Techno-economical Comparison of MED and RO Seawater Desalination in a Large Power and Water Cogeneration Plant in Iran

Seawater desalination is one of the major solutions to overcome water crisis in MENA region. In this paper, two main scenarios have been studied for desalting seawater from the source of the Persian Gulf. First scenario is based on two 170 MW gas turbines, one 160 MW steam turbine and 143,000 m(3)/day MED thermal desalination, while the second plant is based on two 170 MW gas turbines, one 95 MW steam turbine and 143,000 m(3)/day SWRO membrane desalination. Technical and economical modeling of each scenario has been done and their levelized water costs have been compared. Results show that levelized water cost in cogeneration plant with membrane desalination is lower than cogeneration plant with thermal desalination in the range of 0 (Energy conversion agreement) to 30 $cent/m(3) for fuel price. For Persian Gulf FOB gas price of 8.6 $cent/m(3), MED water cost is 1.16 $/m(3) and SWRO water cost is 0.99 $/m(3). Sensitivity analysis has been done for a range of availability in power and water production, years of operation, and capital cost margin.