Feasibility Evaluation of Hybrid Electric Agricultural Tractors Based on Life Cycle Cost Analysis

Abstract

In recent years electrification of agricultural machinery vehicles is gaining interest from the manufacturers point of view to meet the emission reduction targets set by several authorities. Some studies have already investigated the topic, however, none of them have dealt with the challenges of agricultural machinery electrification in a general and methodical way. 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.

Simulation-Based Assessment of Energy Consumption of Alternative Powertrains in Agricultural Tractors

“…The results indicate that the parallel hybrid electric powertrain would provide meaningful energy savings for medium-sized tractors and, when operating with lighter loads, large-sized tractors. Similar conclusions were drawn in recent research by Beligoj et al ( 2022), who evaluated the feasibility and life-cycle cost of a parallel hybrid powertrain for different sizes of agricultural tractors [35]. They concluded that very little energy consumption reduction or cost saving would be attained with large-sized tractor (engine power of 210 kW) hybridization, but small-sized orchard tractors and medium-…”

“…Nevertheless, more detailed simulations should be performed to evaluate the potential of the series hybrid powertrain for different types of agricultural tasks. In comparison to parallel hybrid powertrains, the series hybrid powertrain could provide the possibility of using the electric power take-off (ePTO) and electrified implements, which would be much harder to accomplish with the parallel hybrid due to the limited amount of on-board electric power [35].…”

Electric autonomous tractors in Swedish agriculture : A systems analysis of economic, environmental and performance effects

“…Hybrid tractors with both electric and ICE drivelines (parallel and series hybrids) have been researched, but have been found to be insufficiently profitable to take a large market share (Lajunen et al, 2018;. The low profitability is because the increased component costs with hybrid tractors exceed any fuel savings enabled by the regenerative braking and reduction in fuel use (Beligoj et al, 2022;Lajunen et al, 2018). Generally, hybrid vehicles are a good solution when there are frequent changes in engine speeds, where the higher efficiency of the motor can improve fuel economy, and where there is a good amount of braking, to regenerate energy (Grunditz, 2016).…”

“…Alternatively, several tractors and/or drivers could be hired or a very large battery could be used, which again would lead to high costs. In order for electric tractor systems to be successful, these challenges need to be resolved (Beligoj et al, 2022).…”

Carbon Footprint of an Orchard Tractor through a Life-Cycle Assessment Approach

“…The first step was the definition of a reference duty cycle. Belog et al [45] The fuel consumption data for the first two kinds of operations were empirically col lected from the tractor. The measurements were conducted with an Antonio Carraro TRG 10900 (Figure 2) equipped with a Kubota V3800DI-T-E3B ICE (Table 11).…”