Economic evaluation of nuclear desalination systems

Abstract

This paper describes the detailed analyses of power and water costs for several nuclear reactors operating in a cogeneration mode (e.g. the 900 MWe French PWR, the advanced PWR, AP-600, the gas cooled, high temperature reactors, such as the GT-MHR and the PBMR) and coupled to two main desalination processes, e.g. multiple effect distillation (MED) and reverse osmosis (RO). Results for a specific site in a south Mediterranean country, Tunisia, are presented. It is shown in particular how the desalination costs could be further reduced by utilising waste heat from the GT-MHR and the PBMR type of reactors. Comparisons are made with desalination costs from the cheapest of fossil energy based systems, namely the 600 MWe gas turbine, combined cycle plant (CC-600) in various cost scenarios and in conditions specific to the selected site. Calculations are performed using the DEEP-3 software, recently developed by the International Atomic Energy Agency (IAEA). In the light of the results obtained, it is concluded that: a) Compared to the CC-600 system, all nuclear desalination options lead to much lower power production costs, as long as gas prices are ≥150 $/toe, and for discount rates of 5, 8 and 10%. Thus for example, at 8% discount rate and a gas price of 40 $/bbl (291 $/toe) for the CC-600, the kWh cost of the PWR-900 is 56% lower. Under the same conditions, that of the AP-600 is 49% lower; b) If the economic performances of the GTMHR and the PBMR, as announced by their respective developers, are indeed true than the GT-MHR would lead to the lowest kWh costs of all options considered. The kWh cost of the PBMR would be comparable to the large sized PWR-900; c) At 8% discount rate, the MED desalination cost by the PWR-900 and the AP-600 are respectively 46 and 42% lower than the corresponding cost by the CC-600 plant; d) The lowest costs with the MED plants are obtained by the GT-MHR and PBMR, utilising virtually free waste heat. Compared to the cost by the CC-600 + MED system, these reactors give desalination costs which are respectively 62% and 44% lower; e) For all energy sources, the desalination cost with the RO process is lower than with the MED process.