Embodied energy associated with the materials used in irrigation systems: drip and centre pivot

Abstract

Evaluations able to estimate sustainability indices of production systems have intensified the use of complex analysis. The energy flow methodology considers the total direct and indirect energy required by production systems. A way to determine energy flows is through material flow determination, which is used as a material inventory of processes. This study aimed to define a model to determine the indirect embodied energy for two kinds of irrigation systems, drip and centre pivot, whose variables are parameters of irrigation projects such as irrigated area, distance between irrigation assets and water source, and useful life of the equipment. Using the same scenario presented by other authors to compare the values of indirect embodied energy for centre pivot irrigation, the model results ranged from 4.10 to 2.09 GJ ha−1, where the highest value is a result of using just 10 years for the centre pivot useful life. For drip irrigation system, the indirect embodied energy ranged from 5.52 to 6.20 GJ ha−1. The participation of each part of the system differs between the scenarios evaluated. The pump system was responsible for between 0.38 and 3.14%, the filter systems had a minute share for the drip system (<0.01%), the pipeline ranged from 0 to 23% and the internal part of the irrigation systems was the most important and ranged from 75.34 to 99.62%. The model developed can be used to identify the indirect embodied energy in analysis of irrigated production systems in different project conditions.