Comparative assessment of the annual electricity and water production by concentrating solar power and desalination plants: A case study

The dual production of power and freshwater by the combination of Concentrating Solar Power (CSP) plants and desalination units, technology known as CSP + D, may help to solve the energy and water scarcity problems in arid and semi-arid regions. The lack of accurate annual analyses, crucial for the proper selection of the best CSP + D configuration, hampers the investment in this technology that has not been implemented on an industrial scale so far. This paper presents a simulation tool able to perform an annual assessment of power and freshwater production of CSP + D plants, based on a very accurate solar field model that uses time steps of 10 s. Three CSP + D configurations have been analyzed in two different locations, Abu Dhabi (UAE) and Almeria (Spain). Two of the three CSP + D configurations consider the multi-effect distillation (MED) technology for freshwater production, in low-temperature and thermocompression modes. The latter also accounts for the water and electricity demands for the selection of the best coupling arrangement. The annual results of the CSP + MED systems have been finally compared with those obtained from the third configuration, a Reverse Osmosis (RO) unit connected to a CSP plant. Results obtained indicate that, in both locations, the configuration leading to maximum water and electricity productions is CSP + RO (26% more of freshwater in Almeria and 10% more in Abu Dhabi). Only if the specific energy consumption of the RO process is above 5.4-5.6 kWh/m(3), the most optimum configuration would be CSP + MED at low temperature.