China's New Solar Breakthrough Makes Desalinated Water Cheaper Than Bottled

In a time when AI data centers are using massive amounts of water, adding to a man-made crisis the United Nations calls the "Era of Global Water Bankruptcy," Chinese scientists have created a solar-powered device for efficiently turning seawater into fresh water. In a study published in the journal Advanced Materials, the researchers share how their mix of nanomaterial and tightly linked polymer chains could make desalinated water cheaper than bottled water after two years of use.

The researchers built a desalination device using their material and found the machine, which measures at around eight square feet, evaporates water at 8.5 times the rate of existing solar desalination methods. That allows it to produce a bit over five gallons of clean water each day under natural sunlight.

It's a significant breakthrough for a technology that is becoming more vital, especially for places like the Middle East, Africa, and California where fresh water is scarce. Existing desalination methods — thermal and reverse osmosis — involve a lot of energy, making them prohibitively expensive and not eco-friendly. Up to now, solar powered desalination has been less effective and hard to implement, which is why a material that can be used to efficiently produce clean, safe-to-consume water without burning fossil fuels is so promising.

While it covers most of the surface of the planet, only an extremely small percentage of Earth's water is drinkable. As demand rises, making seawater potable is becoming a crucial tool for increasing supply and keeping prices from skyrocketing — so long it can be done in a low-cost way that doesn't involve burning the same fossil fuels that led to the water and climate crises.

One area where efficient solar desalination could make a difference is in data centers. Since salt water would leave behind residue, leading to clogs and damage to equipment, the facilities eat into the already strained fresh water supply. The ability to desalinate water effectively and in massive quantities wouldn't solve all of the issues with AI data centers, but it would at least prevent them from draining local water reserves.

Desalinated water is also good for irrigating crops. The Chinese researchers behind the desalination machine used the water produced on a six-square-yard field and found it "successfully supported the full-growth cycles of various crops" including spinach, corn, and Chinese cabbage. That could make a difference in places where extreme droughts are causing failed harvests and famine.

This is far from the only effort. A University of Rochester project found a way to use laser-treated solar panels to distill seawater without leaving behind brine – concentrated salt water, minerals, and (in most cases) chemicals used to pretreat the water. Brine is often dumped into the sea or elsewhere in the environment, which can be hazardous to wildlife, groundwater, and soil quality. The University of Rochester's breakthrough allows leftover salt to be recovered in solid form, allowing it to be reused and prevent waste.