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

Matteo Beligoj,Michele Mattetti,Elia Scolaro,Luigi Alberti,Massimiliano Renzi

doi:10.1109/access.2022.3157635

Abstract

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.

Highlights

Nowadays, global warming and carbon dioxide (CO2) concentration in the atmosphere represent critical problems
The maximum power region at high speed is one of the worst conditions in terms of exhaust emissions, but this region is often exploited in agriculture operations [3]
The purpose of this paper is to provide a method to evaluate the economic feasibility of farming tractor powertrain electrification through a simplified Life Cycle Cost (LCC) analysis, and, at the same time, to determine the best Internal Combustion Engines (ICEs) downsizing in the case of a parallel hybrid electric configuration

Summary

Introduction

Global warming and carbon dioxide (CO2) concentration in the atmosphere represent critical problems. The agriculture and forestry sectors were among the main contributors to global greenhouse gas emissions in 2017, with a contribution of 20% of the equivalent carbon dioxide emissions [1]. Whereas the larger part of this pollution is related to intensive animal farming and ground working, a considerable amount comes from exhaust gas of Internal Combustion Engines (ICEs), which are the most widespread power sources in agriculture and forestry industry. Exhaust gas emissions are critical when diesel. The maximum power region at high speed is one of the worst conditions in terms of exhaust emissions, but this region is often exploited in agriculture operations [3]. In tractors’ working cycles, idling conditions have a relevant contribution in terms of environmental impact and engine life, without contributing to the effective required work [4], [5]

Objectives

Methods

Results