Production of desalinated water and electricity in a dual-purpose plant operating in a dispatchable electricity system — techno-economical analysis Original Research Article

A scarcity of potable water in Israel is a major concern for the Israeli government. In the next 10 years, extensive planning will be done to add ∼400–600 million m3 of potable water annually, mainly by building large seawater desalination plants. Furthermore, Israelʹs demand for electricity has escalated during the last decade at an average annual rate of 7.2%. This extremely high growth rate represents adding 500 MWe of electrical capacity each year in the coming years. As a result, the Israeli market represents a unique situation where large electrical capacity and large water quantities should be added simultaneously. Most of the added electricity capacity will be accomplished through new modern gas turbine combined cycles (GTCC). These GTCC will be operated as intermediate load units. The present work analyzes the techno-economic characteristics of two types of dual-purpose plants that differ by seawater desalination technology: seawater reverse osmosis and low-temperature multi-effect distillation. The power generation in the assessed alternatives is modern GTCC. Two scenarios were studied: Scenario A, where the dual-purpose plant operates according to daily optimal dispatch policy from the electricity production point of view and the desalination plant operates at its nominal capacity for the period; and Scenario B, where the dual-purpose plant operates as a base-load unit (electricity and water). The water production cost was calculated for the two scenarios and for the two technological variants of the dual-purpose plant, while taking into account the economic influence of non-optimal power generation represented by Scenario “B”.