S. Nisan , Linda Volpi
Int. Journal of Nuclear desalination N°3 (2003 )
ABSTRACT:
In the context of the EURODESAL project, we were recently led to perform economic evaluations of desalination with existing and innovative reactors and to effectuate comparisons of the desalination costs with fossil and renewable energy sources. [See for exemple, A comprehensive economic evaluation…..].
Since the power cost data regarding various nuclear and non nuclear systems, as built in DEEP, dates back from the early nineties (collected for a predecessor of DEEP, known as CDEE) and because of the importance of power costs in desalination cost estimations, it was decided in EURODSAL and future studies to use the well validated CEA code SEMER [2] for power costs calculations. This data was then input into DEEP.
Detailed analysis then showed several discrepancies and pitfalls of coupling an economic evaluation code, such as SEMER to DEEP. This paper resumes our findings, which may be of interest to other DEEP users. The paper in particular deals with the following issues:
- Why is it that power costs from nuclear systems are systematically higher in DEEP than those given by the economic evaluations made by individual organisations, (In in our case, the SEMER code for example), even when the calculated construction costs are input into DEEP? This is clearly shown in IAEA TECDOC 1186.
- Why corresponding power costs for fossil energy systems are lower?
- Why in particular desalination costs from Gas-Turbine Combined Cycle power system, which is now considered to be the cheapest fossil fuel option, are higher than desalination costs by Pulverised Coal system?
- Why DEEP calculation results with the backup heat source are 40 % higher than those without the backup heat source?
- In a classical distillation system coupling, the vapour is extracted from the turbine blades at a given temperature and a given mass flow rate to produce a given amount of water. Thermodynamic analysis shows that this should lead to a loss of electrical power, depending upon the vapour temperature and desired product water capacity. This “lost shaft power” is indeed taken into account in the water costs calculations in DEEP. However, it is calculated by an older correlation which may not be any longer valid for innovative reactors. How can this be modified to take into account the real thermodynamic situation?
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