Coupling irrigation scheduling with solar energy production in a smart irrigation management system

Abstract

In recent years, pressurized pipe networks have improved the efficiency of irrigation systems while substantially increasing their energy demand. The progressive rise in energy costs makes it difficult to maintain the profitability of agricultural holdings. Moreover, global warming is a serious problem that threatens the environment worldwide and low CO2 emission processes should be promoted. To address these issues, it is necessary to look for sustainable and more profitable alternatives for the agricultural sector. One of these new alternatives is the use of renewable energies for pumping irrigation water at farm level, particularly photovoltaic energy. Nevertheless, the instability of irradiation hinders its management for stand-alone photovoltaic installations. In this work, a real-time model called the Smart Photovoltaic Irrigation Manager (SPIM) is developed to synchronize the photovoltaic power availability with the energy required to pump the irrigation requirements of different sectors of irrigation networks. SPIM consists of different modules to calculate the key management variables of the photovoltaic irrigation system: the daily irrigation requirements, the hydraulic behavior of the irrigation network, the instantaneous photovoltaic power production and the daily soil water balance. The lack of photovoltaic energy during daylight hours on any day of the irrigation season to supply the daily required amount of water is balanced with either the water stored in the soil or by extending the duration of the irrigation events in the following days when necessary. SPIM has been applied to simulate the management of photovoltaic irrigation in a real olive orchard in Southern Spain during the 2013 irrigation season. The results showed that the proper management of the photovoltaic irrigation system provided enough water to satisfy crop irrigation requirements throughout the irrigation season and avoided the emission of 1.2 tn CO2 eq using only the energy generated by solar panels.