China's Solar-Powered Desalination Prototype Achieves Zero Utility Energy Costs

Desalination has always been an energy-hungry way of turning salt water into fresh water, making it largely the preserve of wealthy countries with abundant fossil fuel reserves. Yet, an outdoor demonstration prototype in China has managed to exhibit year-long stability with zero utility energy costs, thanks to a new type of photothermal material. Experiments showed that the structure achieved a solar absorption rate of as much as 90.2 per cent, while cutting the energy needed to evaporate the same volume of seawater by 45.7 per cent. At a small trial site, the device was successfully used for desalination, helping to irrigate 5 square metres (nearly 54 square feet) of farmland for a full growth cycle using only natural sunlight and requiring no external power grid infrastructure. Based on a projected two years of operation, the team noted that the cost of producing water would fall below that of bottled water and that the economic advantage “would become even more pronounced if the system were scaled up or used over the long term”.