This study proposes the integration of reverse osmosis desalination with renewable energy sources and battery storage using energy-efficient power pinch analysis methodology for three different scenarios under an energy management strategy considering power supply and demand and power losses of the components in the system. The power cascade table and storage cascade table are introduced as numerical tools of power pinch analysis to determine the minimum outsourced electricity supply and available excess electricity for the next day, as well as the waste electricity, needed electricity, and the battery capacity for the system during a normal operation day. An optimization algorithm was applied based on the storage cascade table for a normal operation year to determine the optimal battery capacity for a dynamic freshwater demand to minimize the outsourced freshwater. Based on the energy management strategy, a case study in London, UK, showed scenario one as the best scenario with an optimum battery capacity of 1170.36 kWh and freshwater production of 40,604.5 m(3), which can minimize 60,096.9 m(3) of outsourced freshwater with a reasonable total annual cost of 503,159$/year. (C) 2017 Institution of Chemical Engineers. Published by Elsevier B.V. All rights reserved.