How sunlight could turn seawater into freshwater for coastal communities

A summer of extreme heat and drought around the world has been a reminder that water scarcity is a pressing issue and one that will only get worse with climate change. Already, more than two billion people worldwide lack easy access to clean water, according to the World Health Organization (WHO).

For some countries, desalination plants offer a solution – removing salt from seawater to satisfy their freshwater needs. The Middle East has the highest concentration of these in the world. But such plants, still mostly powered by fossil fuels, are energy-intensive and the process creates an extremely salty wastewater known as brine, which can damage marine ecosystems and animals when it’s pumped back into the sea.

That’s why some startups and researchers are updating centuries-old solar still technology, which uses only sunlight to purify water. While the technology is still a long way off from producing the volume of freshwater generated by desalination plants, it could prove valuable for off-grid or coastal communities….