Feasibility and Design of Solar-Powered Electrodialysis Systems for Agriculture Applications

Abstract

This paper presents photovoltaic-powered electrodialysis reversal (PV-EDR) as a promising desalination technology for agricultural applications in the Middle East and North Africa (MENA). Water scarcity in MENA has led to reliance on brackish water for irrigation of crops. Irrigating crops with high salinity water causes a host of problems including decreased yield and soil degradation. Current solutions are water and energy intensive, leading to overextraction of renewable water resources as well as overreliance on fossil fuels for electricity, which is expensive. Market research in MENA and interviews conducted with farmers in Jordan led to the conclusion that energy cost is the most significant issue facing small-scale desalination systems for agriculture in MENA. PV-EDR is chosen as an ideal desalination architecture to meet the needs of farmers by reducing energy costs compared to on-grid reverse osmosis (RO) systems that are currently employed in MENA. Time-variant (TV) operational theory for PV-EDR is presented, which allows for desalination production to match the available solar irradiance throughout a day, leading to decreased power system sizing and further cost savings. TV-PV-EDR can be integrated with waterand energy-efficient drip irrigation systems in order to tailor desalination production to crop water demand throughout a season. Given a case study in Jordan, a TV-PVEDR system is designed and compared to current benchmark RO systems in relation to capital cost, energy cost, and total lifetime cost. TV-PV-EDR was found to be less expensive and more energy efficient than RO systems over its lifetime despite having a larger capital cost. TV-PV-EDR has the potential to provide a mechanism through which more energy-efficient, higher recovery desalination for agriculture can be achieved.