Summary of machinery boundary
Overview
Machinery use activities calculate emissions due primarily to fuel combustion in service of production of the measured. This included activities performed on the field for the full cultivation cycle.
The primary parameter impacting the emissions in this activity is fuel consumed by machines while operating on the field.
Fuel used is assumed to always be diesel.
Full boundary of machinery emissions
Emission factors used are from Ecoinvent which accounts for assumptions of fuel used for the type of machinery used, and the time required to perform the activity per ha. There are assumptions of a small portion of emissions attributed to a shed for the equipment but this is a small portion of the overall emissions coefficient.
Each Ecoinvent machine boundary from their activity methodology is:
“The dataset includes the diesel fuel consumption and the amount of agricultural machinery and of the shed, which has to be attributed to the process. Also taken into consideration is the amount of emissions to the air from combustion and the emission to the soil from tyre abrasion during the work process. The following activities were considered part of the work process: preliminary work at the farm, like attaching the adequate machine to the tractor; transfer to field (with an assumed distance of 1 km); field work (for a parcel of land of 1 ha surface); transfer to farm and concluding work, like uncoupling the machine.” -Ecoinvent v3.11
Fuel consumption
Diesel consumption is the most crucial parameter in this activity’s outcomes. In this methodology and that consumption amount is assumed within the emission factor coefficient used.
However, fuel consumption linearly affects direct emissions generated. So in cases where primary data of fuel consumption is known, Ecoinvent advises that the user can adjust the per hectare assumption of this activity to the known fuel used. For example: If you know your diesel consumption is three times as much as assumed from Ecoinvent (1 kg/ha) then the user can just assume 3 ha instead.