Calculating Scope 3 Emissions - Add Activity Data

After completing the carbon accounting of imported financial transactions in the Carbon Ledger, you can improve the accuracy of your Scope 3 by adding Activity Data to replace the spend based averages. 

Why Do I Need to Code the Transaction in the Carbon Ledger Using Spend and then Use Activity Data?

Sumday emphasises auditability, which requires a complete, transparent emissions calculation process. This begins with coding each financial transaction in the Carbon Ledger, ensuring a solid audit trail from start to finish.

When replacing the initial spend-based calculation with a more precise measure, this occurs in a separate worksheet step. This separation preserves the audit trail while allowing calculation adjustments.

While it may feel like extra work, this systematic approach improves efficiency, minimises the chance of missing transactions, and ensures an audit-ready outcome.

How to replace Spend with Actual data for your Scope 3 emissions

  1. Go to Assessments
  2. Select your Assessment Period
  3. Go to Accounting
  4. Select Scope 3
  5. You will see all 15 Scope 3 sub-categories
  6. Click Details for any category you can improve with actual activity data

Data to calculate scope 3 using activity data

Here’s a table with examples of information you need for each category.

Category Data Data Source
Purchased Goods and Services

Start with: Importing transactions for the reporting period from your accounting system. Easily export the details into excel and upload them - ask your accountant for help if you need it or reach out. 

Enhance this data: Using quantity of goods purchased or hours of service received

Purchase orders, receipts, invoices, contracts

Financial transactions for the reporting period which can be easily exported from your accounting system.

Capital Goods Quantity of goods purchased Purchase orders, receipts, invoices, contracts. Fixed asset register.
Fuel and energy-related activities

Amount of fuel used

Energy purchased (e.g., kWh of electricity, therms of natural gas)

Invoices / Utility bills Metre reading records Contracts such as PPA (Power Purchase Agreements) Fuel purchase receipts
Transportation and Distribution

Distance and mode of transport

Mass or volume of products shipped

Site specific fuel and electricity usage and emissions

Invoices Fuel receipts Delivery notes / Transit records
Waste generated in operations

Total waste produced and type e.g. tonne/cubic metre

Proportion of this waste being treated by different methods (e.g., percent landfilled, incinerated, recycled)

Utility bills

Tracking systems

Utility bills

Tracking systems

Business travel

Destination and distance travelled by modes of transport

Nights of accommodation

Amount of fuel used

Travel agency records Travel providers e.g. airline Reimbursement receipts e.g. Fuel purchased Surveys with staff
Employee commute and WFH

Headcount

Days travelled to work and mode of transport

Amount of fuel used

Number of WFH days

Electricity and fuel used, apportioned, from WFH

HR records Surveys with employees
Leased Assets Type and number of leased assets or proportion of leased area of building Scope 1 and 2 emissions associated with lease Lease records  Utility bills
Processing of sold products Fuel and energy used related to the site Scope 1 and 2 emissions (e.g. Process and fugitive emissions if applicable) related to the site Invoices / Utility bills See Scope 1 and 2 for other potential sources
Use of sold products

Total lifetime expected uses of product(s) Quantities of products sold

Fuel used/Electricity consumed/Refrigerant leakage per use of product

Sales records / Invoices Product specifications or manuals
End-of-life treatment of sold products

Total mass of sold products and packaging (from point of sale till consumer i.e. includes any packaging that was used to transport)

Proportion of this waste being treated by different methods (e.g., percent landfilled, incinerated, recycled)

Sales records / Invoices Product specifications or manuals Tracking systems
Franchises

Emissions franchisee entities

Fuel and energy use by facility

Utility bills Rent statements and lease records
Investments Proportion of share in investment Emissions from portfolio companies Investment records

 

How to enter activity data

After navigating to the appropriate GHG Category within the Scope 3 Activity section of the product you will see a table with all the transactions and non-transaction assessment lines associated with that GHG Category.

Firstly review this table to identify transactions that could be replaced by activity data. You can do this efficiently by sorting, filter and searching across the various columns.

To then enter activity data, select the transaction (or group of transactions) and click the “Assign to Activity” button in the top right, or the “Activity” button in the “Calculation Method” column of the table. These transactions will now appear in the Activity table for you to enter the activity data.

In the activity table, to enter the activity data you must enter data in the following columns:

  • Activity Date - This is the date (Or date range) where the activity/consumption actually occured. By default this is the same as the spend date, but in some situations the activity may not actually occur on the spend date.
  • Quantity - The quantity of the activity in the UOM selected (e.g. 600 kg of vegetable purchased).
  • Emissions Source (Activity) - The emissions source that best matches the activity. This won’t necessarily match the emissions source assigned for the spend, as activity and spend emissions are often published by different datasets. E.g. you may select “General Food and Beverages” on a spend basis as this is the most appropriate option available for spend, but when entering the kg of steak you purchased, selecting “Meat Products” might be an appropriate option available to enter activity data against.
  • Units (Activity) - The unit of measure you want to enter the activity data in.

Other Activity Data Features

Some other notable features available wen entering activity data

  • From the Activity tab you can select transactions and click Revert to Spend in the top right to move them to the Spend tab where emissions will be calculated on a spend basis, regardless of whether activity data has already been entered.
  • From the Spend tab you can select transactions and click Assign to Activity in the top right to move them to the Activity tab where emissions will be calculated on an activity basis after entering a quantity, UOM and selecting an activity emissions source (If these details have already been entered it will automatically calculate the emissions on an activity basis)
  • From either the Assign, Spend or Activity tab you can select transactions and click Un-Reconcile in the top right to send those transactions back to the Carbon Ledger to have a new spend-based emissions source selected.

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