MIT develops a solar desalination system without the need for batteries

MIT researchers have developed a solar-powered desalination system that operates without expensive batteries, delivering up to 5k liters of water daily, according to research published in Nature. The plant efficiently adapts to sunlight changes, utilizing over 94% of the solar energy generated in its New Mexico test run.

Why it matters: Unlike traditional solar-based desalination methods that require a steady power connection or batteries to accommodate solar power’s natural fluctuations, this system is automated to adapt to variations in sunlight and uses electrodialysis to ramp up the efficiency of salt ion removal. This approach is ideal for remote areas with limited power connections that rely on brackish groundwater – which is increasingly saline due to climate change.

Applications for MENA: Scaling up this technology could address the region’s severe water scarcity by offering a sustainable, cost-effective desalination solution where desalination is energy-intensive and still dependent on traditional solar power. The Middle East urgently needs climate-resilient solutions, as crop yields could fall by up to 30% by mid-century.

By the numbers: Desalination costs have dropped by 60% over the past decade to around 37 cents per cubic meter, while renewable energy costs have declined by two-thirds as of 2024, making desalination and renewables more at synergy. Plant capacities have also increased to 1 mn from 600k cubic meters in five years, significantly reducing desalinated water costs.

Progress in the field: Saudi Arabia’s Moaj and Singapore’s MediSun have invested USD 30 mn to manufacture MediSun’s WEGen technology, which uses Reverse Electrodialysis (RED) to enhance energy efficiency by 30%.

Water scarcity is still an issue: While desalination is growing more energy-efficient, water stress is still an issue as the global water demand is expected to rise 10-15% due to regional conflicts, tech sector growth, and population increases, doubling the market in 4-5 years, Cox CEO Nacho Moreno told the Financial Times earlier this week. Some countries are feeling the pinch more than others, like Morocco, whose water reserves’ filling rates are down to 27.9% in August, compared to 31-32% last year, amid five years of drought.