Abstract
This study introduces an innovative strategy to simultaneously address two pressing global challenges: renewable energy’s intermittency and freshwater scarcity in arid regions. By redirecting surplus energy from renewable sources such as solar and wind into water desalination processes, energy is effectively stored in the form of freshwater. This approach leverages the water-energy nexus to offer a low-cost, sustainable alternative to traditional energy storage methods like batteries or pumped hydro systems, which often involve high infrastructure and environmental costs. The proposed method is particularly relevant for regions with abundant but inconsistent renewable energy supplies. By converting excess electricity into desalinated water, the system enhances both energy efficiency and water security, especially in arid and semi-arid areas. The research demonstrates that reverse osmosis powered by surplus renewable energy can produce freshwater at a significantly lower cost ($1.27/m³ and 3.5 kWh/m³) compared to conventional methods ($3.00/m³ and 5 kWh/m³). The study reinforces the value of this dual-purpose strategy as a practical, environmentally beneficial solution that strengthens the resilience of energy and water systems within the broader food-energy-water nexus.
Keywords
Introduction
Climate change is a challenge facing all countries around the world that requires urgent solutions to prevent worsening impacts on societies, economies, and the environment. Severe weather is becoming more common due to rising global temperatures, resulting in an increased prevalence of natural disasters such as heatwaves, hurricanes, and droughts; this has socioeconomic impacts on countries and their populations (McMichael et al., 2006). A particularly notable outcome of this worsening problem is the limited availability of water. Increased temperatures cause evaporation rates to rise, thus reducing access to fresh water in regions in which water scarcity is already impacting societies like the Middle East and North Africa. IPCC predictions suggest that both renewable surface and groundwater will be significantly reduced by the changing climate in most dry sub-tropical locations (Pachauri et al., 2014).
A number of different sectors can be impacted by water scarcity, including agriculture; however, an area of particular concern is public health because water sources that are potentially questionable are being increasingly used to satisfy demand, with the consequence being that waterborne diseases such as cholera and dysentery can increase in prevalence (World Health Organization, 2019). Furthermore, the dwindling supplies of water are the subject of increased competition both in local communities and among nations on a broader scale, which can worsen relations and ultimately result in conflict (Peter, 1993). Energy is one of the sectors that is most impacted by water issues as it is a key resource in traditional electricity generation methods; therefore, the entire process can become less efficient and secure when the water supply is inconsistent (Sovacool & Sovacool, 2009). The outcome is a vicious cycle in that water scarcity has a detrimental impact on energy production, thus exacerbating the existing resource management issues. Therefore, due to the interconnected nature of the challenges, a coordinated approach must be adopted with a particular focus on reducing harmful emissions, water management sustainability, and the funding of new technologies aimed at enhancing the efficiency of water and energy systems.
Despite significant advancements in renewable energy and desalination technologies, a critical gap remains in integrating these systems to address both energy storage challenges and water scarcity, particularly in arid and semi-arid regions. Existing solutions often treat energy storage and water supply as separate issues, relying on costly and resource-intensive technologies like batteries or pumped hydro storage while overlooking opportunities for synergy. Our study introduces a novel dual-purpose framework that converts surplus renewable electricity into desalinated water, effectively storing energy in the form of freshwater. This approach mitigates renewables’ intermittency and enhances water security, offering a cost-effective and environmentally sustainable alternative to traditional energy storage methods.
Water Scarcity in the Middle East
Cultural variances across the Middle East, along with the socio-economic conditions and the overall climate, can cause significant differences in the amount of water consumed per person. For example, the United Arab Emirates (UAE) is a global leader in terms of water consumption, as various factors, including high temperatures and freshwater constraints, have resulted in 500 l being consumed per person on average (Ibrahim et al., 2022). The lack of available water is a problem common to all countries across the Middle East, as average precipitation does not go above 200 mm, and the rate of evapotranspiration is very high, exceeding 2,000 mm (Shaban, 2022).
Water consumption among Iranians is influenced by a number of factors, including their income, education level, and the extent to which they are impulsive, where the latter has a proportional relationship with increased consumption (Baban, 2022). Wealth is a determinant of a country’s ability to manage water issues, as richer countries like Qatar are capable of exploiting state-of-the-art technologies to overcome water constraints, whereas poorer countries, such as Yemen, do not have enough resources to implement effective solutions (De Waal et al., 2023). The primary driver of water consumption in Iraq is agriculture, with other sectors contributing, including residential and industry, with livestock being a minor contributor (Omran et al., 2014).
The lack of consistent water supply in nations such as Lebanon has resulted in poorer quality of water and increased risk to public health, further exacerbating the challenges involved in managing water (Hashwa & Tokajian, 2004). In countries such as Jordan, where water is only supplied one day per week for 24 hr as a result of limited availability, residents are more prudent in their water usage (De Châtel, 2007). It is anticipated that the rising population and diminishing household sizes will cause water usage to increase by as much as 75% by 2044 in nations such as Israel, Syria, Lebanon, and Jordan, putting increased pressure on governments to implement more effective methods of conserving water (Kalifa et al., 2021; Martin, 1999; Scheumann & Schiffler, 2013).
The need for clean water will continue to rise in the Middle East, which is in line with expanding populations and economies despite the fact that available resources are declining. Projections indicate that water usage within the Gulf Cooperation Council (GCC) will be as high as 33 million m3 by 2025, exceeding the existing storage capacity of 25 million m3. While member states already lead the world in terms of desalination, with a daily capacity of 97.2 million m3 in 2020, it is anticipated that this will rise to 300 million m3 by 2050 (Malit & Naufal, 2017; Moossa et al., 2022).
Nevertheless, problems remain in these countries, including contaminated water, intensive consumption in the agricultural industry, and a lack of modern infrastructure. Despite the critical nature of desalination, it uses a significant amount of energy and is a primary contributor to the country’s greenhouse gas emissions. Furthermore, one of the by-products of the desalination process is brine, which can be environmentally harmful to marine ecosystems, and Middle East countries, including Qatar, Kuwait, Saudi Arabia, and the UAE, account for 55% of all brine generated globally (GCC, 2024; Jones et al., 2019).
Desalination in Countries With Limited Water
One of the primary methods of solving the problem of extreme water shortage in the Middle East is now desalination, as the rising populations, increased urbanization, and economic growth are all contributing to the already existing problems of arid environmental conditions and limited freshwater availability in these areas. As conventional sources, such as aquifers and rivers, are increasingly exhausted, desalination, in which salt water is converted into drinking water, has emerged as a reliable option. Countries in the Middle East, such as Kuwait, Israel, the UAE, and Saudi Arabia, currently lead the world in the implementation of such technologies. Figure 1. highlights the MENA region’s high solar irradiance and wind energy potential, particularly across the Arabian Peninsula and North Africa. The solar map illustrates daily solar exposure exceeding 6 kWh/m² in most areas, while the wind map shows mean wind speeds above 6 m/s in coastal and desert regions. These abundant renewable resources underscore the region’s suitability for integrating solar and wind energy into water desalination systems, supporting both energy storage and water security objectives.
Renewable energy potential (solar and wind) in the MENA region.
Nevertheless, this process is linked with a number of challenges, including the amount of energy needed to power desalination, as the energy sourced from fossil fuels is one of the primary drivers of increasing carbon emissions. Moreover, one of the environmental consequences of desalination is brine production concentrated with salt and chemicals. The development of innovative desalination technologies is alleviating this problem, one of which is the integration of energy from renewable sources like solar, which can reduce both the level of energy consumed and associated costs, making the process more sustainable in general (Al-Addous et al., 2024; Maftouh et al., 2023).
For a region like the Middle East, in which water security is a persistent problem as a result of the changing climate, desalination represents a solution for ensuring that water demand is met in the immediate future while also providing long-term water security. By integrating desalination into general water management strategies focused on natural resource conservation, wastewater re-usage, and water preservation, the water supply system across the region will become more resilient and sustainable (Zaidi et al., 2023).
Gulf Cooperation Council (GCC) member states are exploiting their plentiful supply of solar energy to integrate renewable sources with conventional desalination approaches, causing a reduction in the amount of energy consumed and harm to the environment (Janowitz et al., 2022). While the initial costs of offshore facilities may be high, their environmental benefits are favorable, and they can potentially reduce long-term water production costs (Piuri et al., 2022).
Although it can be advantageous, desalination remains nascent, as it only provides potable water for approximately 1% of the world’s population. On the other hand, more than 45% of desalination facilities globally are located in the Middle East and North Africa (MENA) region, emphasizing how critical it is for water security (Esmaeilion et al., 2021; Salman & Aswad, 2022). One industry in which solar-powered desalination systems have demonstrated potential is agriculture, as they can facilitate the cultivation of crops while ensuring that environmental concerns are managed (Awaad et al., 2020). The problem of limited water supplies in the region can be sustainably resolved by integrating renewable energy with desalination, which will allow both economic and environmental aspects to be addressed (Assad et al., 2022).
Desalination consumes large amounts of energy to power technologies such as multi-stage flash distillation and reverse osmosis. Consequently, electricity supplies are placed under considerable strain, particularly in areas that are highly dependent on desalination to supply water. Climate change is worsened by the use of fossil fuels to generate energy, which also results in increased water consumption, generating a vicious cycle that must be broken with innovative solutions (Esmaeilion et al., 2021). Integrating renewable energies such as wind, solar, and geothermal energy offers potential as it significantly reduces the carbon footprint of desalination. For example, as the Middle East has a plentiful supply of sunlight, solar systems are particularly suitable, which will enhance the long-term sustainability of desalination. This strategy conforms with worldwide goals of reducing greenhouse gas emissions while also enhancing water security for future generations (Awaad et al., 2020; Assad et al., 2022).
Renewable Energy Potential
Economic and environmental problems in the Middle East arising from climate change can be addressed by adopting renewable energies. Studies indicate that the use of such sources can lead to a significant reduction in greenhouse gas emissions, which is beneficial for the environment. Literature pertaining to the MENA region indicates that renewable energy adoption has the potential to be beneficial for efforts to reach emission reduction targets, providing support for calls for sources that are more favorable for the environment to be incorporated into the energy mix (Maalel, 2024; Yahyaoui & Ghandri, 2024).
Studies have revealed the environmentally harmful effects of economic growth and urbanization, reinforcing the need for renewable energy adoption as a solution to mitigate these problems (Abdulraqeb et al., 2024). However, the reality is that efforts to adopt renewable energies are impacted by a number of factors, including development, financial growth, and governance, but they play an important role in strategies aimed at reducing harmful emissions (B. Li, Amin, et al. 2024). A reduction in greenhouse gas emissions is an important factor in diminishing carbon emissions, and it can be facilitated by both green finance and technology (Alariqi et al., 2023; Al-Kasasbeh et al., 2024). It is critical that the effects of greenhouse gases are reduced by shifting to clean energy, given the severity of the problem (Saleh et al., 2023).
The abundance of solar, wind, and geothermal energy sources in the Middle East makes it particularly well-positioned to exploit these beneficial resources, which can potentially reduce the region’s emissions (Myradowich, 2023). The increasing emissions in the area are both environmentally harmful and detrimental to public health, but econometric analyses have shown that potential solutions to these problems include green technologies and renewable energy (Albaker et al., 2023). Substituting renewable energy for fossil fuels is a critical factor in efforts to counterbalance the detrimental impacts of climate change in the Middle East, which will also facilitate sustainable economic growth through enhanced energy efficiency (Satari Yuzbashkandi et al., 2024).
One of the major problems preventing the adoption of renewable energies is that sources like wind and solar are relatively inconsistent. To resolve the issue of interrupted supply, it is possible to store energy using approaches like thermal storage, pumped hydro, and batteries, as this allows surplus energy to be stored during periods of intermittency. By effectively storing energy in this manner, the stability of the energy is ensured, thus allowing renewable technologies to be deployed more widely and the dependence on fossil fuels to be reduced (Senarathna et al., 2023). For instance, dips in solar energy production can be mitigated by integrating storage systems into solar plants, making the power supply more reliable (Zhu et al., 2023). Likewise, hybrid systems become more flexible through the introduction of energy storage, enhancing transmission and dispatch efficiency (Ponce et al., 2023).
Despite the existence of large-scale alternatives such as compressed energy storage and pumped-storage hydropower, there is a general preference for batteries as they are more adaptable and not geographically limited, and they are especially used together with wind turbines and photovoltaic arrays (Thakoordeen, 2019). However, it has not yet been possible for the costs of renewables with battery storage to match those of fossil fuels, and it is estimated that cost parity will not be achieved until 2050 if positive conditions prevail (Chowdhury & Willis, 2023). Nevertheless, pumped-storage hydropower has shown potential as a result of its extended lifecycle and expandability (Cosgrove et al., 2023, Desai, 2022). Technologies such as modular multi-level converter (MMC)-based HVDC networks, in conjunction with flywheel energy storage, can also increase the stability of power grids when supply fluctuates (Hossain et al., 2023).
State-of-the-art techniques such as stochastic dual dynamic programming (SDDP) offer adaptive, cost-effective methods of integrating renewable energies into power grids, whereas long-duration energy storage (LDES) systems offer specific benefits in terms of lowering electricity costs and displacing low-carbon generation, given that economic goals are achieved (Cordera et al., 2023; Sepulveda et al., 2021). In general, the ability to store energy is a critical solution for resolving the problem of intermittent renewable energy supply, which can increase the sustainability and reliability of the power grid.
Energy Storage
As summarized in Table 1, there are different energy storage technologies.
Overview of Energy Storage Technologies: Advantages, Disadvantages, Technical Specifications, Environmental Impact, and Economic Factors.
Explores the integration of energy storage systems with water desalination, focusing on renewable energy-based technologies to improve the sustainability and efficiency of desalination processes. The study highlights that renewable-powered desalination systems, such as those relying on solar or wind energy, offer an effective solution for energy storage challenges, particularly in areas with abundant renewable resources but limited water access. Additionally, examines the role of pre-combustion carbon capture in advancing sustainable development goals (SDGs), emphasizing the environmental benefits of integrating clean technologies into existing energy frameworks. Further, various renewable energy systems are assessed, identifying key challenges, sustainability indicators, and their contributions to the SDGs. These studies underscore the importance of renewable energy in achieving sustainable water and energy solutions, presenting both desalination and carbon capture as critical to reducing environmental impact and supporting global sustainability efforts (Maghrabie et al., 2023; Olabi et al., 2022, 2023).
Energy storage technologies each have unique strengths and weaknesses, making them suitable for different applications depending on specific needs and constraints.
Pumped hydro storage (PHS) is a mature and highly efficient technology ideal for large-scale energy storage. It offers long-duration storage with round-trip efficiencies of 70% to 80%. However, its implementation is site-specific, requiring significant land use and having a notable impact on aquatic ecosystems. The high capital costs are offset by low operating expenses, making it a viable option for large, long-term projects.
Lithium-ion batteries are favored for their high power density, long cycle life, and versatility in various applications. They provide energy densities between 150 and 250 Wh/kg and power densities of 1,000 to 3,000 W/kg. Despite their decreasing costs, they pose environmental challenges related to mining and recycling, as well as safety concerns due to the risk of thermal runaway.
Compressed air energy storage (CAES) is another large-scale option with flexible dispatch capabilities. Although it is less efficient, with round-trip efficiencies of 40% to 55%, and shares the site-specific limitations of PHS, it has a relatively low environmental impact and offers long-duration storage at a high initial investment but with low operating costs.
Flow batteries stand out for their long cycle life and deep discharge capabilities, making them environmentally friendly with a cycle life exceeding 20,000 cycles. However, their lower energy density (20–40 Wh/L) and high capital costs, coupled with ongoing research and development, make them less competitive than lithium-ion batteries for some applications.
Thermal energy storage (TES) offers high energy density and the potential for long-duration storage, making it suitable for waste heat recovery. However, it suffers from low power density and heat losses, which can complicate its use. The environmental impact varies with the technology employed, and there is potential for cost reduction as the technology matures.
Flywheel energy storage provides fast response times and high power density, with long cycle lives, making it useful for applications requiring quick energy dispatch. However, its lower energy density and the risks associated with high rotational speeds limit its broader use. The high capital cost remains a barrier despite its minimal environmental impact.
Supercapacitors excel in applications requiring high power density and fast charging/discharging, with an impressive cycle life exceeding one million cycles. However, their low energy density and high self-discharge rate limit their energy storage capabilities, making them more expensive on a per-kWh basis and better suited for short-term storage.
Hydrogen storage offers high energy density and the potential for carbon-free energy, positioning it as a key player in future energy systems. However, challenges related to infrastructure, energy losses, and safety concerns, along with high capital and operating costs, indicate that significant development is still needed for widespread adoption.
Gravity-based storage is a low-environmental-impact option with the potential for long-duration storage and grid stabilization. However, its low power density, site-specific nature, and lower efficiency make it less flexible compared to other technologies. The high initial costs are balanced by low operating expenses, making it suitable for specific, large-scale applications.
Methodology
The methodology of this research involves a multi-step analytical approach to evaluate the concept of using surplus renewable energy for seawater desalination as an alternative energy storage method in water-scarce regions. The study begins with an extensive literature review on water scarcity, desalination technologies, and conventional energy storage systems. It then builds a theoretical framework that positions desalinated water as a viable energy storage medium, aligning this concept with the broader water-energy nexus. Next, the research conducts a comparative analysis between traditional energy storage methods—such as lithium-ion batteries and pumped hydro—and desalination, particularly reverse osmosis (RO). The comparison focuses on technical specifications, energy consumption, environmental impact, scalability, and costs. The RO process was chosen due to its relatively low energy demand and compatibility with intermittent renewable sources like solar and wind. Using data from real-world case studies, the study models different scenarios where excess renewable energy is directed to desalination plants to produce freshwater, which is then stored for future use. The environmental and economic implications of this approach are assessed, highlighting its potential to reduce carbon emissions, minimize storage infrastructure costs, and enhance long-term water and energy security in arid regions.
The scalability of using desalination as an energy storage medium depends on the compatibility between intermittent renewable energy sources and the operational demands of reverse osmosis (RO) systems. RO desalination requires steady energy input, yet solar and wind supply are variable. To address this mismatch, systems can be designed with smart controllers to ensure stable plant operation. Additionally, modular RO units allow for decentralized deployment, enabling scalable solutions that match local freshwater demand and available renewable energy. Grid-connected configurations offer further flexibility, allowing energy surplus to be dynamically allocated between desalination, battery storage, or direct consumption. These scalable, hybridized models enhance the technical feasibility of water-as-storage systems across diverse geographic and economic contexts. A suggested system is proposed in Figure 2 of the energy-to-water storage system. Surplus renewable energy (solar/wind) is converted via an inverter/controller to power a reverse osmosis (RO) desalination unit. The produced freshwater is stored in a reservoir for later use, serving as an energy storage medium. Additional system outputs include brine disposal and emergency water supply, with optional grid feedback for surplus energy not used in desalination.
Conceptual diagram of surplus renewable energy converted to freshwater via RO desalination for storage and emergency use.
Desalination Energy Requirements and Cost
This section provides an overview of the cost and energy requirements associated with desalination processes, examining key technologies that influence operational expenses and energy consumption in various desalination technologies.
Desalination Energy Requirements
Table 2 summarizes the energy requirements (both thermal and electrical) for different desalination technologies. Electricity consumption (kWh/m³), which is required across all desalination methods, and thermal energy consumption (kWh/m³), which is primarily associated with thermal desalination techniques like multi-stage flash (MSF) and multi-effect distillation (MED). For these thermal processes, energy requirements vary significantly based on the gain output ratio (GOR), an efficiency measure related to steam usage.
Energy Requirements (Both Thermal and Electrical) for Different Desalination Technologies (DESWARE, 2021).
Our study primarily focuses on electrical energy consumption in desalination processes, particularly in reverse osmosis (RO), due to its widespread use and efficiency advantages. Electrical desalination processes like RO are more energy-efficient than thermal methods and align well with renewable energy integration, making them a sustainable choice for many regions.
Reverse osmosis (RO) was selected as the primary desalination method in this study due to its high energy efficiency, scalability, and widespread adoption in water-scarce regions, particularly in the MENA region. Compared to thermal desalination methods like multi-stage flash (MSF) or multi-effect distillation (MED), RO systems operate at significantly lower energy consumption levels (3.5 kWh/m³ on average) and offer lower production costs (as low as $1.27/m³ when powered by surplus renewable energy). These figures were chosen based on well-documented performance metrics from existing renewable-powered RO installations, such as those in Saudi Arabia and Israel, and reflect realistic and regionally applicable benchmarks. Combining operational efficiency and economic viability makes RO the most suitable and practical technology for integrating energy storage and water production in renewable-based systems.
Desalination Cost
A number of different factors impact desalinated water production costs, such as the cost of water, water quality criteria, as well as the composition of feed water, and such costs have been effectively reduced as a result of new reverse osmosis (RO) technologies (Rosen & Farsi, 2022; Shokri & Fard, 2023). Nevertheless, costs, in general, can be significantly affected by specific characteristics of the region, like social and environmental factors, as well as externalities and subsidies, which can often result in costs being doubled when factored into the overall costs (Saleh & Mezher, 2021). The International Atomic Energy Agency has developed the Desalination Economic Evaluation Program, which offers a platform by which such costs can be evaluated, particularly in situations where various desalination techniques are used in conjunction with different power sources (Ismail & Matsuura, 2022). Conventional water sources remain the more inexpensive option, as energy consumption is a key factor driving costs, specifically in methods that consume considerable amounts of energy, such as multi-effect distillation (MED) and multi-stage flash (MSF). Both costs and environmental damage can potentially be reduced by integrating renewable energies like wind or solar into the process of desalination. New technologies are being developed that can provide both efficient and sustainable desalination, including solar steam generation (SSG) and solar-driven interfacial water evaporation (SIWE), reinforced by optimization methods such as Niching Chimp Optimization Algorithms (HGS-NChOA) and Hunger Game Search, which can potentially generate significant cost reductions. Furthermore, desalination processes powered by renewable energies can become more environmentally and economically viable through the implementation of hybrid energy systems and demand-side water management strategies, increasing their importance as a solution for the problem of water scarcity, particularly in severely impacted areas such as the Middle East.
Although desalination is both reliable and efficient, it can be a very expensive process, with costs often double or triple those of conventional water sources, and this remains a problem that needs addressing (Ziolkowska, 2015). Operational costs and energy consumption can be increased by problems like membrane fouling, although technological developments in this area have produced improved anti-fouling membrane materials that can mitigate such costs (Das et al., 2022). Furthermore, there is now a greater demand for irrigation around the world, and the demand for desalinated water is impacted by the extent to which such irrigation systems are efficient, subsequently influencing the allocation of financial resources into energy for such processes (Caldera & Breyer, 2023; Ghaffour et al., 2013). Desalination costs vary significantly depending on the chosen technology, such as membrane methods like reverse osmosis (RO) and electrodialysis (ED), or thermal techniques like multi-effect distillation (MED) and multi-stage flash (MSF), with energy expenses accounting for around 50% of production costs (Al-Karaghouli & Kazmerski, 2013). Integrating renewable energy sources has reduced energy costs, enhancing desalination’s economic and environmental viability, especially in remote locations (Kabeel et al., 2013). Factors influencing desalination costs include economic conditions, local environmental characteristics, and technology, leading to regional variations. For instance, seawater reverse osmosis (SWRO) costs range from $0.5 to $0.6/m3 in Israel but reach $5.2/m3 in Australia, highlighting the impact of location-specific factors (Glueckstern & Anahory, 2023). The true cost of desalinated water in the UAE is significantly increased by externality costs associated with multi-stage flash (MSF) and multi-effect distillation (MED) technologies, where the costs of the former vary from $0.548 to $1.174/m3 and $0.297 and $0.702/m3 for the latter, resulting in average increases of 81.9% and 65.8%, respectively, if externalities are taken into consideration (Saleh & Mezher, 2021).
Reverse osmosis systems powered by renewable energies in Saudi Arabia incur different costs in the production of water, where costs for RO-Wind systems vary from $1.273 to $1.366 and costs for RO-PV systems from $2.048 to $2.119/m3 according to the capacity of the system. Costs have been significantly decreased as a result of technological developments and increased efficiency, allowing desalination systems to become more competitive. Renewable-energy-driven desalination systems have become increasingly cost-effective and environmentally friendly, with costs for desalinated water ranging globally from $0.45 to $2.51/m3, depending on factors like water salinity, production capacity, and technology used (Ben-Mansour, Al-Jabr & Saidur, 2019; Ziolkowska, 2015). Reverse-osmosis (RO) systems typically cost around $0.5/m3. At the same time, thermal processes are estimated at $1.0/m3, with brackish and seawater processing costs at $0.6 and $1.0, respectively, anticipated to decrease further with technological advancements (Reddy, 2008; Zhou & Tol, 2005). Solar energy has emerged as a promising renewable source for desalination, with innovative technologies like solar-driven interfacial water evaporation (SIWE) and self-sustaining hybrid HIWE systems achieving efficiencies of 90.8% and steam generation rates of 2.01 kg m−2 hr−1 by utilizing temperature-salinity gradients to sustain continuous steam production (Li He, et al., 2024). These advancements underscore the potential of renewable-driven desalination as a sustainable and cost-efficient solution for water scarcity. In a different method, materials sourced from waste are used to produce solar evaporators, with one example being photothermal membranes produced using fibers derived from cattail leaf and carbon. The resultant rate of evaporation achieved was recorded as 1.22 kg m−2 hr−1, and it can produce around 5.3 kg of water daily per square meter, meeting the daily water needs of two adults (Wu et al., 2023). Moreover, salt accumulation is a common problem, and decorating a solar steam evaporator with Holo-Cellulose (HC) and Polypyrrole (PPy) is capable of resolving this issue, generating efficiency and evaporation rates of 93.4% 1.45 kg m−2 hr−1, respectively (Xu et al., 2023).
As technologies continue to develop, new approaches are emerging, such as the Hierarchical Salt-Rejection (HSR) approach, which has the ability to enhance salt resistance and the evaporation rate; it has achieved an evaporation rate of 2.84 kg m−2 hr−1 under steady operation in brine with high levels of salt content for extended periods (Mao et al., 2024). New biometric designs have also shown promise, including a corrugated evaporator in which Fe nanoclusters enveloped by carbon nanotubes are used to maximize the evaporation at 4.2 kg m−2 hr−1, achieving a steam water evaporation rate of up to 91% under ideal conditions (Wang, Shang, et al., 2023). There are environmental concerns associated with brine discharge from desalination processes. One promising approach is brine mining, which involves extracting valuable minerals and metals (e.g. magnesium, lithium, and potassium) from the concentrated waste stream, turning a waste product into a commercial resource. This process not only minimizes the volume of harmful discharge but also creates an economic incentive for desalination expansion. Additionally, beneficial reuse of brine in applications such as aquaculture, salt production, or industrial processes (e.g. cooling water or chemical feedstock) is gaining traction in regions with limited freshwater but ample saline resources. These integrated strategies, when combined with renewable-energy-powered desalination, can significantly reduce the overall environmental footprint and support more sustainable water management practices in arid regions.
Additionally, state-of-the-art materials such as hierarchical FeS2/TiO2 nanotube arrays on a Ti mesh provide an evaporator that is both self-resistant and self-floating, with the capacity to remove organic pollutants and pathogens. The evaporation rate achieved by this system reached 1.05 kg m−2 hr−1 in a 20 wt% NaCl solution, with this high level of performance being sustained in excess of 20 days (Wang, Zhao, et al., 2023). Lastly, hydrogen is capable of acting as a carrier of energy when solar desalination is integrated with hydrogen production, enabling the supply and demand of electricity to be balanced and producing a system that offers both sustainability and efficiency in producing drinkable water and green hydrogen, with an efficiency of approximately 38.9% on average (Wen et al., 2024). The aforementioned approaches demonstrate how solar energy can potentially be a highly beneficial solution to the problem of water scarcity, with the distinct technologies providing different benefits in terms of scalability, sustainability, and efficiency.
The various desalination technologies available consume varying amounts of energy. Approaches based on membrane technologies such as reverse osmosis (RO) provide the optimal energy efficiency, with a requirement of approximately 1.9 to 11.9 kWh/m³ for medium to large-scale brackish water desalination. Conversely, thermal techniques consume more energy, with rates of 17.1 kWh/m³ for multi-stage flash (MSF) and 11.9 kWh/m³ for multi-effect distillation (MED). Further reductions in consumption rates, ranging from 1.5 to 21.1 kWh/m³, can be achieved through the integration of renewable energies like wind and solar. Desalination costs, in general, are highly influenced by such energy demand, where such costs increase as the energy required to power such processes rises (Antonyan, 2019).
A study conducted in the city of Zakho in the Kurdistan Region of Iraq investigated the cost of generating electricity from photovoltaic (PV) systems. Analysis was conducted on three different PV systems, namely a fixed system, a single-axis tracking system, and a dual-axis tracking system, with the cost of electricity reported to be 0.0826, 0.0489, and 0.0441 USD/kWh for each system, respectively. The results of this study indicate the economic viability of using PV systems in this region, specifically those with tracking technology installed. Moreover, the results suggest that PV systems can now rival traditional electricity production methods in which fossil fuels are used (Qader et al., 2022).
Desalination processes can become more cost-effective and sustainable through the integration of renewable energies such as wind, solar, and geothermal energy, which can replace fossil fuels that are subject to varying prices and environmental regulations (Al-Obaidi et al., 2024). For example, innovative techniques like membrane distillation and reverse osmosis (RO) can be powered effectively by solar energy, reducing both the amount of energy consumed and overall costs (Tashtoush et al., 2023). Additionally, the utilization of the latest optimization techniques like Hunger Game Search and Niching Chimp Optimization Algorithms (HGS-NChOA) can enhance the economic feasibility of these types of systems, while integrating photovoltaic panels (PV) and wind turbines can generate cost reductions of $0.233/m3 (Guo et al., 2024).
As potable water becomes more costly and scarce, integrating renewable energy sources into distributed systems is a potential solution to this problem, particularly as the situation continues to worsen as a result of the problems caused by climate change (Menon, 2024). The optimization of the sizing of renewable energy-powered RO systems can be achieved through a coordinated approach in which demand-side water management (DSWM) is integrated; this can reduce costs and make the system more sustainable, with reductions in total annual costs (TAC) and total environment costs (TEC) of 5.7% and 32.44%, respectively. In more isolated regions, hybrid energy systems (HES) in which conventional energy sources such as diesel generators are combined with renewable sources can offer superior cost-effectiveness, optimizing both the cost of energy (COE) and net present cost (NPC) while simultaneously lowering the carbon footprint (Ba-Alawi et al., 2023; Babaei et al., 2024; Pietrasanta et al., 2023; Table 3).
Provides an Overview of Desalination’s Cost and Energy Requirements Across Various Regions and Technologies.
Renewable energy systems for desalination facilities can now be modeled and optimized using software such as HOMER, which is particularly beneficial for locations with abundant renewable resources, like the Canary Islands, where optimal approaches can be devised to satisfy energy consumption efficiency needs (Avila Prats et al., 2024). Smart management practices, such as the intermittent operation of oversized RO membranes, can significantly reduce costs and carbon emissions, enhancing the economic viability of integrating renewable energy into large-scale desalination operations (Schär et al., 2023). Renewable energy integration reduces operational expenses and provides environmental benefits, making it a sustainable method to address global water scarcity challenges. Advancements in solar desalination systems highlight their energy efficiency and environmental advantages, with thermodynamic optimizations and heat transfer enhancements improving performance and sustainability (Dhivagar et al., 2023). Life cycle assessments demonstrate their ability to minimize resource consumption and emissions, positioning solar desalination as a more sustainable alternative to traditional technologies (Dhivagar et al., 2021). Emerging solar technologies have further enhanced system designs, increasing their feasibility for large-scale implementation (Rahul et al., 2023). Economic and environmental analyses underline the cost-effectiveness of solar-driven desalination, significantly reducing energy consumption and greenhouse gas emissions while adapting to diverse geographical and climatic conditions (Dhivagar, Deepanraj, et al., 2022). These technologies offer a robust and scalable solution to global water and energy challenges, particularly in regions with abundant solar resources (Dhivagar, Shoeibi, et al., 2022).
Results and Discussion
This study proposes a novel solution to utilize surplus renewable energy by converting it into desalinated water, effectively storing energy in a usable form. This approach addresses the inconsistency and unpredictability of renewable sources like wind and solar, which often produce excess energy that, without proper storage, would otherwise go to waste. Historically, this issue has been addressed by investing in expensive systems of storing energy like pumped hydro storage, batteries, and different types of large-scale energy storage facilities. Despite the effectiveness of such systems, they can be very costly in both economic and environmental terms. For instance, the raw materials involved in the production of batteries can be expensive, and this process can be very involved; additionally, their lifecycle can be short, which adds further costs and problems in terms of disposal. On the other hand, the land requirements for pumped hydro storage can be excessive and environmentally harmful, meaning geographic limitations restrict its viability.
To quantify the feasibility of water-as-energy storage, we conducted a comparative cost analysis of storage systems. Lithium-ion batteries typically cost between $250 and $500/kWh with an average lifespan of 10 to 15 years, while pumped hydro storage (PHS) ranges from $100 to $200/kWh but requires specific topographical conditions and large capital investments. In contrast, the energy equivalent cost of storing energy via renewable-powered reverse osmosis (RO) desalination ranges between $50 and $80/kWh, depending on location. This is based on a conversion of 3.5 to 4.5 kWh of energy per m³ of water, and production costs varying regionally—from as low as $1.27/m³ in Saudi Arabia (due to subsidies and scale) to $5.20/m³ in Australia (due to higher electricity tariffs and O&M costs). The return on investment (ROI) for renewable-powered RO systems typically ranges from 4 to 7 years, depending on local energy prices, grid parity, and water demand. Subsidy structures, energy market volatility, and water scarcity severity play a critical role in determining the economic viability of this solution, making it particularly attractive for arid and energy-rich regions where conventional storage methods are less practical or more expensive.
The proposed solution works by channeling surplus electricity from intermittent renewable sources—such as solar and wind—into reverse osmosis (RO) desalination systems to produce freshwater, effectively storing energy in the form of a vital resource. This practical implementation can be integrated into existing water infrastructure in arid regions like the GCC, where solar irradiation is abundant but water scarcity is severe. For instance, rather than curtailing excess solar power during peak production, this energy can drive RO desalination units to fill local reservoirs. Compared to traditional energy storage solutions like lithium-ion batteries, which cost over $300/kWh and have limited lifespan and environmental concerns, desalination-powered storage achieves dual benefits: water provision and energy utilization, at a cost as low as $1.27/m³. However, practical challenges include matching energy surpluses to desalination plant operation, ensuring grid compatibility, and addressing brine management. Nonetheless, with proper smart controls and hybrid system design, this approach not only offsets water shortages but also provides a sustainable, cost-effective alternative to conventional energy storage systems.
In the current study, an innovative method is presented, one in which surplus renewable energy can be repurposed for powering desalination plants, thus allowing energy to be stored in the form of water. Despite the abundance of renewable energy options in certain regions from sources such as wind and solar, the supply can be inconsistent, and new thinking is required to resolve this problem. This study addresses the challenge of fluctuating renewable energy supply by proposing an innovative solution: using surplus energy for water desalination. Unlike traditional storage methods, such as batteries and pumped hydro, which are costly and environmentally harmful, this approach converts excess electricity into freshwater, stored in reservoirs for later use during low-energy production or high-demand periods. This dual-purpose strategy enhances both energy storage and water security, particularly in arid regions with abundant renewable resources. The integration of solar and wind energy into desalination processes lowers energy consumption and production costs, reducing desalination costs by up to $0.223/m3 in hybrid systems. By utilizing surplus energy directly, this approach eliminates the need for expensive infrastructure, providing a sustainable, cost-effective alternative to traditional energy storage while supporting water and energy resilience. From an economic perspective, this technique is superior to conventional energy storage systems. The study determined that the cost-effectiveness of photovoltaic systems, specifically those with tracking technology installed, is good. Suppose desalination is powered by such surplus renewable energy. In that case, energy can be stored practically as part of the process by converting it into desalinated water, a valuable commodity in regions with limited resources.
On the environmental side, producing water and storing energy are traditional processes with a significant carbon footprint, which can be significantly reduced by adopting such an approach. The conversion of surplus renewable water to desalinated water eliminates the necessity for storage systems reliant on fossil fuels, thus diminishing carbon emissions. As a result, the urgent demand for potable water can be met through this strategy, which is also more environmentally friendly than energy storage and offers a favorable solution for managing both energy and water. Additionally, the study demonstrates that hybrid energy systems (HES) are promising, as they can combine renewable energies with traditional sources for more isolated regions, optimizing costs and reducing emissions while simultaneously storing energy in the form of desalinated water.
Environmental sustainability is a critical component of evaluating energy-water systems. One concern in desalination is brine discharge, which can impact marine ecosystems if not properly managed. Emerging solutions such as brine mining offer a dual benefit: mitigating environmental harm while recovering commercially valuable minerals like lithium, magnesium, and rare earth elements. Recent pilot projects in Saudi Arabia and the UAE demonstrate technical feasibility, particularly when co-located with large-scale solar RO plants. Additionally, zero-liquid discharge (ZLD) systems—which recover nearly all water and leave a solid waste stream—are increasingly viable in high-regulation contexts, although they currently involve higher energy inputs.
The research identifies important strategic and technological developments that make storing surplus energy as desalinated water more efficient. Implementing methods such as demand-side water management (DSWM) and optimized operation, such as the sporadic usage of oversized RO membranes, can significantly reduce carbon emissions and energy costs. This strategy provides a practical alternative involving the use of surplus renewable energy to desalinate water as a substitute for more expensive and complicated storage systems that incorporate renewable energy. Consequently, challenges become opportunities, whereby excess energy can be exploited by using it to store energy that can be kept in reserve for future periods of demand. Hence, the reliability of the water supply will be enhanced, making it more cost-effective and sustainable, which is in line with worldwide sustainability goals and supports the efforts of countries with limited water in confronting this worsening issue (Ba-Alawi et al., 2023; Babaei et al., 2024; Pietrasanta et al., 2023).
Table 4 provides an overview of the proposed solution and its advantages over traditional storage methods, highlighting the dual-purpose benefits of integrating renewable energy with desalination.
Summary of Using Excess Renewable Energy for Desalination as an Energy Storage Solution.
Compared to traditional electricity storage technologies such as batteries or pumped hydro, storing renewable energy through desalination offers a distinctive advantage—transforming intermittent power into a storable and essential commodity: freshwater. This dual-function approach enhances grid stability by reducing energy curtailment during peak solar or wind production while simultaneously addressing regional water scarcity. Current implementations of renewable-powered reverse osmosis (RO) plants, particularly in the GCC and Mediterranean regions, demonstrate this model’s technical and economic feasibility. By storing energy in water, the system avoids many of the drawbacks associated with electrical storage—such as degradation, material scarcity, and geographic constraints—while offering a resilient solution aligned with energy and water security goals.
Conclusion
In this study, a new approach in which the complex issues of energy storage and water security are integrated into the broader water-energy nexus is presented. A solution is proposed involving the conversion of surplus renewable energy into desalinated water, thus offering a practical approach that can meet energy storage needs while also enhancing water security, a critical factor in sustainable resource management. This approach leverages the water security-energy production nexus, recognizing the interconnected nature of the different elements and the significance of managing them in conjunction to make communities more resilient and sustainable.
To further highlight our proposed approach’s economic and environmental advantages, our findings demonstrate that desalination powered by renewable energy sources, such as solar and wind, can achieve significant cost savings. For instance, renewable-powered reverse osmosis (RO) systems in Saudi Arabia range from $1.273 to $2.119/m3, depending on the energy source and system configuration, compared to higher traditional storage costs. Additionally, renewable-driven systems can reduce energy consumption, with seawater reverse osmosis (SWRO) consuming approximately 3.5 kWh/m3, in contrast to thermal desalination processes like multi-stage flash (MSF), which require over 5 kWh/m3. This efficient use of renewable energy provides a financially viable solution for energy storage and addresses environmental concerns by reducing greenhouse gas emissions associated with conventional storage methods. Our approach, therefore, presents a sustainable, cost-effective alternative, particularly suited for regions with abundant renewable energy potential and water scarcity challenges.
Policy and infrastructure considerations are crucial in successfully deploying energy-to-water storage systems. Regulatory constraints such as static water pricing, lack of incentives for off-peak energy use, and restricted grid access for decentralized producers can hinder project feasibility. Moreover, physical infrastructure gaps—particularly insufficient reservoir capacity and the absence of smart monitoring and control technologies—limit the operational flexibility of such systems. To support the integration of renewable-powered desalination into national strategies, we recommend policy actions, including introducing dynamic water tariffs, grid priority for clean-energy desalination, and investment in digital infrastructure for real-time control of water production and storage. Enabling legislation that recognizes desalinated water as both a water and energy asset will be essential to advancing acceptance and scaling adoption in water-scarce regions.
The adoption of such a strategy will involve a paradigm shift, where relevant parties should no longer consider energy storage and water production to be distinct problems, recognizing the opportunities available if they are addressed in combination. Holistic solutions can be devised to increase the resilience and sustainability of communities. By addressing two problems together, both water and energy security can be enhanced while also contributing to efforts to meet worldwide sustainability targets, providing a potentially effective solution for regions in which water is limited and the energy supply is inconsistent. Overall, this approach demonstrates how creative thinking can generate practical solutions to resolve the complicated issues confronting the evolving world.
Future Recommendations
Future studies could explore integrating advanced renewable energy technologies, such as combining solar and wind, with innovative desalination processes to enhance efficiency and scalability further. Additionally, future research could focus on region-specific adaptations, optimizing systems for diverse climates and resource availability. Investigating the environmental impact of brine management and developing cost-effective solutions for large-scale implementation will also be crucial for maximizing sustainability and global applicability.
Footnotes
Author Contributions
Aiman Albatayneh conceptualized the research idea, supervised the project, and coordinated the overall writing and revision process. Murad Al-Omary was responsible for the methodological framework, data analysis, and drafting sections related to renewable energy integration. Mohammed Wedyan contributed to the environmental assessment and literature review on desalination technologies and water scarcity. Mohammad Aljarrah focused on the techno-economic evaluation, case comparisons, and refining the analysis of energy storage strategies. All authors reviewed and approved the final version of the manuscript.
Funding
The authors received no financial support for the research, authorship, and/or publication of this article.
Declaration of Conflicting Interests
The authors declared no potential conflicts of interest with respect to the research, authorship, and/or publication of this article.