Design of power systems for reverse osmosis desalination in remote communities

Many remote communities lack access to a reliable water supply. They often have access to brackish groundwater or seawater, making reverse osmosis desalination a possible solution. However, reverse osmosis desalination is an energy-intensive process and many remote communities are off the electrical grid. Determining the most economic reverse osmosis system configuration and electrical power source for a given remote community is a challenge due to their unique resource availabilities. This paper presents an optimization-based approach to compare the economics of different small-scale reverse osmosis systems and power sources for remote communities. In this approach, physical models describe the performance of electrical power systems composed of photovoltaics, wind turbines, diesel generators, batteries, and hybrid systems. These power system models are coupled to a reverse osmosis system model to determine the water production. An optimization is performed to determine the most economic power system configuration, reverse osmosis system size, and water storage size that meets the desired water production reliability. The reliability is expressed as loss of water probability, which is computed using hourly environmental data. Here, this method is used to configure a reverse osmosis system for small communities. Results are presented for locations in Honduras, Eritrea, and Australia. Results show that the local climatic conditions greatly influence the economic attractiveness of different technologies. The variety of solutions found using this approach demonstrate the ability of the method to aid in the design of a power system and reverse osmosis system configuration for any location.