Scope 3 Category 3: How to calculate fuel and energy-related emissions
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Scope 3 Category 3 covers upstream fuel and energy-related emissions that have not already been accounted for within those two scopes. These can include emissions associated with producing and transporting purchased fuels, generating purchased energy and losses across electricity networks.
Calculating these emissions helps businesses understand the wider environmental impact of their energy consumption and build a more complete carbon footprint.
Scope 3 Category 3 covers indirect emissions associated with the fuel and energy a business purchases and consumes.
These emissions occur outside the organisation's direct operations and are not already included in its Scope 1 or Scope 2 calculations.
For example, burning natural gas in a company-controlled boiler produces direct Scope 1 emissions. However, extracting, processing and transporting that gas before it reaches the business also generates emissions.
Those upstream activities can fall within Scope 3 Category 3.
The category helps businesses understand the environmental impact of their energy use beyond the point of consumption.
There are four main activities that can fall within Scope 3 Category 3:
The fourth activity will not apply to most businesses.
Organisations should identify which activities are relevant to their operations before gathering data.
The distinction comes down to which stage of energy production or consumption generates the emissions.
Scope 1 covers direct emissions from sources a business owns or controls, such as fuel burned in company-controlled boilers or vehicles.
Scope 2 covers indirect emissions associated with purchased electricity, steam, heating and cooling consumed by the organisation.
Category 3 captures relevant upstream fuel and energy-related emissions that sit outside those calculations.
For example, a business purchasing natural gas may report the emissions from burning that gas under Scope 1 and the upstream emissions associated with supplying it under Scope 3 Category 3.
The same fuel consumption records can support both calculations, but different emissions factors are required.
Most businesses can begin with energy information they already collect.
Useful records include:
Green Economy recommends gathering reliable activity data across a consistent reporting period.
Businesses should check that records cover all relevant sites and activities and identify missing information before starting calculations.
The basic calculation involves multiplying the quantity of fuel or energy consumed by an appropriate emissions factor.
Category 3 emissions = energy or fuel consumed × relevant upstream emissions factor
However, Category 3 contains different emissions sources, so businesses should calculate each applicable activity separately.
The factor selected must represent the emissions being measured rather than simply repeating the factor used for Scope 1 or Scope 2.
For UK businesses, the government's greenhouse gas conversion factors can provide relevant information for calculating fuel and energy-related emissions.
Businesses should use factors appropriate to their reporting year, activity and calculation methodology.
Upstream fuel emissions arise before the fuel is burned.
They can include emissions from extraction, processing, refining and transportation.
For example, a business may purchase diesel for company-controlled vehicles.
The direct emissions from burning that diesel are generally reported under Scope 1. The upstream emissions associated with producing and supplying it can be reported under Category 3.
To calculate these emissions, the business needs the quantity of diesel consumed and an appropriate upstream fuel emissions factor.
The factor must exclude the combustion emissions already accounted for elsewhere.
Electricity generation can involve upstream emissions associated with extracting, processing and transporting the fuels used at power stations.
These upstream emissions are separate from the generation emissions accounted for under Scope 2.
Businesses can calculate this part of Category 3 using their purchased electricity consumption and an appropriate upstream electricity emissions factor.
For example, electricity consumption recorded in kWh can be multiplied by the relevant upstream factor to estimate the associated emissions.
The calculation should reflect the reporting methodology used and avoid including emissions already captured within Scope 2.
Some electricity is lost while travelling through transmission and distribution networks.
The generation of electricity that is lost in this way creates emissions that can fall within Category 3 for the end user.
Businesses can estimate these emissions using electricity consumption data and appropriate transmission and distribution loss factors.
The calculation should distinguish these losses from the electricity consumption already accounted for under Scope 2.
Where published conversion factors are used, businesses should check what each factor includes before applying it.
Consider a business that consumes 100,000 kWh of purchased electricity during its reporting year.
For illustration, assume the applicable upstream electricity emissions factor is 0.04 kg CO2e per kWh.
The calculation would be:
100,000 kWh × 0.04 kg CO2e/kWh = 4,000 kg CO2e
This equals 4 tonnes of CO2e associated with the upstream electricity activity represented by that factor.
The 0.04 figure is hypothetical and should not be used as an actual reporting factor.
The business would calculate relevant transmission and distribution loss emissions separately using the appropriate factor or methodology.
This example demonstrates the calculation process rather than providing a complete Category 3 footprint.
Double counting is a particular risk when calculating Category 3 because the same energy consumption records may also be used for Scope 1 and Scope 2.
Businesses should check which emissions are already included in their existing footprint.
For example, an emissions factor covering both fuel combustion and upstream production should not be applied in full to Category 3 if combustion emissions have already been reported under Scope 1.
Similarly, electricity-related factors should be reviewed to ensure they capture the intended upstream activity without duplicating Scope 2 emissions.
Documenting the factors, data sources and category boundaries used makes the calculation easier to review.
The most appropriate factor depends on the fuel or energy source and the reporting methodology.
For UK organisations, the government's annual greenhouse gas conversion factors provide information that can support calculations for purchased fuels, electricity and related upstream activities.
Businesses should select factors that match:
Where supplier-specific information is available, it may help improve the representativeness of the calculation.
Using consistent, clearly documented factors is important when comparing results between reporting periods.
Missing energy records can affect the reliability of a Category 3 calculation.
Businesses should first review existing invoices, meter readings and fuel purchasing information to identify gaps.
Where records cannot be recovered, reasonable estimates may be necessary, provided the assumptions and calculation methods are documented.
For organisations operating across several sites, it is important to check whether all relevant premises and activities have been included.
Improving the completeness of existing Scope 1 and Scope 2 activity data can also strengthen Category 3 reporting because the calculations often rely on the same underlying consumption figures.
Category 3 helps businesses understand the wider emissions associated with their fuel and energy consumption.
Once these emissions have been calculated, organisations can consider them alongside Scope 1 and Scope 2 when reviewing energy-related carbon reduction opportunities.
Potential measures include:
The impact of each measure will depend on the organisation's energy use and the emissions factors applied.
Businesses should assess actual consumption changes and associated emissions rather than assuming that every efficiency improvement produces the same carbon savings.
Businesses should measure Category 3 emissions consistently across their chosen reporting periods.
Annual calculations can help organisations monitor changes in energy consumption and the associated upstream emissions.
However, changes in emissions factors can also influence the reported results.
For example, electricity-related factors may change between reporting years even where consumption remains similar.
Businesses should document changes in methodology, activity data and emissions factors so that reported reductions can be interpreted accurately.
Green Economy's carbon footprinting support helps businesses measure Scope 1, Scope 2 and Scope 3 emissions, establish reliable baselines and identify opportunities for carbon reduction.
Its guide to measuring Scope 3 emissions provides further information on understanding indirect emissions and collecting relevant activity data.
Businesses can also explore Green Economy's guidance on calculating a business carbon footprint to understand how energy records and emissions factors contribute to wider carbon reporting.
Green Economy's broader decarbonisation support helps organisations identify practical opportunities to improve efficiency, reduce emissions and develop their sustainability strategies.
Contact Green Economy to discuss how its carbon footprinting and sustainability consultancy services could support your organisation's reporting and carbon reduction objectives.
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