Chinese Scientists Achieve Solar-Powered Desalination at Record Efficiency

Chinese researchers have developed a new solar-powered desalination technology that could make turning seawater into fresh water cheaper than bottled water, according to a report in the South China Morning Post.

Desalination has traditionally been an energy-intensive process, limiting its use largely to wealthy nations with abundant energy resources. However, scientists in China have built an outdoor prototype that operated for a full year with zero utility energy costs, relying solely on sunlight.

The breakthrough involves a newly designed photothermal material. Researchers wove nanoparticles into a three-dimensional structure that significantly improves the efficiency of converting sunlight into heat, which drives the evaporation process needed for desalination.

In tests, the material achieved a solar absorption rate of up to 90.2 per cent, while reducing the energy required to evaporate the same amount of seawater by 45.7 per cent compared with conventional methods.

At a small trial site, the system desalinated seawater for irrigation, successfully watering approximately 5 square metres of farmland through an entire growing cycle. The system required no connection to the external power grid and operated entirely on natural sunlight.

The research team estimates that, based on around two years of operation, the cost of producing water this way would drop below the price of bottled water, the South China Morning Post reported. The savings would increase further if the technology were scaled up or used over a longer period.

This innovation offers a low-cost, sustainable option for regions facing water shortages, particularly areas with strong sunlight but limited energy infrastructure, without depending on expensive power supplies or fossil fuels.