Collecting data for use in the calculation of your carbon footprint is generally the most time-intensive part of carbon accounting. This is because for most organizations this involves reaching out directly to site managers, utility providers, landlords and building managers, and accounting teams, at the very least. Why? Because these are the people who have access to the data you need.
It is becoming increasingly common for vendors to provide emissions data directly to customers based on the products and services used. Some good examples are Google Cloud and Apple products. Where available, supplier-provided emissions data is the highest quality data and should be included in your GHG inventory as published.

The remaining data used in calculating emissions falls into two main categories: actual and estimated.

Actuals, as implied, are the actual usage quantities of fuels, purchased electricity, and other sources of emissions. This data is generally extracted from invoices or online portals and can be used to calculate emissions with simple, reliable emission factors.

Estimations are usage quantities that are not based on actual consumption but are calculated using educated guesses, audits, or proxies. For example, calculating the electricity consumed in an office based on the square footage and an average consumption per square foot in that region. While estimating often does provide a reasonable backup for calculations where actuals are not available, you should always work to improve the quality of data over time and eliminate estimations wherever possible.

‍

Collecting scope 1 and 2 data 🔥

Collecting scope 1 and 2 data is generally easier than collecting scope 3 data. Here are the most common scope 1 categories and some common ways to collect the data.
Office Heating (Scope 1)
Most buildings are heated with either electricity or natural gas. If your building uses natural gas, it should be included in the scope 1 emissions of your carbon footprint.

If you pay for your natural gas, the consumption value [in units of volume (e.g. m3) or energy (e.g. kWh)] will be on the invoices. If utilities are managed by the building, request utility information from your landlord or building manager

Fuel From Company Vehicles (Scope 1)
If your company owns or leases vehicles for its employees these may be relevant to the scope 1 emissions of your carbon footprint.

Fuel usage values are generally included on invoices from suppliers and on receipts from fuel stations.

Office Electricity (Scope 2)
Office electricity consumption is included in the scope 2 emissions of your carbon footprint.

If you pay for your electricity, the consumption value [in units of energy (e.g. kWh)] will be on the invoices. If utilities are managed by the building, request utility information from your landlord or building manager.

‍

Collecting scope 3 data ✈️

Scope 3 data can in many cases be more complicated to collect and trust than scope 1 and 2 data. In many categories, the only way to determine usage quantities is to estimate using your best guess or using economic activity data (i.e. amount of money spent per category).
Below are some common scope 3 categories and recommendations on how to collect data for them.

Category 1: Purchased goods and services

• This category includes emissions from all purchased goods and services not included in the other categories.
  
• Common data types in this category include cloud server usage, IT Hardware (eg. computers, monitors), and other office or work-from-home equipment
  
• Most emissions in this category are based on the amount spent. Collect this data from your accounting software.
  

Category 2: Capital goods

• Capital goods are final products that have an extended life and are used by the company to manufacture a product; provide a service; or sell, store, and deliver merchandise.
  
• Most emissions in this category are based on the amount spent. Collect this data from your accounting software.
  

Category 8: Upstream Leased Assets

• Any emissions from leased assets not accounted for in scopes 1 and 2 are included in this category
  
• For most organizations, this includes water used in the office
  
• If you pay for your water, the consumption value [in units of volume (e.g. L)] will be on the invoices
  
• If utilities are managed by the building, request utility information from your landlord or building manager
  

Category 5: Waste

• Waste generates emissions when disposed of. The emissions vary based on the type and how it is disposed of
  
• Collect waste data from your waste management service provider, from your landlord, or perform a simple estimate
  

Category 6: Business travel

• The most common types of business travel that contribute to GHG emissions are air travel, hotel stays, and Uber/taxi rides for members of your team while traveling for work purposes.
  
• These all have emissions which should be included in your carbon footprint.
  
• If you use a travel booking system (e.g. Concur) there may be travel or emissions data available in the system. Otherwise, this information will be available in receipts and expense reports
  

Category 7: Employee commuting (including work-from-home)

• If any employees commute to a physical office, the emissions from their travel can be accounted for in this category
  
• To get information on employee commute habits, we recommend conducting a survey to determine how your team commutes to the office (eg. by car, bus, subway, etc.),  how frequently they come in, and how far they travel
  
• While work from home emissions can also be calculated on a per-employee basis, this is not required
  

Estimating activity data for your carbon footprint ✖️

If you use an emissions source on a site but are unable to collect actual data, you should estimate your consumption to fill the gap.
While there are no comprehensive guides to estimating data across each scope and category, we have provided several guidelines and examples to help you perform these calculations.

‍

Activity data estimation principles ⚖️

These are a few basic principles to follow when estimating activity data for your GHG inventory:

• When estimating any type of data - whether scope 1, 2, or 3 - it is important to be logical and show your work
  
• Where possible, find a trusted 3rd party reference containing a detailed methodology for estimating the relevant activity, and reference the source in your calculations
  
• When estimating to fill data gaps, try to compare to historical data, other organizations like yours, and/or assess whether the final value seems reasonable
  

If estimation is necessary for your inventory, you should try to improve the quality of your estimations over time. Here are some ways to do that:

• The more of your methodologies, proxy values, estimation factors, and calculations are based on trusted 3rd parties, the better
  
• If a category is estimated in the previous year, try to find ways to collect actual data for the current year
  
• Where estimates are used every year, try to be consistent in the approach used
  

Estimating scope 1 and 2 data ⚡️

Estimating to fill scope 1 and 2 gaps can be done using the following best-practices based on the GHG Protocol.
Mobile Combustion
To estimate emissions from mobile fuels without access to primary consumption data, we recommend collecting as much information as possible on distance travelled, vehicle type, fuel used, and if possible, spend data. Consumption can be estimated in a variety of ways depending on the available data. E.g. if only spend data is available, determine the average price per unit of fuel and divide the spend data by that value to determine the total volume used. State the estimation methodology in the document you use to calculate them.

Stationary Combustion
For natural gas emissions, estimations can be performed using facility square footage and building type combined with a US Department of Energy (CBECS) estimation factor (Source, table c24).
For other stationary emissions, follow a similar procedure to that recommended for Mobile Combustion.

Purchased Energy
For purchased electricity emissions, estimations can be performed using facility square footage and building type combined with a US DOE estimation factor (Source, table c14).

Fugitive Emissions
We recommend using the US EPA “Screening Method” which determines annual leakage of refrigerant gases based on the gas, the total storage capacity, and the annual leakage rate of the given equipment type (Source).

‍

Estimating scope 3 data 🖥

When estimating any type of data, including scope 3, there are two main methods:
Use trusted estimation factors

• Estimation factors (also called intensities) are values that can be multiplied by commonly available information (e.g. building square footage or company headcount) to calculate an adequate estimate of an activity or emissions value
  
• These factors are commonly based on analysis of a large set of data and provide a reasonable proxy for calculations
  
• For example, the US Department of Energy publishes electricity, natural gas, and other intensity factors based on a survey called CBECS (Source, eg. natural gas is table C24)
  

Estimate using other methods

• When estimation factors are unavailable, the best next step is to do research to find a description of an estimation methodology from a trusted source
  
• Common sources are the GHG Protocol, US EPA, UK DEFRA, climate consultancies like Eco-Act or Anthesis, etc.
  
• If you can find and follow a relevant methodology from one of these sources, you are likely to end up with a fairly accurate, defensible estimate
  

There are also trusted scope 3 category calculation tools and methodologies that can make your life easier, including these ones:

• For air travel data, use the ICAO air travel emissions estimator
  
• For hospitality data, use the Hotel & Conference Footprinting Tool or the US EPA Event Emissions Guide
  
• For work-from home emissions, try the methodologies published by Eco-Act or Anthesis
  

How to correctly format activity data for calculation (or for easy upload to a carbon accounting tool) 📝

When preparing your activity data for calculation, there are only a few essential values you need for each data point.
These should be all you retain in your final upload document (if you are using Breeze) or your final calculation spreadsheet (if you are doing your calculations manually.

The columns you need are:

1. Source name. The unique name of your emissions source.
   
2. Place name. The unique name of the facility or site the data point relates to. If the data point does not have a place (on business travel data, for example) you can leave this line blank.
   
3. Start and end dates. The relevant time period of the entry.
   
4. Usage quantity. The quantity that will be used in calculations.
   
5. Usage unit. The unit of measure (UOM) of the usage quantity.
   
6. Notes. Any additional relevant information pertaining to the data point.
   

A few additional points to note:

• Each data point should be on its own line
  
• Source and Place names should match any system values exactly, including upper and lower case letters.
  
• Dates should be formatted as YYYY-MM-DD if possible, but you can upload other date formats without issue.
  
• Unit symbols should match system values exactly, including upper and lower case letters.
  
• Use the template below to ensure you use the correct unit symbols.
  

‍