Desalination, the process of extracting salt from seawater, has long been a lifeline for many water-scarce countries, particularly in the Middle East, where freshwater is scarce, and demand is rising. Traditional desalination methods are notoriously energy-intensive, a costly trade-off for nations striving to reduce their carbon footprint.

Most desalination plants in the Middle East operate using cogeneration, where electricity and water are produced simultaneously through thermal processes. While effective, these systems are highly energy-consuming and contribute significantly to carbon emissions. In the Gulf Cooperation Council (GCC) countries alone, about 50% of primary energy is consumed for cogeneration-based power and desalination plants, according to the International Desalination Association.

Modern alternatives such as reverse osmosis offer greater energy efficiency, but the real game-changer lies in integrating renewable energy into the process.

In 2023, researchers at the University of Illinois Urbana-Champaign demonstrated the integration of solar energy into an electrochemical separation process to purify water. They said the discovery opens doors to potentially power such applications entirely with renewable energy sources.

One of the primary benefits of renewable-powered desalination is the potential for cost savings. While the initial capital expenditure for solar infrastructure can be substantial, the long-term operational costs are significantly lower compared to conventional desalination methods.

For instance, Saudi Arabia’s NEOM project is developing a fully solar-powered desalination plant utilizing “Solar Dome” technology, aiming to produce water at just $0.34 per cubic meter, which is considerably cheaper than traditional reverse osmosis plants. Similarly, research indicates that solar-driven reverse osmosis can achieve energy savings of up to 75% compared to conventional methods.

Sustainability an Imperative

With global water demand expected to soar by 55% by 2050, sustainable desalination is no longer a choice but a necessity, and governments in the region are exploring ways to further harness solar and wind for water production. Saudi Arabia has brought forward its Vision 2030 target of generating 9.5GW of renewable energy to 2023, where a substantial part of that capacity will be used to power desalination plants.

The stakes are particularly high in the UAE, where more than 90% of drinking water comes from desalination. The country has been testing the viability of renewable-powered desalination since 2013.

Masdar’s Renewable Energy Desalination Pilot Program in Abu Dhabi explored energy-efficient desalination technologies, showing that solar-driven reverse osmosis could cut energy consumption by up to 75% compared to conventional methods.

As a result, Dubai is expecting to be home to the world’s largest solar-powered desalination plant by next year, a move that could redefine how the Middle East secures its water supply. The Hassyan desalination plant with an $875 million investment is set to produce 818,000 cubic meters of potable water per day. It is Dubai’s latest step in balancing the urgent need for water security with its long-term sustainability ambitions.

In Oman, TotalEnergies and Veolia announced plans in 2022 to build a solar photovoltaic system to power the Sharqiyah desalination plant, a critical water source for 600,000 people. Egypt and Qatar have followed suit, integrating renewables into their desalination strategies as part of broader efforts to cut emissions.

The Global Clean Water Desalination Alliance has set a goal for 20% of new desalination plants to be powered by renewables between 2020-2025. Globally, the current share of renewable energy used in desalination is around 1%.

While other forms of renewables such as wind, wave, geothermal and hydroelectricity have been linked to desalination plants, the potential for solar remains high due to its abundant availability and cost-effectiveness.

PV-Based Reverse Osmosis

There are two primary types of solar-powered desalination: Concentrated Solar Power (CSP) and Photovoltaic (PV). CSP generates direct heat, typically used in thermal desalination to evaporate water, while PV uses solar panels to produce electricity, powering pumps for reverse osmosis. The World Bank has highlighted that PV-based reverse osmosis solar desalination is the leading choice and the main focus of ongoing research.

Sunny, arid regions, which are most in need of desalination, are abundant in solar power. These areas often have vast desert or wilderness spaces suitable for building new plants. Applied Water Science notes that approximately 75% of thermal desalination sites are in the Gulf countries, with half of them located in Saudi Arabia.

Although thermal desalination powered by CSP is generally less efficient than reverse osmosis, it is more effective at treating highly saline water, which can reach concentrations of 45 to 50 grams per liter.

Most solar desalination projects are currently small to medium in scale but are expanding. To date, the largest PV desalination plant, located in Saudi Arabia, is Al Khafji. It was commissioned in 2017 and produces 60,000 cubic meters of potable water daily through reverse osmosis.

A significant challenge in renewable-powered desalination is ensuring a consistent energy supply, given the intermittent nature of solar power. Advancements in energy storage and smart technologies are pivotal in overcoming this hurdle.

Modern desalination plants are increasingly incorporating advanced battery storage systems to store excess solar energy, enabling operations during non-sunny periods. Also, the integration of artificial intelligence (AI) and smart grids allows for real-time monitoring and optimization of energy consumption, enhancing efficiency and ensuring a steady water supply.

For example, Trevi Systems has developed a desalination system that operates on heat generated by solar energy and is designed to incorporate energy storage, facilitating around-the-clock operation without relying on electricity or fossil fuels.

Despite its advantages, implementing solar-powered desalination faces several challenges, including high initial capital costs, technological complexities, and the need for supportive infrastructure.

A combination of public and private investment is necessary to overcome these obstacles. This is where governments can play a key role by providing incentives, establishing favorable policies, and investing in research and development to drive innovation in this sector.

Public-private partnerships (PPPs) are emerging as a key strategy to scale solar-powered desalination projects. By leveraging government support with private sector efficiency and innovation, PPPs can accelerate deployment and reduce financial risks.

For example, Abu Dhabi-based TAQA has partnered with several international firms to develop hybrid renewable desalination plants that integrate wind, solar, and advanced membrane technologies.

The expansion of solar-powered desalination will not just be an environmental imperative but an economic and social necessity in the face of a changing climate and growing populations.