Energetic and Socioeconomic Justification for Solar-Powered Desalination Technology for Rural Indian Villages

Abstract

This paper provides justification for solar-powered electrodialysis desalination systems for rural Indian villages. It is estimated that 11% of India’s 800 million people living in rural areas do not have access to an improved water source. If the source’s quality in regards to biological, chemical, or physical contaminants is also considered, this percentage is even higher. User interviews conducted by the authors and in literature reveal that users judge the quality of their water source based on its aesthetic quality (taste, odor, and temperature). Seventy-three percent of Indian villages rely on groundwater as their primary drinking supply. However, saline groundwater underlies approximately 60% of the land area in India. Desalination is necessary in order to improve the aesthetics of this water (by reducing salinity below the taste threshold) and remove contaminants that cause health risks. Both technical and socioeconomic factors were considered to identify the critical design requirements for inland water desalination in India. An off-grid power system is among those requirements due to the lack of grid access or intermittent supply, problems faced by half of Indian villages. The same regions in India that have high groundwater salinity also have the advantage of high solar potential, making solar a primary candidate. Within the salinity range of groundwater found in inland India, electrodialysis would substantially reduce the energy consumption to desalinate compared to reverse osmosis, which is the standard technology used for village-level systems. This energy savings leads to a smaller solar array required for electrodialysis systems, translating to reduced capital costs.