Motorcycle generic Defra

This category allows users to calculate greenhouse gas emissions from a motorcycle journey from indicating the motorcycle fuel and size. The methodology follows the latest Defra emission factors and advice.

How to use this category

There are two drill-downs in this category. For the first drill, fuel, there is currently just one option - petrol. The second drill-down, size is used to select the size of the motorcycle from the following list.

• small (<125cc)

• medium (125-500cc)

• large (>500cc)

• unknown - for use if motorcycle size is unknown

The occupants profile item value is used to enter the number of people in the car for the selected journey (default 1). The emissions are then divided by the number of occupants in order to return the fraction of the emissions due to each person. The ownFuelConsumption can be entered if the user has a reliable value for their vehicles fuel consumption (default units of km/L). If this is entered then it overrides CarbonKit's default emission factors for the selected vehicle. The algorithm then divides the fuel emission factor, from the Fuel_Defra category, by the users ownFuelConsumption and multiplies by the distance. The /numberOfJourneys profile item value (default 1) can be used if the specified journey has been repeated a number of times; the emissions for one journey are multiplied by this value. Finally, totalFuelConsumed can be entered if the volume of fuel used for the entire journey is known. In this case the volume of fuel is multiplied by the appropriate emission factor in the Fuel_Defra category.

Algorithm

If no fuel consumption data is entered

CO2eEmissionFactor = CO2EF + CO2eEFForN2O + CO2eEFForCH4

CO2e = CO2eEmissionFactor * distance / occupants

If ownFuelConsumption entered

CO2eEmissionFactor from business/energy/fuel

CO2e = (CO2eEmissionFactor / ownFuelConsumption) * (distance / occupants)

If totalFuelConsumed entered

CO2eEmissionFactor from business/energy/fuel

CO2e = CO2eEmissionFactor * totalFuelConsumed

The algorithm returns a value of kgCO₂e for the particular journey, per occupant. This value includes contributions from carbon dioxide, nitrous oxide and methane.