Today, agriculture industry has a significant impact in global greenhouse gas emissions. A large amount of pollutants come from diesel internal combustion engines, widely used in agricultural machinery. Since mechanization in agriculture is fundamental to achieve a proper food production for a growing human population, changes are needed in common agriculture engineering thinking in order to develop new farming machinery that could outperform conventional ones in terms of environmental impact, as well as performance, productivity and safety. Electrification is a feasible solution. A comprehensive review about agricultural machinery electrification is reported in this paper, with a particular focus on hybrid electric tractors and their implements. The introduction of electric drives in farming tractors is discussed in detail by looking at the main findings in literature and considering state-of-the-art technology. Proposals and prototypes from manufacturers are covered too, as well as economic assessments and future trends.

This paper presents a method to evaluate the economic feasibility of tractor powertrain electrification based on life cycle cost analysis. For a parallel hybrid, the best combustion engine downsizing, among some discrete values, was evaluated. The methodology was applied to three case studies with different power levels and operating cycles: a 76 kW orchard tractor, a 175 kW row crop tractor with medium duty use, and a 210 kW row crop tractor with heavy duty use. Fuel and electrical energy consumption were estimated through simulation. A range of powertrain components prices and fuel and electrical energy prices was taken into account, in order to cover price uncertainty and to show its effects. The results show that operating cost savings decrease when more power-intensive operations are performed. Considering a combination of system and energy prices deemed realistic by the authors, the operating cost savings, respectively for orchard, row crop medium duty, and row crop heavy duty, are approximately 8%, 3%, and 0.5%, which result in 6%, 1%, and 0.1% life cycle cost savings. Thus, powertrain electrification of high-power tractors should probably be avoided, whereas it could be beneficial for specialized orchard tractors. The developed method has proved to be suitable for such analyses.

This paper presents a quasi-static model for assessing potential energy savings through partial electrification of a land leveler implement. The quasi-static model simulates the behavior of the hydraulic circuit components, including the pump and a spool-type flow divider, for a commercial land leveler used in agricultural applications. Two electrification schemes are presented. In the first scheme, the pump, originally driven at fixed speed by the PTO, is driven at variable speed by an electric drive, with no changes in the hydraulic circuit. In the second electrification scheme, the decentralization of the hydraulic system is implemented by using separate variable-speed pumps for each actuator. Results show significant potential energy savings of 9–22% with the first electrification scheme and 45–53% with the second scheme, compared to the traditional non-electrified setup. Our findings demonstrate that electrification could be a strategic choice to improve the efficiency of tractor implements and agricultural machinery.