Introduction to the Calculator

The EPA’s Simplified GHG Emissions Calculator is designed to help businesses of all sizes take control of their environmental impact. This user-friendly tool looks at both Scope 1 direct emissions and Scope 2 indirect emissions, providing a comprehensive view of your carbon footprint. Leveraging the calculator is essential for accurately tracking and managing emissions, enabling organizations to identify key areas for improvement and make informed decisions that drive sustainability efforts.

The EPA Simplified GHG Emissions Calculator is a user-friendly tool that helps organizations estimate their yearly greenhouse gas emissions in the US. It uses the latest guidelines and data from the Environmental Protection Agency (EPA) to calculate emissions. By inputting their activity data, organizations can determine both their direct and indirect emissions for the year. The Calculator allows the user to estimate GHG emissions from scope 1 (direct), scope 2 (indirect), and some scope 3 (other indirect) sources.

This article focuses on Scope 1 emissions by reviewing each tab individually to help you navigate the tool. For a general overview of concepts review within the calculator, check out my Simplified Guide to Greenhouse Gas Management for Organizations.

Operational Boundaries

With regards to emission sources, a typical office-based organization will likely have the following (scope 1 and 2) emissions sources: stationary combustion, refrigeration and air conditioning, and electricity. For those in the industrial sector, such as pulp and paper, cement, chemicals, and iron and steel, you may have sector- specific emission sources that are not covered by the Calculator. Instead, look to EPA’s Greenhouse Gas Reporting Program (GHGRP) which provides guidance and tools that can aid in the calculation and reporting of these emissions.

If you answer “yes” to a scope question below, that emissions source should be included in your scope 1 inventory.

Scope 1 Inventory Inclusion:

1. Stationary Combustion: Do you have facilities that burn fuels on-site (e.g., natural gas, propane, coal, fuel oil for heating, diesel fuel for backup generators, biomass fuels)?
2. Mobile Sources: Do any vehicles fall within your organizational boundary?  This can include cars, trucks, propane forklifts, aircraft, boats.  Only vehicles owned or leased by your organization should be included here.
3. Refrigeration and Air Conditioning: Do your facilities use refrigeration or air conditioning equipment?
4. Fire Suppression: Do your facilities use chemical fire suppressants?
5. Purchased Gases: Do you purchase any industrial gases for use in your business?  These gases may be purchased for use in manufacturing, testing, or laboratories.        

Emissions from Stationary Combustion Sources

Stationary combustion sources include things like natural gas hot water heaters or oil-burning boilers in buildings. These sources emit greenhouse gases when they burn fuel to produce heat or hot water. To track these emissions, you need to know the type and amount of fuel used at each location. This information usually comes from utility bills, like a monthly natural gas bill.

Data Collection Checklist:

1. Type of fuel consumed
2. Amount of fuel consumed

If you are one of many tenants in a building and don’t know the exact amount of fuel your space uses, you can estimate it by multiplying the total fuel usage of the building by the percentage of the floor area your organization occupies. Companies with home offices can also include these in their inventory if they can reasonably estimate the energy used for business activities. The Energy Information Administration (EIA) conducts a Commercial Building Energy Consumption Survey and provides average energy consumption by building type per square foot.

Emissions from Mobile Sources

Mobile sources refer to the direct release of greenhouse gases from vehicles and other moving machinery owned or controlled by a company. This includes company cars, trucks, buses, and construction equipment that burn fuel like gasoline, diesel, or natural gas. Essentially, it’s the pollution produced by vehicles that the company directly operates, where emissions are calculated based on the fuel burned.

Data Collection Checklist:

1. The types and years of the vehicles.
2. The amount of fuel used during the reporting period.
3. The miles driven by each vehicle during the reporting period.

You can find this information from fuel receipts, purchase records, and vehicle logs. If you can’t find the exact data, you can estimate using fuel economy information from the vehicle manufacturer or websites like www.fueleconomy.gov.

The first step in categorizing your mobile sources is to divide vehicles into two categories: on-road and non-road.

On-road vehicles with their associated fuel type include:

• Passenger Cars (gasoline or diesel)
• Light-Duty Cars (methanol, ethanol, CNG, LPG, biodiesel)
• Light-Duty Trucks (gasoline, diesel, ethanol, CNG, LPG, LNG, biodiesel)
• Medium-Duty Trucks (CNG, LPG, LNG, biodiesel)
• Heavy-Duty Trucks (methanol, ethanol, CNG, LPG, LNG, biodiesel)
• Medium- and Heavy-Duty Vehicles (diesel)
• Motorcycles (gasoline)
• Buses (methanol, ethanol, CNG, LPG, LNG, biodiesel)

Vehicle classification guidelines:

• Passenger cars are automobiles used primarily to transport 12 people or less for personal travel, and are less than 8,500 lbs in gross vehicle weight.
• Light-duty trucks are vehicles that primarily transport passengers such as sport utility vehicles (SUVs) and minivans. This category also includes vehicles used for transporting light-weight cargo which are equipped with special features such as four-wheel drive for off-road operation. The gross vehicle weight normally ranges around 8,500 pounds or less.
• Medium- and heavy-duty trucks are vehicles with a gross vehicle weight of more than around 8,500 pounds, such as single unit trucks, combination trucks, tractor-trailers, and box trucks used for freight transportation. In addition, this category includes some vehicles that are not typically used for freight movement such as service and utility trucks.  
• Company-owned private jets or planes should also be included, and are categorized by fuel type (i.e., Aviation Gasoline Aircraft, Jet Fuel Aircraft). 

Non-road vehicles with their associated fuel type include:

• Ships and Boats (residual fuel oil, gasoline – 2 stroke, gasoline – 4 stroke, diesel)
• Locomotives (diesel)
• Aircraft (jet fuel, aviation gasoline)
• Agricultural Equipment (gasoline – 2 stroke, gasoline – 4 stroke, gasoline off-road trucks, diesel equipment, diesel off-road trucks, LPG)
• Construction/Mining Equipment (gasoline – 2 stroke, gasoline – 4 stroke, gasoline off-road trucks, diesel equipment, diesel off-road trucks, LPG)
• Lawn and Garden Equipment (gasoline – 2 stroke, gasoline – 4 stroke, diesel, LPG)
• Airport Equipment (gasoline, diesel, LPG)
• Industrial/Commercial Equipment (gasoline – 2 stroke, gasoline – 4 stroke, diesel, LPG)
• Logging Equipment (gasoline – 2 stroke, gasoline – 4 stroke, diesel)
• Railroad Equipment (gasoline, diesel, LPG)
• Recreational Equipment (gasoline – 2 stroke, gasoline – 4 stroke, diesel, LPG)

Unless used in pure form, biofuel (biodiesel or ethanol) is typically mixed with a petroleum fuel (diesel or gasoline) for use in vehicles. This means that, although biomass CO2 emissions from biofuels are not counted in the total emissions because they are considered net zero, the petroleum fuel content of the mix will need to be factored in. To accurately quantity biofuel emissions, you’ll therefore need to determine which of these two fuels is being mixed with petroleum, then find the percentage for that fuel for the calculation. For hybrid vehicles, mileage and fuel usage is reported the same as for conventional vehicles. In cases where exact mileage or fuel usage is unavailable, use fuel efficiency (miles per gallon) to estimate the missing data point.

Emissions from Refrigeration and Air Conditioning Equipment

Refrigeration and AC equipment can vary widely in size depending on the organization. Emissions within this category occur due to the leakage of climate-impacting chemicals during use, maintenance, and disposal of this equipment. In office-based organizations, these emissions are usually small. For example, a small office might have just one rooftop AC unit, whereas a grocery store chain might have several, in addition to other refrigeration equipment.

Under GHG Protocol guidelines, HFCs, PFCs, CO2, and SF6 refrigerants from facilities and vehicles must be included in a company’s inventory. However, ozone-depleting substances like chlorofluorocarbons (CFCs) or “freon” and hydrochlorofluorocarbons (HCFCs) are typically excluded from the GHG inventory due to international regulations or reported separately as memo items. One reason to track CFCs and HCFCs is to explain increases in newer “replacement” chemicals like HFCs and PFCs as the old chemicals (CFCs and HCFCs) get phased out.

Data Collection Checklist (by equipment):                                    

1. Refrigerant purchase, inventory, and disposal data
2. Inventory of equipment by facility  
3. Refrigerant capacity of equipment 
4. Amount of refrigerant (HFC and PFC) emitted over the inventory reporting period
5. Optional: Track HCFC and CFCs, such as R-22               

To estimate emissions from refrigeration and air conditioning equipment, organizations are provided with three methods, each varying in complexity and data requirements. Listed from most (1) to least (3) preferred, these are:

1. Material Balance Method
2. Simplified Material Balance Method
3. Screening Method

The Material Balance Method is the most detailed and preferred approach for estimating emissions by tracking total gases stored and transferred within the organization. This method is recommended for organizations that maintain their own equipment and requires available data on the total inventory of refrigerants at the beginning and end of the reporting period, purchases during the reporting period, and changes in total equipment refrigerant capacity. The Material Balance Method can also be used to calculate emissions from fire suppression equipment. Think of this method like balancing your checkbook. You’re keeping track of all the refrigerant that goes into and comes out of the system over time. You start with how much refrigerant is in your equipment at the beginning, add any refrigerant you put in during maintenance, subtract any you take out, and then see what’s left at the end. The difference tells you how much refrigerant might have leaked out and therefore contributes to emissions. This method works best for detailed, accurate tracking when you have good records and need precise data.

Within the EPA calculator, the Material Balance Method is based on the following inputs:

• Inventory Change: Difference of gas stored in inventory from beginning to end of reporting period.
  • Includes only gas stored on-site (i.e. cylinders) and not gas contained within equipment.
• Transferred Amount: Gas purchased minus gas sold/disposed during reporting period.
  • Gas purchased includes:  Purchases for inventory, as part of equipment servicing (not from inventory), within purchased equipment, and gas returned to the site after off-site recycling.
  • Gas sold/disposed includes:  Returns to supplier, sales or disposals (including within equipment), and gas sent off-site for recycling, reclamation, or destruction.                                             
• Capacity Change: Capacity of all units at beginning minus capacity of all units at end of reporting period.
  • Can be assumed to be capacity of retired units minus capacity of new units.

The Simplified Material Balance Method and may be more appropriate for entities that do not maintain and track refrigerant supply, and that have not retrofitted equipment to use a different refrigerant during the reporting period. This method tracks emissions from equipment installation, operation, and disposal, and is recommended for organizations that have contractors service their refrigerant-containing equipment. However, rather than tracking every detail, you use general estimates. With this method, you take the total amount of refrigerant in the system and assume a typical percentage might leak out each year (like an average rate). You also estimate how much might be lost when the equipment is retired. This gives you a quick, albeit less precise, estimate of emissions and works best for situations where you need a fairly good estimate but do not have detailed records.

Within the EPA calculator, the Simplified Material Balance Method is based on the following inputs:

• New Units: Units installed during reporting period (do not include any data for new units pre-charged by the supplier), disposed units were disposed of during the reporting period, and existing units are all others.
• Charge/Recharge: Gas added to units by organization or a contractor (do not include pre-charge by manufacturer).
• Capacity: Sum of the full capacity for all units (do not include new units pre-charged by manufacturer).
• Amount recovered: Total gas recovered from all retired units.                                                                                

The Screening Method is the quickest way to generate a rough guess of your emissions from refrigeration and air conditioning equipment based on common industry knowledge. This method uses standard factors or averages that experts have developed, based on typical equipment and operating conditions. Rather than measuring or estimating anything yourself, you simply apply these standard numbers to get a rough idea of emissions. This works best for early stages of assessing emissions or when you just need a ballpark figure to see if you should investigate further.

Within the EPA calculator, the Screening Method is based on the following inputs:

• Equipment Type (or closest available): See below for types of equipment available for selection within the calculator.
• Refrigerant Added: Amount of refrigerant added by the organization to new units. If no refrigerant was added (because it was pre-charged by the manufacturer), leave this field blank.
• Months in Operation: Number of months the unit was in operation during the year (0-12). For example, if the unit was installed in July, enter 6.
• Refrigerant Capacity: Refrigerant capacity by equipment type and refrigerant for all units operating and disposed of during the reporting period.

The Screening Method requires an inventory of equipment by type. Types of refrigeration and air conditioning equipment include:

• Domestic Refrigeration
• Stand-Alone Commercial
• Medium/Large Commercial
• Transport Refrigeration
• Industrial Refrigeration (industrial, food processing and cold storage units)
• Chillers (commercial)
• Residential/Commercial A/C (residential and commercial units, including heat pumps)
• Maritime A/C Units
• Railway A/C Units
• Buses A/C Units
• Other Mobile A/C Units

Due to data limitations, many organizations may find the Screening Method to be the most practical. However, if emissions calculated using this method are found to be significant, it is advisable to reconsider using either of the Material Balance Methods for improved accuracy.

Note that Scope 1 GHG emissions are only those resulting from operations at the reporting organization’s facilities. For refrigeration and air conditioning these emissions may take place during installation, use, or disposal. Refrigerants and may be released from equipment leaks during normal operation or from catastrophic leaks. Also, when equipment is installed, repaired, or removed, refrigerants may be released if proper recovery processes are not used.

Emissions from Fire Suppression Equipment

Emissions from fire suppression equipment can vary widely, ranging from small portable fire extinguishers to large-scale fire suppression systems used in office buildings or warehouses. These emissions are typically caused by the release of chemicals such as HFCs or CO2 during the use, maintenance, or disposal of fire suppression devices. HFCs, PFCs, and CO₂ fire suppressants must be included in the GHG inventory. Other fire suppressants like Halon compounds, HCFCs, aqueous solutions, and inert gases are typically excluded.

Data Collection Checklist (by equipment and/or facility):

1. Fire suppressant purchase, inventory, and disposal data.
2. Inventory of equipment by facility.
3. Fire suppressant capacity of equipment.
4. Amount of fire suppressant (HFC and PFC) emitted during the reporting period.

This information is usually collected from maintenance and inspection records, work orders, or invoices from contractors. If you cannot find the list of propellants or chemicals used in the fire extinguisher, contact the manufacturer for this information.

Estimating emissions from fire suppression equipment is similar to estimating emissions from refrigeration and air conditioning equipment in organizations are asked to select from the three of the following estimation methods: 

1. Material Balance Method
2. Simplified Material Balance Method
3. Screening Method

See the section on Emissions from Refrigeration and Air Conditioning Equipment for greater detail on the three methods.

The Screening Method requires categorizing your fire suppression emissions is to divide equipment into two categories: fixed and portable. Different fire suppression leak rates are attributed to each type: a standard default rate of 3.5% for fixed and a rate of 2.5% for portable equipment.

Note that Scope 1 GHG emissions are only those resulting from operations at the reporting organization’s facilities. For fire suppression these emissions may take place during installation, use, or disposal. Fire suppressants may be released from equipment leaks during normal operation or from catastrophic leaks. Also, when equipment is installed, repaired, or removed, fire suppressants may be released if proper recovery processes are not used.

Emissions from Purchased Gases

Industrial gases are sometimes used in processes such as manufacturing, testing, or laboratory uses. For example, CO2 gas is often used in welding operations. Since these gases are typically released to the atmosphere after use (i.e. on-site), they are included within the Scope 1 inventory. Any releases of the seven major greenhouse gases (CO2, CH4, N2O, PFCs, HFCs, SF6, and NF3) must be included in the GHG inventory. Ozone-depleting substances, such as CFCs and HCFCs, are regulated internationally and are typically excluded from a GHG inventory or reported as a memo item.

It is assumed that all gas purchased within the reporting period is used and released within that same period. If your business buys gas in bulk for use over several years, you should divide the total amount by the number of years of usage and report that portion annually. Remember to report bulk gas purchases in future years as well.

Data Collection Checklist (for all applicable facilities):

1. Type of gas purchased
2. Amount of gas purchased
3. Purpose for the gas

List of gases for consideration:

Note that Scope 1 GHG emissions are only those resulting from operations at the reporting organization’s facilities. Emissions that occur during the manufacturing or disposal of equipment or purchased gases are Scope 3 indirect emissions and are not included in an organization’s Scope 1 emissions.