A new device has the potential to bring clean water and solar energy to more than 1 billion people around the world who live without electricity and 844 million people who live without access to clean water.
Researchers at King Abdullah University of Science and Technology in Thuwal, Saudi Arabia shared an alternative to current water purification technologies.
They discovered a strategy to use an integrated photovoltaic (PV) solar panel distillation device to produce fresh water and generate electricity at the same time.
Unlike similar technologies, their tool would not consume as much electricity or require infrastructure that communities living in poverty do not always have access to, explained the team in the journal Nature Communications. But experts say technology alone cannot act as a silver bullet for the global water crisis.
The versatile device can be installed in dry regions clean water is most needed – 1 to 2 billion people are affected by water scarcity and most of them live in arid lands. Or it can be used in backyards and adapted for larger areas.
The researchers' invention could generate clean water that can be used to clean solar panels to remove dust particles, according to Professor Peng Wang, co-author of the research. It also has the ability to irrigate plants and crops and make desert agriculture possible, he said.
“It's an interesting application of the well-known multi-stage evaporation and low-temperature heat recovery projects of photovoltaic panels,” Ashok Gadgil, senior scientist at Lawrence Berkeley National Laboratory, told Global Citizen.
Although the researchers' creation is not the first to make use of solar distillation, they say it has the advantage of being compact and combining two types of technology that often require accessories and a large amount of land to use.
The device can be used to purify seawater contaminated with heavy metals at a higher rate than conventional solar methods for distilling water. During tests under perfect weather conditions, the solar cell's energy efficiency was around 11% according to the researchers, which is higher than previously reported by others working on similar devices.
So how exactly does the device work? First, saline, brackish or contaminated surface water is purified by passing through silicon solar cells. Then, the “waste heat” the solar cell heats the saline water that passes underneath it, the water evaporates, passes through a layer and condenses to provide clean water. The heat that heats the saline water in the silicon solar cell below it is released as a result, and this process is then repeated for the next solar cell. Finally, the purified water leaves the device and is collected.
Erik Harvey, director of WaterAid's program support unit, wonders what kind of investment would be needed to use the device to ensure water is suitable for human and other domestic uses.
"All technology requires good management," Harvey told Global Citizen, "which in turn requires a favorable political, legislative and financial environment, and that is either non-existent or weak in many places that suffer water stress."
The device's success rate also depends on having enough water available in the first place, Harvey said.
Distribution and costs are another concern for Harvey and Gadgil.
“The final test of this new technology will be the price of desalinated water,” said Gadgil. "Is this water accessible to the target population?"
The research team described several versions of the device and is still working to extend the invention while reducing costs