Desalination meets renewables: Designing climate-resilient water systems

Rapid population growth and urbanization are increasing pressure on water systems, while climate change amplifies water scarcity. Desalination offers a pragmatic path because seawater availability is effectively limitless, but the approach needs adjustment: next generation plants need to be climate resilient, powered by renewables, engineered for ultra-low energy — pushing toward <2 kilowatt hours per cubic meter (kWh/m³) — and built with credible strategies for brine management. 

In the Middle East, particularly in the United Arab Emirates (UAE) and Saudi Arabia, seawater desalination plays a central role in national water supply strategies, supporting growing populations and long-term development ambitions. As desalination capacity expands, managing the concentrated brine produced during the process is becoming an increasingly important challenge due to its environmental impacts, additional operational energy implications and disposal requirements.

There’s growing interest in emerging approaches that can reduce the impact of brine discharge while improving overall system efficiency. One such area is brine valorization, which aims to recover valuable minerals and materials from desalination concentrate streams to support more circular water systems. While promising in niche applications, higher energy penalties and complex processing requirements alongside limited market demand mean that brine valorization alone is unlikely to absorb the large volumes generated by major desalination plants.  

In the near term, more practical and scalable pathways include robust brine discharge design, selective resource recovery and process optimization to enable higher water recovery rates. At the same time, the integration of solar power with desalination systems offers a sustainable and efficient solution for arid regions with high solar intensity, particularly when combined with battery storage to maintain operation during periods of low sunlight. 

Why desalination? 

While desalination is a water scarcity solution globally, its importance is particularly pronounced in regions such as the Middle East, where it underpins the majority of municipal water supply. 

Desalination is no longer the last resort — it has become a pillar in national water resilience strategies. The urgency to integrate desalination into national water supply strategies is shaped by a set of reinforcing climate, demographic, geopolitical and economic factors. In markets such as Saudi Arabia and the UAE, desalination already underpins municipal water supply and continues to evolve as part of broader water strategies, including reuse, storage and network optimization. 

While desalination comes with significant capital and operational costs, the economic risks of water scarcity are far greater. Disruptions to agriculture, public health systems, tourism, industry and energy infrastructure can impose losses that vastly exceed the cost of building and operating desalination plants. In this context, desalination functions as economic insurance, stabilizing national development trajectories by ensuring supply reliability. 

Advances and limits in seawater reverse osmosis efficiency 

Seawater reverse osmosis (SWRO) is the dominant desalination technology used today. In an SWRO system, seawater is pumped at high pressure through semi-permeable membranes that allow water molecules to pass while rejecting dissolved salts and impurities. The applied pressure must exceed the natural osmotic pressure of seawater, enabling the production of low total dissolved solids (TDS) permeate suitable for potable or industrial use. 

In recent decades, SWRO technology has achieved substantial performance improvements: membranes now offer higher permeability and lower energy demand while maintaining salt rejection, pre-treatment systems are far more stable and major pumps and energy recovery devices operate at extreme high efficiencies. These improvements have substantially reduced specific energy consumption and have also brought the industry close to the thermodynamic limits. Because the process must still overcome the osmotic pressure of seawater to produce low TDS‑permeate, further reductions through mechanical efficiency alone will be incremental rather than transformational. 

As continuous flow reverse osmosis (RO) nears its efficiency ceiling, batch and semi batch systems, long used in brackish and industrial treatment, together with technologies like electrodialysis, may offer pathways to further reduce energy consumption and potentially improve water recovery. 

Renewables: essential but not sufficient 

Renewable energy integration represents a strong pathway to decarbonize desalination. Yet these resources remain location dependent and utilities integrating them at scale typically require backup systems, grid connections or battery storage to ensure continuous RO operation. This makes renewables essential for sustainability, but not sufficient on their own to deliver the next major step-change in energy performance. 

The next frontier: AI driven operational optimization 

A significant opportunity for further performance improvement lies in AI-driven operational optimization. Unlike mechanical upgrades, digital optimization reduces avoidable energy losses and chemical consumption, as well as unplanned downtime by optimizing the plant as a dynamic system rather than a collection of static components. 

Seawater as a stable, reliable source 

While freshwater resources are increasingly vulnerable to climate variability and long-term overuse, seawater along coastlines is effectively constant, making it a dependable supply for coastal cities and industries. However, its viability depends on how effectively energy consumption, environmental footprint and brine discharge are managed.  

These challenges underline why next-generation plants must focus on higher efficiency and advanced process design, while ensuring responsible marine stewardship. By combining renewables, next generation process configurations and AI driven operations, utilities can deliver climate-resilient, cost-optimized desalination and reliable supply at lower energy and lifecycle cost. 

Why desalination alone is not enough 

Despite efficiency gains, seawater desalination remains the most energy- and chemical-intense solution to producing drinking water.  

The environmental footprint of desalination is higher than other water treatment methods. 

Desalination plants are mainly coastal and sometimes far from centers of population (especially in the Middle East). The energy requirement of pumping into supply can be higher than the energy required for desalination. 

The large-scale adoption of water reuse requires much less energy and the product can be used locally to preserve drinking water supplies. 

For any water utility, a balanced approach that combines desalination with other supplies will be key to ensuring long-term sustainability, resilience and operational efficiency.