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This study addresses the imperative transition towards renewable energy for the powering of desalination technologies, focusing particularly on island contexts. The Canary Archipelago serves as a unique wind energy-desalination laboratory, with numerous experimental projects conducted since the late 1980s. The lessons learnt that are identified in this paper highlight the critical factors influencing project success or failure, including the modernization of desalination plants, the optimal selection of wind farm sites and turbine technology, adequate resources for operating and maintenance tasks, and optimal battery sizing to minimize system shutdowns. In this context, reverse osmosis emerges as the most advantageous technology for variable operating conditions. System interfaces between wind turbines and desalination units are also discussed and it is identified that further research is needed for mechanical or hydrostatic interface systems, while electrical interface systems suit low-medium water demand areas. Recommendations are given for system design and maintenance with the aim of providing valuable information for other island communities grappling with the water-energy nexus and climate change mitigation. [ABSTRACT FROM AUTHOR]

Because of their geographical isolation, many areas depend mainly on imported fossil fuels for their water and energy production. In this context, the Canary Islands are one such remote area. Due to the topography of the islands, there are numerous isolated areas on each of the islands far from the major population centres. These are known as ‘islands within islands’. The main aim of this paper is to determine the feasibility or otherwise of supplying from renewable energy sources both the energy and water needs of the 219 inhabitants of El Risco located in the municipality of Agaete on the island of Gran Canaria (Spain). For this purpose, the potential use of existing renewable resources in this isolated area has been analysed, using hydrogen as energy vector. A reverse osmosis (RO) plant is integrated into the system to ensure water self-sufficiency and, in turn, constitutes a double storage system (hydrogen-water). Based on the results obtained from the study, the technical feasibility of the system is confirmed, with an annual energy production of 1,743,031 kWh/year compared to a consumption of 672,314.32 kWh/year, as well as a potable water production volume of 46,546.80 m 3 /year obtained from the RO plant. The reliability of the system is confirmed in the economic analysis, obtaining a renewable electricity cost of 0.107 €/kWh compared to 0.18 €/kWh when using conventional electricity. [ABSTRACT FROM AUTHOR]

Abstract: Seawater desalination has become an important and ever-increasing industry which faces up the environmental situation of water scarcity present in some Mediterranean countries and in the Canary Islands (Spain). This activity presents several environmental drawbacks and negative impacts on marine ecosystems, originated mainly by the discharge into the sea of the generated brine. This emphasizes the need of introducing, in the short-term, new management proposals for this particular case which should be both economically viable and effective, not only for new setting up plants, but also for those already installed. As an alternative to brine disposal, an adequate system has been proposed and developed for the reuse of this saline waste coming from reverse osmosis desalination plants in the chlor-alkali industry by NaCl electrolysis in membrane cells. In this paper, the various treatment phases, necessary for the adaptation of this residue as an alternative raw material resource in the chlor-alkali manufacturing industry, are described. This study has been adapted to Pozo Izquierdo Reverse Osmosis Desalination Plant, in Gran Canaria. This new and different residue reuse as raw material supposes the production and exploitation of new chemical resources, as for example: chlorine, hydrogen gas, and caustic soda. [Copyright &y& Elsevier]

Abstract: The Canary Islands represent an almost perfect model of reference in the field of the water desalination. Starting from the 1960s, many desalination plants have been built to provide fresh water from non-conventional sources; making it necessary to search from other sources of supply, like seawater or brackish groundwater. Desalination in the Canary Islands has contributed to the progress and development of the islands, considering that its main economic activity is the tourism. In addition, water desalination has improved the population life quality, allowing a safe and continuous supply of water for domestic and agricultural consumption. Nevertheless, the desalination systems show a high power demand with a strong dependency on the non-renewable energies, basically of oil products. The desalination technologies that require electricity have gradually reduced their energy consumption, lowering the water supply bill. The reduction has been made possible thanks to the development and consolidation of efficient methods or through improvements in the equipment of desalination itself. In the present paper, we analyse with a retrospective vision the evolution experienced by the consumption of energy in the existing desalination plants in the Canary Islands, as well as the outlook in the long term. We will try to answer questions that we are considering nowadays, as it is for example whether the industry has arrived at the bottom line in energy consumption, what is the optimal size of a plant and its energy consumption of energy, etc. In our discussion we will consider the conditions of design and operation, as well as the different technological changes that have occurred during the life time of the installations. This exposition will allow us to learn in depth the existing deviations in the energy consumption and therefore, to include or understand the solutions adopted. The final objective is to contribute by explaining the state-of-the-art on the existing relationship between the energy consumption and the water desalination, by means of the knowledge of the improvements and decisions taken at each moment in a part of the world, where the water desalination accumulates more than forty years of experience. [Copyright &y& Elsevier]

Abstract: The prospective success of sustainable development in the Canary Islands, an insular land, will be essentially determined by the interrelation between four basic fields: water, energy, economy and environment. Economical, conventional and renewable energy resources and the local situation of water demand establish that the Canary Islands constitute a significant meeting point for desalination and renewable energy technologies. This paper aims to quantify the unit cost of fresh water generated from a representative wind-powered seawater reverse osmosis system (WPRO) as well as the exergy efficiency of the process (second law of thermodynamics) by means of thermoeconomy. Backup from the grid to balance temporary wind fluctuations is assumed; however, the mean annual energy backup is nil. Therefore the calculated unit cost of fresh water is determined exclusively by considering a wind-powered desalination system. [Copyright &y& Elsevier]

For >50 years the Canary Islands have been using seawater desalinization facilities in order to satisfy the freshwater demand of their main economic activity –tourism, which continues to contribute to the economic and social progress of the archipelago. However, this desalinization process involves the production of a "waste" product known as rejected brine, which is discharged from coastal regions and islands, whether it originates from public or private facilities. Rejected brines are potentially a serious threat to marine ecosystems. However, here we demonstrate that this "waste" can be processed and reused as a nutrient mineral solution for a hydroponic production system and also a source of freshwater. The efficiency of this management process in terms of fresh-water production and water recycling economy is also discussed. The aim of this paper is to change the attitude towards rejected brines, which should be treated as potential raw material to permit high savings in the running costs of leisure and tourist facilities around the archipelago. In addition, this will also have a positive effect on the environment, making desalinization more sustainable and environmentally friendly, which is nowadays an added value in customer and user satisfaction. • Rejected brine from seawater desalination can be used as a mineral and water source for hydroponic culture. • Rejected brine can be at the centre of a circular economy to reduce water consumption in leisure facilities. • Tomatoes obtained with rejected brine culture are safe and have better organoleptic qualities. [ABSTRACT FROM AUTHOR]