Preliminary thermoeconomic analysis of combined parabolic trough solar power and desalination plant in port Safaga (Egypt)

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The development of society is strongly dependent on water and electricity. There is an increasing water and energy demand driven by population growth and rising industrial and agricultural production. The combination of concentrated solar power (CSP) and desalination processes has a huge potential for producing both energy and water in arid regions suffering from fresh water scarcity and facing the current energy challenge. One of the regions is Middle East and North Africa (MENA), where plans are currently under discussion to make possible large CSP plants developments. The integration of desalination (CSP+D) into solar power plants could make CSP technology even more attractive in such regions. The focus of this study is thermodynamic characterization and an economic evaluation of different configurations for coupling parabolic trough solar power plants and desalination facilities at a MENA location in Egypt chosen as reference for its Southern coast (Port Safaga). The desalination technologies considered for the combination with parabolic trough concentrating solar power plants (PT-CSP), are low temperature multi-effect distillation (LT-MED) and reverse osmosis (RO). Moreover, an additional concept of LT-MED has been evaluated: a LT-MED powered by the steam obtained from a thermal vapor compressor (TVC). In this case, unlike the conventional thermal vapor compression process (TVC-MED), the entrained vapor to be used in the ejector comes from the exhaust steam from the low pressure (LP) turbine instead of an effect of the MED unit. In order to optimize this latter concept (LT-MED-TVC), different configuration schemes have been studied. When thermodynamic efficiencies and costs are analyzed comparing the two more efficient configurations (PT-CSP/RO and PT-CSP/LT-MED), considering 58°C/0.18 bar of exhaust turbine steam conditions and 5.5 kWh/m3 of RO power requirements, initial results are very similar.