Solar-Powered Desalination System Continue To Produce Clean Water Even Without Sunshine


Water scarcity is a critical issue affecting millions worldwide, particularly in rural communities where access to clean drinking water is limited.

In response to this challenge, scientists have developed a groundbreaking solar-powered system to convert saltwater into fresh drinking water, offering hope for a sustainable solution to waterborne diseases like cholera.

This innovative system, developed by researchers from King’s College London, in collaboration with Massachusetts Institute of Technology (MIT) and the Helmholtz Institute for Renewable Energy Systems (HI ERN), builds upon existing processes that convert saline groundwater to freshwater.

Through a process called electrodialysis, specialized membranes separate salt ions from water, which was reported in a paper published in Nature Water.

The process made fresh, drinkable water while channeling the salt into a stream of brine. What sets this new system apart is its reliance on solar power, making it more affordable and accessible, especially in rural areas where grid infrastructure is unreliable. By adjusting the voltage and the rate of saltwater flow, the system can adapt to variable sunlight conditions without compromising the production of fresh drinking water.

The team initially gathered data in the village of Chelleru near Hyderabad, India, and replicated those conditions in New Mexico. They successfully converted up to 10 cubic meters of fresh drinking water, equivalent to several bathtubs, which was enough to supply 3,000 people per day. The process continued to operate efficiently despite variable solar power caused by cloud coverage and rain.

Dr. Wei He, from the Department of Engineering at King’s College London, believes the new technology could provide significant benefits to rural communities. It not only increases the supply of drinking water but also improves health outcomes.

“By offering a cheap, eco-friendly alternative that can be operated off the grid, our technology enables communities to tap into alternative water sources (such as deep aquifers or saline water) to address water scarcity and contamination in traditional water supplies,” said Dr. He.

“This technology can expand water sources available to communities beyond traditional ones and by providing water from uncontaminated saline sources, may help combat water scarcity or unexpected emergencies when conventional water supplies are disrupted, for example like the recent cholera outbreaks in Zambia.”

In the global rural population, 1.6 billion people are confronted with water scarcity, with many relying on stressed groundwater reserves beneath the Earth’s surface.

However, globally, 56% of groundwater is saline and unfit for consumption. This issue is particularly acute in India, where 60% of the land has undrinkable saline water. Hence, there is an urgent need for efficient desalination methods to produce fresh drinking water affordably and at scale.

Traditional desalination technologies have typically depended on costly batteries in off-grid systems or grid connections, which are often unreliable and heavily reliant on fossil fuels in rural areas of developing countries.

The development of a low-cost ‘battery-like’ desalination technology eliminates the need for expensive batteries in off-grid applications, making it more affordable for rural communities in countries like India to utilize intermittent solar energy for desalination.

“By removing the need for a grid system entirely and cutting reliance on battery tech by 92%, our system can provide reliable access to safe drinking water, entirely emission-free, onsite, and at a discount of roughly 22% to the people who need it compared to traditional methods,” Dr. He said.

The system also holds promise for application beyond developing regions, especially in agriculture, where climate change is causing fluctuations in freshwater reserves for irrigation.

The team intends to expand the availability of the technology throughout India through partnerships with local organizations. Additionally, a team from MIT is planning to establish a startup to commercialize and finance the technology.

“While the US and UK have more stable, diversified grids than most countries, they still rely on fossil fuels. By removing fossil fuels from the equation for energy-hungry sectors like agriculture, we can help accelerate the transition to Net Zero,” Dr. He said.

“The next step for us is to apply this low-cost technology to other sectors, including wastewater treatment, and producing alkaline to make the ocean more alkaline to help it absorb more CO2 from the atmosphere. By taking this approach not only can we decarbonize agriculture, but wider environmental and climate benefits as well.”


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