Scope 3 Category 11: Calculation and Worked Example

Scope 3 Category 11 measures emissions from customers using products sold in the reporting year, across those products' expected lives. This guide explains the boundary, the calculation and the evidence to collect before commissioning a use-phase model.

What belongs in Category 11?

A manufacturer's factory energy and a customer's product-use energy answer different questions. Category 11 is downstream of the sale. Keep manufacture, distribution, customer processing and disposal in their appropriate inventory categories rather than treating this as a whole product footprint. The Scope 3 Standard provides the broader category framework.

Direct and indirect use-phase emissions: the important distinction

In Category 11 terminology, products that consume electricity or fuel themselves have direct use-phase emissions. This includes electric appliances. Indirect use-phase emissions arise from activities associated with using a product, such as washing clothing. Direct use is included in the minimum boundary; indirect use is optional and should be considered when significant. This distinction is different from whether the seller owns the emission source. See GHG Protocol's Category 11 guidance, table 11.1.

Calculation formula and reporting period

For a simple electricity-consuming product group, multiply units sold by lifetime electricity use per unit and the electricity emission factor. Repeat for other product groups and relevant fuels or gas releases. The example below isolates electricity; it is not a complete inventory. Sales belong to the reporting period, while expected use extends across product life.

A worked example: 200 electric appliances

All numbers below are invented for explanation. They are not a client's results, a benchmark or a recommended emission factor.

200 × 300 × 8 × 0.40 = 192,000 kg CO₂e = 192 tCO₂e.

First, each appliance uses 2,400 kWh over eight years. The sales cohort therefore uses 480,000 kWh. Applying the assumed factor produces the result above. Counting only one year would produce 24 tCO₂e, which would describe a different time boundary.

As an original sensitivity check, changing the assumed lifetime to six years gives 144 tCO₂e; changing it to ten gives 240 tCO₂e. These are alternative assumptions, not a statistical confidence interval. The example keeps consumption and the factor constant solely to make the arithmetic visible. A real model needs representative usage and documented factor choices. Do not use a warranty period as a lifetime estimate without justification.

An evidence checklist for your first review

For a practical scoping conversation, we recommend preparing the following. You do not need to email confidential records before an appropriate transfer method is agreed.

• A reporting-year sales extract by product group, with returns and exclusions explained.
• Product specifications and the evidence behind normal operating consumption.
• Use-pattern and lifetime assumptions, with a named source and reviewer.
• A sales-region breakdown and a record of selected emission factors, units and versions.
• A list of unmodelled products, uncertain downstream uses and unresolved data gaps.
• The intended audience: an internal decision, a customer request or a reporting requirement.

Our recommended working file has one row per product group or justified use scenario. Give every assumption a source, an owner and a review date. Make conversions visible so another reviewer can follow the result without reconstructing the model.

What if you sell components rather than final products?

Do not automatically assign the entire final product's use-phase footprint to one component. GHG Protocol's intermediate-product guidance distinguishes the sold intermediate product from the final product. Uncertain downstream applications require a documented boundary decision; uncertainty is not a reason to silently record zero.

Can avoided emissions reduce the reported total?

No. A claim that a product replaces a higher-emission alternative is a separate comparison. Do not deduct that estimated benefit from Category 11. GHG Protocol requires avoided-emissions reporting to be separate from the inventory, with its comparison method and assumptions disclosed. See its avoided-emissions guidance.

For product-development discussions, test efficiency and usage scenarios using the same boundaries. A longer product life can increase this sales cohort's estimated lifetime electricity even when durability has other benefits. Avoid turning a single scenario into an unqualified environmental claim.

Questions before you start