MIT engineers have developed a solar-powered desalination system that adjusts to changes in sunlight without requiring batteries. This innovation provides a sustainable solution for producing clean water from brackish groundwater, particularly beneficial for inland and remote communities.
MIT engineers have unveiled a pioneering desalination system that leverages the power of the sun to produce clean water without the need for batteries. This innovation could be a game changer for communities lacking reliable access to fresh water sources and grid power.
The new system dynamically adjusts its desalting process to match fluctuations in solar energy throughout the day. As sunlight intensifies, the system increases its water purification rate. Conversely, it scales down during cloudy intervals and ramps up once the skies clear.
By immediately responding to changes in sunlight, the system makes optimal use of solar energy, producing up to 5,000 liters of clean water daily. The system, tested over six months in New Mexico, utilized over 94% of the solar panels’ electrical energy, even during varying weather conditions.
“Conventional desalination technologies require steady power and need battery storage to smooth out a variable power source like solar. By continually varying power consumption in sync with the sun, our technology directly and efficiently uses solar power to make water,” Amos Winter, the Germeshausen Professor of Mechanical Engineering at MIT and director of the K. Lisa Yang Global Engineering and Research (GEAR) Center at MIT, said in a news release. “Being able to make drinking water with renewables, without requiring battery storage, is a massive grand challenge. And we’ve done it.”
The new system is particularly designed for desalinating brackish groundwater, a salty water source found in underground reservoirs. This type of water is more abundant than fresh groundwater, making it a valuable resource as fresh water reserves diminish worldwide. The technology promises to provide affordable, clean drinking water, especially for inland communities far from the coast and traditional seawater desalination plants.
“The majority of the population actually lives far enough from the coast, that seawater desalination could never reach them. They consequently rely heavily on groundwater, especially in remote, low-income regions. And unfortunately, this groundwater is becoming more and more saline due to climate change,” Jonathan Bessette, an MIT doctoral student in mechanical engineering, said in the news release. “This technology could bring sustainable, affordable clean water to underreached places around the world.”
The new system builds on previous designs aimed at flexible batch electrodialysis, a method that removes salt from water using an electric field. The researchers refined the control strategy, enabling the system to update its desalination rate multiple times per second, eliminating the need for batteries to manage power fluctuations.
“Compared to how you would traditionally design a solar desal system, we cut our required battery capacity by almost 100%,” Winter added.
In practical terms, this breakthrough means that the system can swiftly adapt to the solar power available, ensuring efficient desalination without the reliability issues and costs associated with battery storage.
The research, published in the journal Nature Water, highlights the potential of renewable energy in water purification technologies.
The team plans to further test and scale the system, aiming to serve larger communities and possibly whole municipalities. They are on the brink of launching a company to commercialize the technology.
“Our focus now is on testing, maximizing reliability and building out a product line that can provide desalinated water using renewables to multiple markets around the world,” added Shane Pratt, a staff engineer on the project.
The technology marks a significant advancement in sustainable water solutions, setting the stage for broader implementation and impact.