Desalination at a turning point: the search for energy efficiency
The world’s reliance on desalination has never been greater. As climate change accelerates drought conditions and freshwater sources become increasingly strained, seawater desalination has moved from an alternative solution to an essential pillar of water security.
Despite desalination’s undeniable role in ensuring supply in arid regions, it remains an energy-intensive process, with power consumption representing up to 60% of operational costs. In an era of rising electricity prices and ambitious decarbonization targets, the industry faces a pressing challenge: how to reconcile water security with energy efficiency.
To explore this question, Smart Water Magazine convened the Virtual Roundtable on Energy Efficiency in Desalination – Innovations and Sustainable Practices, held on March 4, 2025. The event gathered leading experts to address the technological breakthroughs and strategic approaches that are reshaping the industry, offering a deep dive into the solutions that can reduce desalination’s energy footprint while ensuring long-term sustainability.
The discussion unfolded through four key perspectives, each tackling a different aspect of desalination’s energy challenges. Dr Domingo Zarzo, Head of Strategic Projects and Institutional Relations at Sacyr Water & President of AEDyR, provided a global view of desalination trends, dismantling misconceptions and highlighting the industry’s progress in reducing energy consumption over the past decades.
Miguel Aritio, Director of Energy Resources & Business Development North Africa at ACCIONA, examined how large-scale desalination plants can optimize power use, leveraging renewables and energy recovery systems to minimize costs. Christos Charisiadis, Founder & Principal Consultant at Brine Consulting, introduced a sustainability-driven vision for brine management, showcasing how modern desalination can transition from waste disposal to resource recovery and circular economy principles. Finally, Jesús Rivas, Water and Wastewater Global Manager at WEG, explored the role of high-efficiency motors and digital automation, illustrating how smart process control and AI-powered maintenance can enhance desalination performance.
This roundtable served as a meeting point for ideas and innovation, connecting water professionals with the latest advancements in membrane technology, energy optimization, and decarbonization strategies. The following analyses delve into each of these expert perspectives, offering a comprehensive look at the future of energy-efficient desalination.
Beyond myths: how desalination is becoming smarter and more sustainable
Dr Domingo Zarzo opened the discussion with a global perspective on the evolution of desalination, highlighting how it has transitioned from a last-resort solution to a key pillar of water security. With 800 million people lacking access to safe drinking water and 2.2 billion facing unreliable supplies, desalination is no longer an option but a necessity. The industry has responded with rapid technological advancements, increasing efficiency while dispelling outdated misconceptions about energy use, environmental impact, and cost.
Today’s RO systems consume as little as 3 kWh per cubic metre, reducing energy consumption by a factor of 10 over the last 50 years
Contrary to widespread belief, modern desalination is far from the inefficient, high-energy process it was decades ago. Today’s reverse osmosis (RO) systems consume as little as 3 kWh per cubic metre, a dramatic improvement that has positioned the industry as one of the few to reduce energy consumption by a factor of ten over the last 50 years. This transformation has been driven by high-efficiency membranes, advanced energy recovery devices (ERDs), and AI-powered process optimization, making desalination more competitive than ever. Zarzo compared its energy use to common household appliances, noting that the electricity required to supply a family of four with desalinated water for a year is equivalent to running a refrigerator.
Another persistent myth concerns brine discharge and its impact on marine ecosystems. Zarzo emphasized that studies show salinity levels quickly return to normal just metres from discharge points, challenging the assumption that desalination poses an existential threat to marine life. When placed against the environmental footprint of other water sources, desalination proves to be far less invasive than commonly assumed.
"Desalination is one of the few industries that has reduced its energy consumption by a factor of ten in the last 50 years. The challenge now is to push efficiency even further while integrating sustainability."
Domingo Zarzo, Head of Strategic Projects and Institutional Relations at Sacyr Water & President of AEDyR
However, the industry’s progress does not mean there are no challenges ahead. While Spain, Saudi Arabia, and the UAE continue expanding their desalination capacity, the sector is approaching the thermodynamic limit of 1 kWh/m³, meaning future energy reductions will be incremental rather than revolutionary. Zarzo pointed to the importance of smart RO plant configurations, optimized pretreatment, and AI-driven automation, which allow plants to dynamically adjust pressure, flow rates, and chemical dosing in real time, further enhancing efficiency.
Decarbonization remains the industry’s next frontier, yet it comes with technical and logistical hurdles. While many nations are experimenting with renewables, large desalination plants require constant energy, making it difficult to rely solely on solar and wind without large-scale storage solutions. Some countries, such as Spain and Australia, are taking an alternative approach by purchasing renewable energy offsets, ensuring cleaner desalination without the need for direct on-site renewable generation.
When placed against the environmental footprint of other water sources, desalination proves to be far less invasive than commonly assumed
Looking ahead, Zarzo emphasized that the future of desalination extends beyond water production. The industry is increasingly embracing circular economy principles, with brine mining and resource recovery emerging as promising solutions to transform waste into valuable commodities. AI and digitalization will also play a crucial role in ensuring that desalination continues to improve, not only in efficiency but also in public perception. Initiatives such as the Water Positive Initiative, which brings together over 400 professionals worldwide, are working to offset the water footprint of industrial activity, ensuring that desalination remains a sustainable and financially viable solution for generations to come.
Zarzo left the audience with a clear message: desalination is not only an energy-efficient process — it is becoming a cornerstone of sustainable water management. Through continued investment in technology, policy innovation, and digital transformation, the industry is proving that water security and environmental responsibility can go hand in hand.
Optimizing energy at scale: the future of large-scale desalination
Miguel Aritio explored one of the most pressing issues in desalination: how to manage energy use in large-scale facilities without compromising efficiency or sustainability. With energy costs representing up to 40% of the total cost per cubic metre of water produced, it is clear that the industry must rethink its approach to power consumption. His presentation provided both a strategic vision and practical solutions, focusing on renewable energy integration, energy recovery, and process optimization to drive desalination toward a more sustainable future.
While solar and wind energy have become highly competitive, their integration into desalination remains complex due to storage limitations
His analysis highlighted the unique energy challenge of desalination — plants operate with flat, continuous consumption, requiring high-voltage energy input that does not always align with the intermittent nature of renewables. While solar and wind energy have become highly competitive, their integration into desalination remains complex due to storage limitations and fluctuating power output.
To address this, Aritio outlined three primary energy supply strategies currently shaping the industry. The first is on-site renewable energy generation, where some desalination plants are directly integrating solar photovoltaic (PV) systems, covering up to 20% of their energy demand in optimal conditions. However, land constraints often limit scalability, as each hectare of a desalination plant requires at least five hectares of PV panels to achieve this level of contribution.
"Energy efficiency is not just about reducing costs — it’s about rethinking how desalination integrates with renewable energy to ensure a long-term, sustainable future."
Miguel Aritio, Director of Energy Resources & Business Development North Africa at ACCIONA
Another approach is Power Purchase Agreements (PPAs), where desalination operators secure long-term renewable energy contracts with independent power producers. This allows them to access clean energy without requiring on-site generation. This model has been successfully implemented in Spain and Australia, where national grids facilitate renewable energy supply to desalination plants.
The third strategy involves hybrid systems incorporating energy storage. A growing number of desalination projects are experimenting with integrated battery storage and smart grid solutions to stabilize renewable power input. Hydrogen production from excess renewable energy could play a role in the long-term decarbonization of desalination.
A growing number of projects are experimenting with integrated battery storage and smart grid solutions to stabilize renewable power input
To illustrate real-world applications, Aritio presented the case study of the Jubail 3B desalination plant in Saudi Arabia, designed and built by ACCIONA. This 500,000 m³/day facility was designed to operate with 60 MWp of solar PV capacity, directly connected to the desalination plant’s transformers. This setup allows the plant to cover 20% of its annual energy needs with solar energy, maximizing self-sufficiency while ensuring continuous operation. However, as pointed out, such projects require significant land availability, with PV installations covering four to five times the area of the desalination facility itself.
Looking to the future, Aritio emphasized that desalination will play a central role in the global energy transition. As the industry moves toward fully renewable-powered desalination, new challenges will emerge—particularly regarding grid integration, large-scale energy storage, and policy support. He concluded by reaffirming that efficiency must be tackled from multiple angles: combining renewables, advanced energy recovery, smart automation, and rethinking plant design from the ground up.
From waste to resource: the transformation of brine management in desalination
For decades, desalination has been criticized for its brine discharge, often seen as an unavoidable byproduct with limited solutions. Christos Charisiadis challenged this perception, presenting a vision where brine is not waste but an untapped resource. His presentation explored how modern desalination plants are shifting toward resource recovery, transforming brine into valuable minerals while reducing environmental impact.
With the right technology, magnesium, lithium, and bromine can be extracted, turning desalination into a dual-purpose industry
The scale of the challenge is immense — 142 million cubic metres of desalinated water are produced daily, generating an equivalent volume of brine. Disposing of this byproduct through traditional methods can elevate salinity levels in marine environments and requires additional energy-intensive processes. However, Charisiadis argued that brine holds enormous economic potential if approached differently. With the right technology, elements such as magnesium, lithium, and bromine can be extracted, turning desalination into a dual-purpose industry: water production and mineral recovery.
Several real-world projects are already demonstrating the viability of this approach. In Saudi Arabia, magnesium recovery has offset desalination costs by $8-12 per cubic metre. The Dead Sea’s bromine extraction supplies 85% of global demand, while lithium, essential for electric vehicle (EV) batteries, is being recovered at commercial levels. These initiatives are proving that desalination can be a key player in the circular economy, shifting from a cost-heavy operation to one with financial returns.
"Brine should no longer be seen as a waste product. With the right approach, desalination can become a circular economy model where waste becomes a valuable resource."
Christos Charisiadis, Founder & Principal Consultant at Brine Consulting
Charisiadis emphasized that achieving this transformation requires more than just new extraction methods — it demands a rethink of desalination infrastructure. Hybrid membrane-based brine concentration systems are emerging as the most promising approach, capable of reducing brine discharge by up to 90% while significantly lowering energy consumption compared to conventional thermal methods. These systems, which combine reverse osmosis, electrodialysis, and membrane distillation, are making it possible to concentrate brine efficiently while recovering high-value minerals.
Beyond technology, digitalization is playing a crucial role. Charisiadis highlighted how AI-driven process optimization and digital twins are improving brine management by reducing energy consumption, predicting maintenance needs, and enabling real-time monitoring. In plants where these technologies have been implemented, operational costs have dropped significantly, reinforcing the case for widespread digital transformation in desalination.
Desalination can be a key player in the circular economy, shifting from a cost-heavy operation to one with financial returns
However, technology alone is not enough. Charisiadis made it clear that policy and industry collaboration will determine how quickly brine management evolves. The European Union’s Water Framework Directive is already enforcing stricter brine discharge regulations, pushing desalination plants toward resource recovery. Saudi Arabia’s Vision 2030 is accelerating investments in brine mining, while China’s Zero Liquid Discharge (ZLD) regulations are driving industries toward full brine treatment solutions. These initiatives signal a broader shift: governments are beginning to view desalination as a strategic sector, not just for water security, but for resource sustainability.
Looking ahead, Charisiadis painted a picture of desalination plants evolving into self-sustaining ecosystems, where brine is no longer discarded but fully utilized. Scaling up mineral recovery, integrating renewables into brine treatment, and developing financial incentives for circular economy initiatives will be key to this transition. His final message was clear: brine should no longer be seen as an environmental burden but as a valuable resource with economic and sustainability benefits. By aligning policy, investment, and technology, desalination has the potential to become not just a solution for water scarcity, but a contributor to the broader sustainability agenda.
Powering the future: how high-efficiency motors and digitalization are transforming desalination
In the intricate mechanics of desalination plants, motors are the silent force behind every drop of purified water. Jesús Rivas took the audience into the heart of these operations, where the energy challenge is not just about producing water — it’s about doing so as efficiently as possible. With up to 50% of desalination operational costs tied to energy consumption, optimizing motor performance is not just an improvement — it’s a necessity.
AI-driven process optimization and digital twins are improving brine management by reducing energy consumption, predicting maintenance needs
Rivas highlighted that high-pressure pumps, booster pumps, and intake systems account for the bulk of desalination’s electricity demand. Every inefficiency in motor performance translates into higher costs, greater energy waste, and increased carbon emissions. The solution, he argued, lies in next-generation high-efficiency motors — designed to minimize energy losses while ensuring consistent performance under extreme operating conditions.
WEG’s IE3, IE4, and IE6 motors, achieving efficiencies of up to 98%, are already redefining how desalination plants operate. By integrating permanent magnet motors, axial flux configurations, and advanced cooling systems, these technologies are reducing energy consumption by 20-30%, delivering not only cost savings but also a smaller environmental footprint.
"High-efficiency motors and smart automation are revolutionizing desalination. AI-driven control systems are already cutting energy use by up to 30% — and this is just the beginning."
Jesús Rivas, Water and Wastewater Global Manager at WEG
However, motor efficiency alone is not enough. Rivas emphasized the game-changing role of digital automation and AI-driven control systems. Technologies such as Variable Speed Drives (VSDs) dynamically adjust motor speeds based on demand, preventing unnecessary power consumption. Meanwhile, smart sensors and remote monitoring platforms, like WEG’s Motion Fleet Management (MFM) with AI, are anticipating maintenance needs before failures occur, ensuring plants run at peak efficiency with minimal downtime.
To illustrate these advances, Rivas shared real-world examples. In Chile’s Mantoverde SWRO plant, the deployment of W22 motors and variable speed drives led to significant energy cost reductions and lower CO₂ emissions, aligning with Chile’s broader sustainability objectives. Meanwhile, at Saudi Arabia’s Rabigh 3 IWP, one of the largest desalination plants in the world, WEG’s high-efficiency motors and advanced automation systems optimized performance so effectively that the company was awarded the Rabigh 4 contract, further cementing its role in the Middle East’s push for sustainable water infrastructure.
With up to 50 per cent of desalination operational costs tied to energy consumption, optimizing motor performance is a necessity
Looking ahead, Rivas painted a vision of desalination plants seamlessly integrating with renewable energy grids. High-efficiency motors will serve as the backbone of hybrid desalination systems, ensuring stability as plants shift toward solar, wind, and energy storage solutions. AI-powered digital twins will allow operators to simulate and fine-tune plant performance in real-time, adjusting energy use dynamically to minimize costs and maximize efficiency.
His final message was clear: desalination is not just about producing water — it’s about producing it in the smartest, most energy-efficient way possible. By embracing advanced motor technology, automation, and AI-driven optimization, the industry is moving toward a future where water security and energy sustainability go hand in hand.
Key takeaways: challenges, innovations, and the road to energy-efficient desalination
The roundtable’s Q&A session provided valuable insights into the key challenges and opportunities for improving energy efficiency in desalination. Industry experts addressed critical topics such as energy recovery technologies, the role of digitalization, the feasibility of integrating renewables, and the future outlook for desalination processes.
One of the themes discussed was the widespread use of energy recovery devices (ERDs), which have significantly reduced the energy consumption of desalination plants over the past few decades. Experts emphasized that ERDs, such as pressure exchangers and isobaric devices, have become a standard in seawater desalination. However, for smaller-scale industrial plants and brackish water desalination, the feasibility of ERDs depends on factors such as pressure levels and flow rates.
Governments are beginning to view desalination as a strategic sector, not just for water security, but for resource sustainability
Digitalization and artificial intelligence (AI)-driven optimization were also recognized as game-changers in the industry. While AI is already being used for predictive maintenance and process control, panellists suggested that future desalination plants may rely more heavily on autonomous operation, with AI-guided optimization of energy use and real-time adjustments to improve efficiency.
The potential for renewable energy integration was another topic of interest. The feasibility of geothermal energy in desalination was discussed, with experts noting that while it could be beneficial for increasing feedwater temperatures and improving membrane permeability, its economic viability remains uncertain. More broadly, panellists stressed that the successful integration of renewables such as solar and wind into desalination operations will require better energy storage solutions and smart grid integration to manage the intermittency of these energy sources.
When asked about the impact of stricter water quality regulations, particularly regarding PFAS and emerging contaminants, panellists emphasized that reverse osmosis already provides a high level of rejection for most pollutants. Therefore, they do not anticipate major cost increases in desalinated water due to new regulations.
When addressing future innovations, the panellists agreed that while incremental efficiency improvements will continue, there are no major breakthrough technologies on the immediate horizon that will drastically reduce energy consumption beyond current levels. Reverse osmosis (RO) technology has already reached a high degree of efficiency, approaching its thermodynamic limit, meaning that future gains will likely come from better system integration, smarter operational strategies, and digital advancements.
In closing, the experts underscored the importance of communication and public awareness in shaping desalination’s role in global water security. They emphasized that while desalination remains an energy-intensive process, its efficiency has improved dramatically, and ongoing technological advancements will continue to enhance its sustainability and cost-effectiveness.
The future of desalination: a net-zero vision
The roundtable reinforced that desalination is entering a new era, where efficiency, sustainability, and policy alignment will define its trajectory. While energy consumption has dropped significantly over the past decades, the next step is ensuring that desalination is not just efficient, but entirely sustainable.
Renewable integration is inevitable, but desalination’s constant energy demand poses challenges for relying solely on solar and wind. Battery storage, smart grid integration, and power purchase agreements (PPAs) are emerging as solutions, with Spain and Australia already leading the charge in low-carbon desalination initiatives.
Desalination is not just about producing water — it’s about producing it in the smartest, most energy-efficient way possible
Innovation will continue to reshape desalination, with AI, digital twins, and machine learning driving real-time process optimization. Brine valorization technologies will further transform the industry, ensuring desalination is not just about water production but also resource recovery.
The panellists agreed that policy and investment will be just as crucial as technology. Governments and financial institutions must create strong incentives for energy-efficient desalination, while private sector players must invest in low-energy solutions to make net-zero desalination a reality.
Desalination is no longer just about making seawater drinkable — it is evolving into a cornerstone of sustainable water management. With the right investments, regulatory support, and technological breakthroughs, net-zero desalination is no longer an aspiration — it is within reach.