The basis for large goods emissions calculations
Since large goods vehicles are typically used for the freighting of goods, an important distinction can be made between the calculation methodologies available within this category.
Emissions by distance
Some methodologies estimate emissions on the basis of distance travelled only. In this case, calculations are made on the basis of distance-based emissions factors (e.g. kg CO2 per km), and users are therefore only required to specify a distance value. The returned value implicitly represents emissions for an entire vehicle journey(s), i.e. on a per vehicle basis. In these cases, large goods vehicles are treated similarly to other vehicles such as cars or motorcycles.
Emissions by distance and mass
Other methodologies use data relating to the fuel consumption of freighting vehicles together with assumptions regarding their typical freight loading to establish emissions factors which describe emissions according to a specific unit of freight transported. These emissions factors are of the form mass CO2 per distance per mass (e.g. kg CO2 per km per tonne) and therefore require both a distance and a value for the mass of the freight transported to be specified in order for a calculation to be made. In these cases, the value returned represents only the emissions attributable to the quantity of freight specified, rather than the full vehicle journey.
Large goods methodologies available through CarbonKit
Heavy goods - DEFRA
The DEFRA heavy goods vehicles category contains the most recently published DEFRA data on greenhouse gas emissions associated with representative lorry types in UK. The methodology uses distance-based, per vehicle emissions factors, requiring the user to specify the distance travelled. This category includes CO2, CH4 and N2O emissions as part of each calculation users may also specify the percentage loading of lorries for a more accurate emissions calculation.
Generic car transport - IPCC
The IPCC large goods transport category contains data on lorry-associated emissions sourced from the IPCC Guidelines for National Greenhouse Gas Inventories. This category contains data and methodologies for European and US contexts and calculates emissions on per vehicle basis, using fuel consumption or a combination of fuel consumption, fuel efficiency and distance. Vehicle types are organised according to fuel type and emissions control technology.
Generic car transport - GHG Protocol
The GHGP large goods vehicle category contains data on lorry-associated emissions sourced from the latest World Resources Institute Greenhouse Gas Protocol (GHGP) documentation. This category includes emissions methodologies for transport in several geographic contexts, with vehicle types organised according to fuel type.
Several freight-based emissions methodologies (i.e. based on distance and mass) can be accessed via the Road freighting subcategory, which includes data and methodologies sourced from the World Resources Institute Greenhouse Gas Protocol (GHGP) and DEFRA the UK government agency.