Transport fuels with context by Greenhouse Gas Protocol

Summary

This methodology represents greenhouse gas emissions associated with the combustion of fuel in specific transportation contexts in the US, UK and other regions. The data and calculation methodology is based on those provided in the Greenhouse Gas Protocol worksheet GHG emissions from transport or mobile sources (version 2.2), published in June 2011.

The methodology

Emissions model

The emissions methodology is based upon emissions factors which describe the greenhouse gas emissions associated with the specific quantities of transport fuel. These emissions factors can be contrasted with similar transport-related emissions factors which describe emissions on the basis of distance. This methodology is typically more accurate for calculating transport related greenhouse gas emissions since it involves a more direct measure of fuel consumption without the requirement for assumptions about vehicle fuel efficiencies.

According to this methodology, CO₂ emissions are directly related to the quantity of carbon which is oxidised during combustion and therefore directly proportionate to the quantity of fuel burned and the concentration of carbon within the particular fuel type (e.g. gasoline/petrol, diesel). Emissions of CH₄ and N₂O, however, are considered to vary with the specific use context. This category, then, provides fuel-based emissions factors for CH₄ and N₂O differentiated by fuel type and specific use contexts. For a complete greenhouse gas calculation, CO₂ emissions factors referenced for each fuel type from this related methodology, sourced from the same Greenhouse Gas Protocol worksheet.

Emissions - conventionally expressed in terms of mass (e.g. kg) - are calculated by multiplying these rates (mass emitted per volume; e.g. kg CO₂ per US gallon) by a volume of fuel (e.g gallons) consumed.

Model data

The rate at which fuel combustion produces greenhouse gas emissions varies depending on fuel type and the specific use context. Therefore, emissions factors for distinct combinations of fuel type and context are provided. The fuels represented are:

• diesel
• petrol/gasoline
• residual fuel oil

• train
• agricultural equipment
• construction equipment
• ship and boat

Activity data required

According to this methodology, greenhouse gas emissions are directly proportionate to the quantity of fuel consumed. Fuel quantity must be specified on the basis of volume by setting the volume profile item value.

Users can choose to specify their activity data in a comprehensive range of appropriate units.

Calculation and result

The returned quantities for this methodology represent CO₂, CH₄ and N₂O and CO₂e emissions associated with the type, quantity and context of fuel specified. CO₂e emissions represent all three gases, converted using these global warming potential). The individual quantities for CH₄ and N₂O represent absolute quantities rather than CO₂e quantities.

Similar methodologies

Other Greenhouse Gas Protocol transport methodologies are available representing general fuel consumption, freighting of goods, passenger/public transport, and road transportation in the UK (with heavy goods), US and other regions.