Solar panels pull in water vapor to grow crops in the desert

Using a unique hydrogel, scientists created a solar-driven system that successfully grows spinach by using water drawn from the air while producing electricity.

The proof-of-concept design described, low-cost strategy to improve food and water security for people living in dry-climate regions.

The system is composed of a solar photovoltaic panel placed atop a layer of hydrogel, which is mounted on top of a large metal box to condense and collect water.

Scientists developed the hydrogel in their prior research, and the material can effectively absorb water vapor from ambient air and release the water content when heated.

They used the waste heat from solar panels when generating electricity to drive absorbed water out of the hydrogel. The metal box below collects the vapor and condenses the gas into water. Alternatively, the hydrogel increases the efficiency of solar photovoltaic panels by as much as 9% by absorbing the heat and lowering the panels' temperature.

The team conducted a plant-growing test by for two weeks in June, when the weather was very hot. They used the water solely collected from air to irrigate 60 water spinach seeds planted in a plastic plant-growing box.

Over the course of the experiment, the solar panel, with a size similar to the top of a student desk, generated a total of 1,519 watt-hours of electricity, and 57 out of 60 of the water spinach seeds sprouted and grew normally to 18 cm. In total, about 2 litters of water were condensed from the hydrogel over the two-week period.

Scientists hope their design can be a decentralized power and water system to light homes and water crops.