An Assessment of Renewable Energies in a Seawater Desalination Plant with Reverse Osmosis Membranes.

Federico Leon,Alejandro Ramos

doi:10.3390/membranes11110883

Abstract

The purpose of our study was to reduce the carbon footprint of seawater desalination plants that use reverse osmosis membranes by introducing on-site renewable energy sources. By using new-generation membranes with a low energy consumption and considering wind and photovoltaic energy sources, it is possible to greatly reduce the carbon footprint of reverse osmosis plants. The objective of this study was to add a renewable energy supply to a desalination plant that uses reverse osmosis technology. During the development of this research study, photovoltaic energy was discarded as a possible source of renewable energy due to the wind conditions in the area in which the reverse osmosis plant was located; hence, the installation of a wind turbine was considered to be the best option. As it was a large-capacity reverse osmosis plant, we decided to divide the entire desalination process into several stages for explanation purposes. The desalination process of the facility consists of several phases: First, the seawater capture process was performed by the intake tower. This water was then transported and stored, before going through a physical and chemical pre-treatment process, whereby the highest possible percentage of impurities and organic material was eliminated in order to prevent the plugging of the reverse osmosis modules. After carrying out the appraisals and calculating the amount of energy that the plant consumed, we determined that 15% of the plant’s energy supply should be renewable, corresponding to 1194 MWh/year. As there was already a wind power installation in the area, we decided to use one of the wind turbines that had already been installed—specifically, an Ecotecnia turbine (20–150) that produced an energy of 1920 MWh /year. This meant that only a single wind turbine was required for this project.

Highlights

70% of the Earth’s surface is covered with water, only 2.5% of this is fresh water, of which 90% is inaccessible—it is found in the subsoil, in the atmosphere, and frozen in the polar caps or in glaciers
It was found that the feed water came from the sea with a high salinity and was filtered at a low pressure in the pre-treatment system through reverse osmosis membranes, which carried out the desalination process
We considered the introduction of wind turbines to provide the energy needed for the correct development of the installation

Summary

Introduction

70% of the Earth’s surface is covered with water, only 2.5% of this is fresh water, of which 90% is inaccessible—it is found in the subsoil, in the atmosphere, and frozen in the polar caps or in glaciers. Desalination and water treatment facilities are becoming essential assets for economic and cultural development [5,6,7,8] This resource has been brought to a crisis point by global warming; climate change; drought; increased birth rates (according to the latest United Nations report [3,4,9]); the advance of agricultural, livestock, and urban borders; deforestation; pollution; and mismanagement. To face this problem, engineers have designed technological alternatives that allow for the use of brackish waters as a water supply, in addition to equitable means of distributing water resources, on which we depend as a population [5,6]. By taking these technologies into account, the seas and oceans can become infinite sources of water that are suitable for consumption

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