Abstract
This study will investigate the exergy, power consumption and economic analysis of two desalination plant techniques in Waddan City in Libya to find the optimal selection of desalination technique can be used in this area, where the source of brackish water is available. The geothermal water was used to power the single effect desalination plant and electrical power for single pass reverse osmosis. The results showed that as the feed water temperature increased the exergy efficiency of both techniques increased where the reverse osmosis is higher than single effect by about 95%, the specific power consumption of Single-reverse osmosis is lower than single-effect desalination plant by about 50%. Also the economic analysis showed that single effect desalination life water cost is higher than single-pass reverse osmosis by about 38%, where the payback period dependent on the water selling price and the single-pass reverse osmosis has lower payback period