The viability of renewable energy and energy storage as the power source for municipal- scale reverse osmosis desalination

Abstract

This research investigates the viability of renewable energy and energy storage to meet a significant and fundamental human need (in this case, large-scale drinking water supplies) unassisted by conventional power. The use of renewable energy to power reverse osmosis (RO) desalination plants to provide potable water for around 50,000 people in Newhaven, in South East England, and in Massawa in Eritrea, was investigated. The following energy sources, in a variety of combinations were specifically assessed: (i) wind power, (ii) wave power, (iii) solar power, (iv) tidal current power, (v) hydrogen production, storage and use in Fuel Cells. The following types of RO plants were studied: (i) No Brine Stream Recovery (BSR) RO plant, (ii) Pelton Wheel BSR RO plant, (iii) Pressure Exchanger BSR RO plant. Modelling was conducted to derive the amount of water that each RO plant would deliver from various combinations and amounts of renewable power input, at varying feedwater temperatures. Scenarios that were not able to deliver enough water to meet the users’ needs were scaled-up so that they could. The cost of the scaled-up scenarios that were able to meet the users’ water demands was compared with the costs associated with the equivalent conventionallypowered scenario over a 25-year life. Specifically, the following were considered: (i) A coal-fired plant with carbon capture and storage (CCS) at Newhaven and (ii) A diesel generator at Massawa. This comparison was made with and without the external costs associated with conventional energy production and use.