Basic cost equations to estimate unit production costs for RO desalination and long-distance piping to supply water to tourism-dominated arid coastal regions of Egypt

An arid climate with limited water resources and a growing tourism industry lead to water shortages in many coastal zones. Due to increasing demand, alternatives have to be found, e.g. desalination and long-distance water piping (long-distance defined here as equal to or further than 30 km), ecological sanitation, wastewater reuse or water demand management. This paper presents a cost comparison for two options to supply water of drinking water quality: Option 1 (Desalination with the reverse osmosis technology), or Option 2 (Long-distance water piping from the Nile), for the case of the touristic city of Sharm El Sheikh (Sharm) at the Red Sea in South Sinai, Egypt. Available water resources and current as well as future water demand figures for Sharm are presented. 91% of the current water demand stems from tourism; water is supplied mainly by privately owned RO desalination plants (86%). To analyze costs for Option 1, we compiled RO desalination plants costs (capital and O&M) for 14 RO plants in Egypt and 7 elsewhere for comparison. Unit production cost (US$/m 3 ) of water from small RO desalination plants in Egypt is in most cases lower than international trends for similar small capacity plants (250 to 5,000 m 3 /d), but unit O&M costs are higher. For Option 2, we present cost data for four long-distance piping projects in Egypt which pump groundwater or treated Nile water to cities in South Sinai including Sharm. We found that unit capital costs for those pipelines which are longer than 140 km are in fact above the cost of a possible RO desalination plant at any flow capacity. For unit production cost, desalination costs are lower than long-distance piping starting from pipelines with 300 km length or more and capacity ≥ 2000 m 3 /d. Empirical basic cost equations are produced to calculate unit capital cost (US$/m 3 /d) and unit production cost (US$/m 3 ) for both options in dependence of capacity for Option 1, and capacity and pipe length for Option 2.