Influence of excavator mass on CO ₂ emissions and energy consumption during biomass stacking

Woodchips can be produced by comminution of biomass harvested in dedicated plantations, in forests, and from wood residues such as tops, branches, and stumps. The stacking of the biomass to be chipped can be done with an excavator. Construction machinery manufacturers developed various kinds of machines, diesel-hybrid, and fully electric, but electric versions of large machinery used in forestry would be out of reach of any charging infrastructure. This work aimed to determine the effect of technical characteristics of excavators used in the stacking of biomass, on energy consumption and CO2eq emissions to reduce environmental impacts in the form of energy consumption and CO2eq emissions. Fuel consumption ranged between 6.7 l h−1 and 17.5 l h−1, with two indicative values of fuel consumption calculated for the excavator per kW of nominal power and per t of gross mass of the excavators: 0.14 l h−1 × kW and 0.72 l h−1 × t of gross mass. The energy consumption per unit of biomass produced varied from 44.73 MJ t−1 to 67.78 MJ t−1. The CO2eq emission ranged between 5.44 kg CO2eq× t of biomass handled and 7.77 kg CO2eq× t of biomass handled. In the trials performed and in the test conditions, working with an excavator that is appropriately sized for the type of assortment to be handled can improve the productivity of the work, reducing the environmental impact as CO2eq emissions can be reduced by at least 14% and energy consumption can be reduced.