A comprehensive economic evaluation of integrated desalination systems, using fossil fuelled and nuclear energies, and including their environmental costs

Seawater desalination is now widely accepted as an attractive alternative source of freshwater for domestic and industrial uses. Despite the considerable progress made in the relevant technologies desalination, however, remains an energy intensive process in which the energy cost is the paramount factor. This study is a first of a kind in that we have integrated the environmental costs into the power and desalination costs. The study has focused on the seawater desalination cost evaluation of the following systems. It is supposed that they will be operating in the co-generation mode (simultaneous production of electrical power and desalted water) in 2015: - Fossil fuelled based systems such as the coal and oil fired plants and the gas turbine combined cycle plant, coupled to MED, and RO; - Pressurized water reactors such as the PWR-900 and the AP-600, coupled to MED, and RO; - High temperature reactors such as the GT-MHR, the PBMR, coupled to MED, with the utilization of virtually free waste-heat provided by these reactors. The study is made in real site-specific conditions of a site in Southern Europe. Sensitivity studies for different parameters such as the fossil fuel prices, interest and discount rates, power costs etc., have also been undertaken. The results obtained are then used to evaluate the financial interest of selected integrated desalination systems in terms of a detailed cash flow analysis, providing the Net Present Values, Pay Back Periods and the Internal Rate of Returns. Analysis of the results shows that among the fossil fuelled systems the power and desalination costs by circulating fluidized bed coal fired plant would be the lowest with current coal prices. Those by oil fired plants would be highest. In all cases, integrated nuclear energy systems would lead to considerably lower power and water costs than the corresponding coal based systems. When external costs for different energies are internalised in power and water costs, the relative cost differences are considerably increased in favour of the nuclear systems. Financial analysis further confirms these conclusions. (author)