is for accounting for emissions from chemical processing, such as fermentation. This section can be skipped for most individuals and general businesses. Due to the large range of processes and unknown emission factors, the amount of CO2, CH4, and N2O must be added manually. However, entries will automatically be converted to CO2e. To begin, enter a name or ID for the unit producing GHGs in Column A and the year of data in Column B. In column C, please add the amount of gas produced during the chosen year in kilograms. In column D, please select the gas type from the drop-down menu.

Processing Sources-table

Electricity

The "Electricity" worksheet is for calculating the emissions from electricity use. To begin, enter a name or ID for the location using electricity in Column A and the year of data in Column B.

In Column C, please add the kWh of electricity used during the year. This can be found on a utility bill or requested from the utility company. Since utility bills do not typically end exactly at the start and end of the month, choose 12 utility bills that best match the year or time frame that align with the period first trying to measure. Then, for the following year, use the next 12 bills, making sure to start after the last bill used from the previous year. This will account for all energy usage over the time frame being analyzed.

Energy-user entries

In Column D there is a drop-down menu to select the eGRID region. This region is used to find how ‘dirty’ your electricity is based on the average of all electricity production in the region. If you do not know your eGRID region, find it using the map image in the Decision Tool or search by zip code through the Environmental Protection Agency Power Profiler website. After the eGRID region is selected, total emissions from electricity will be calculated and appear in Columns E and F.

Energy-table

Once information is entered on each respective worksheet, return to the Dashboard to summarize the information for any given year. Calculations used in this tool are based on World Resources Institute Green House Gas Protocol as of 2024, the EPA's 2023 Emission Factor Hub, and the 2023 release of the eGRID Summary Tables. The Decision Tool will be updated periodically to reflect any changes to the standard or emission factors.

Abbreviations

MT – Metric Tons
CO2E – Carbon Dioxide Equivalents
CO2 – Carbon Dioxide
CH4 – Methane
N2O – Nitrous Oxide
mmBTU – One million British Thermal Units

Additional Resources:
Corporate Green (used to make this tool)
World Resources Institute Standards
EPA’s eGRID Data Explorer
American Housing Survey Table Creator
EPA Emission Factors Hub


Kurt A. Rosentrater, professor, Agricultural and Biosystems Engineering karosent@iastate.edu
Shelby Nechkash, research assistant, nechkash@iastate.edu

Author

Kurt Rosentrater

professor Agricultural and Biosystems Engineering
View more from this author

Shelby Nechkash

research assistant

Use this Decision Tool to estimate Scope 1 and 2 carbon emissions for a business or farm operation: Scope 1 and 2 Carbon Calculator for Businesses and Individuals or download the "Example version" of the Decision Tool.