Researchers have found a way to purify water and produce electricity from a single device powered by sunlight.
The scientists adapted a solar panel that not only generated power, but used some of the heat energy to distil and purify sea water.
They believe the idea could make a major difference in sunny climates with limited water supplies.
The lead author expects that a commercial device could be available in five years.
Clean energy and clean water are among the major challenges for sustainable development especially in emerging countries. But traditional approaches to electricity generation consume huge amounts of water. In the US and Europe about 50% of water withdrawals are for energy production.
Similarly, producing water for humans via desalination in countries with water scarcity is a huge consumer of energy. It's estimated that in Arab countries around 15% of electricity production is used to produce drinking water.
Now, researchers believe they have found a way to combine these actions in a single device.
Existing state-of-the-art solar panels face physical limits on the amount of sunlight they can actually turn into electricity. Normally about 10-20% of the sun that hits the panel becomes power. The rest of this heat is considered as waste.
In this experiment, the scientists designed a three stage membrane distillation unit and attached it to the back of the photovoltaic (PV) panel.
The membrane essentially evaporates seawater at relatively low temperatures. The researchers were able to produce three times more water than conventional solar stills while also generating electricity with an efficiency greater than 11%. This meant the device was generating nine times more power than had been achieved in previously published research.
"The waste heat from PV panels has really been ignored, no one has thought about it as a resource," said lead author Prof Peng Wang from King Abdullah University of Science and Technology in Saudi Arabia.
"We use the heat to generate water vapour that gets transported across the membrane and then it condenses on the other side."/BBC news