Optimum operation of desalination plant to minimize power consumption and water shortage risks in Okinawa, Japan

Abstract

ABSTRACT Okinawa Island is located in the southern region of Japan and has a population of 1.22 million. Okinawa Prefectural Enterprise Bureau (OPEB) supplies 410,000 m3/d of water to 24 municipalities. Although OPEB uses multiple water resources including dam reservoirs and groundwater, increased water demand resulted in occasional water shortages until a seawater desalination plant (40,000 m3/d) started operations in 1997. In this study, a model was developed to simulate the water supply system of Okinawa Island using precipitation and OPEB operational data from 2009 to evaluate the role of the desalination plant in reducing risks associated with drought and power consumption of the plant. The simulation results indicate that without the desalination plant, the dam reservoir storage falls below 50% for 70 days, whereas with the desalination plant, storage remains above 50%. If the plant was operated at full capacity, the dam reservoir storage increased by 17.2% after 1 year of simulation time. However, ...