Scope 1, 2 and 3 emissions: where do you start with a carbon calculation?

Are the gas coming out of a factory’s smokestack, the emissions caused at a power plant by the electricity the factory buys, and the emissions produced in making the steel the factory purchases the same thing? All three are tied to the factory’s footprint, but their control, data and responsibility are very different. A carbon calculation starts by making this distinction.

Scopes 1, 2 and 3 are the common classification that divides greenhouse gas emissions into three groups according to a business’s control over the source of the emissions. In this article we explain what each scope includes, which data feeds which scope, and in what order you can start the calculation with a platform such as Karbonİz.

The purpose of the classification is to prevent the same emission from being counted in more than one place and to make the owner of each item clear. Scopes 1 and 2 can be calculated with the business’s own data; Scope 3 requires a joint data effort with suppliers, customers and carriers. This difference between the scopes also shows in advance, when you begin the calculation, how much effort each item will take.

Scope 1: direct emissions

These are emissions from sources that the business owns or directly controls. Because the source is in your own facility or vehicle, it is the scope that is easiest to take ownership of. Typical examples include natural gas burned in boilers and furnaces, fuel consumed in company vehicles, emissions from the production process itself, and refrigerant gas leaks.

• Where the data is: fuel and gas invoices, fleet fuel records, facility meters.
• Calculation logic: the quantity of fuel consumed multiplied by the relevant emission factor.
• Watch out: if the list of facilities and vehicles is not complete, the scope quietly shrinks.

Scope 2: purchased energy

These are indirect emissions arising from the generation of purchased electricity, steam, heating and cooling. The emission occurs at the plant that produces the energy but is written to the account of the business that consumes it. Because this scope relies on measured consumption data, it is usually well traceable; the most critical input is the emission factor selected for the correct period.

• Where the data is: energy meters and energy invoices such as electricity and steam.
• Calculation logic: the quantity of energy consumed multiplied by the factor used; the version of the factor should be recorded.
• Opportunity: the effect of switching to renewable energy is seen most in this scope.

Scope 3: the value chain

These are the other indirect emissions that arise in the value chain outside the business’s control but as a result of its activity. Purchased goods and services, suppliers’ production, inbound and outbound transport, business travel, employee commuting, waste and the use of the sold product fall into this group. The data is mostly outside the business, so the Scope 3 calculation is the most scattered area and the hardest to verify.

• Where the data is: ERP purchasing records, logistics and transport data, suppliers’ product carbon footprint (PCF) data.
• Calculation logic: direct supplier data is used if it exists; if not, an estimate based on spend or quantity.
• Watch out: do not present estimated data and measured data from a supplier with the same confidence.

Where should you start the calculation?

1. Draw the boundary. Which facilities, which companies and which period will be included? A calculation without a clear boundary, however detailed, cannot be compared between years.
2. Start with Scopes 1 and 2. The data sits inside the business, on invoices and meters. You get results quickly, and you also learn here how to trace the calculation.
3. Prioritise Scope 3. Instead of trying to calculate all items at once, start with the items that look large, such as purchasing and logistics; ask your most important suppliers for direct data.
4. Do not double count. Make sure the same emission does not appear in two scopes at once; which scope each item is written to should be on record.
5. Mark data confidence from the start. For each item, state whether it is measured, estimated or missing. Karbonİz’s data quality score shows this information next to the result.

Draw the boundary first, then count. A total that does not state its scope and data confidence is just a number.

The aim of the first year is not to produce a flawless inventory but to set up a working method. Missing fields are marked, estimates are noted as estimates, and the areas to improve in each period are listed. This approach makes it possible in the second year to extend the same flow instead of compiling the data again.

Karbonİz’s control tower combines Scope 1, 2 and 3 visibility with targets, data confidence and hotspots on the same screen. ERP, energy meters, e-invoice, logistics and supplier PCF data are brought into a common flow; every result is traceable to the source record, factor version, evidence and approval status. So you see together how much each scope’s total affects the whole and how solid that figure is; a manager can decide from this view where to direct the data collection effort.

You can read about our approach to collecting carbon data, calculating it traceably and linking it to reduction decisions on the Carbon Footprint page.