Page - 5 - in Water, Energy, and Environment - A Primer

1.3 ENERGYREQUIREMENTSANDCOSTSOF DESALINATION How much does it cost to desalinate salty water? Figure 1.1 shows a typical breakdown of costs for seawater desalination showing that energy is oneof the largest cost factors: Energy requirements (electrical+ thermal) for a range of saline waters are shown in Table 1.2 for various desalination technologies (these figures do not include the energy required for pre-treatment, brine disposal andmovement ofwater). Figure1.1 Breakdownof costs for seawaterdesalination (3). Table1.2 Energyconsumptionfordesalination technologies (4). Technology TotalEquivalentElectrical Energy (kWh/m3) MSF 13.5–25.5 MED 6.5–11 VCD 7–12 RO 3–5.5 Waterand itsglobal context 5