Energy, water and material footprints of agricultural machinery industry

Abstract

The intensification of agricultural production systems demand power, supplied by agricultural machinery, besides more agricultural inputs such as fertilizer, pesticides and seeds. Agricultural mechanization provided increase in the global production of food, fiber and bioenergy; and it brought economic benefits to producers, but causing larger energy consumption. Energy embodiment in agricultural machinery has been approached, but data usually are from car industry. This study aimed to determine the energy demand in a plant that assembles five types of agricultural machinery from a multinational manufacturer located in Piracicaba municipality in Sao Paulo state, Brazil. That plant assembles two types of sugarcane harvester, coffee harvesters, sprayers and planters. Inputs taken into account were classified as direct (electricity, LPG, water etc.) and depreciated inputs (infrastructure, tools etc.), regarding how they are consumed over time. Data about the physical demand were determined, providing the material flows, which were used to estimate the energy and water flows by multiplying them by their respective energy embodiment and water footprint indices. Electricity accounts for the highest share (88.9%) in the total energy demand. From depreciated inputs, buildings accounted for almost the full embodied energy, but this category had a minute participation on the total energy (<2.5%). The industrial assembling requires on average 13.5 GJ of energy and 34.8 m³ of water per machine assembled. While labor accounts for two thirds of the average water footprint per machine produced, its embodied energy was very small, thus can simply be neglected from the energy analysis. The indirect water footprint related to depreciated inputs is very minor and can be neglected without affecting the final result. The direct water demand was from 5.6 to 15.7 m³ per machine compared to the average indirect water footprint of 23.7 m³. In terms of per unit mass of assembled machine, the embodied energy demand varied from 1.22 to 2.36 MJ kg^-1 and the water footprint varied from 3.27 to 6.27 L kg^-1