“There’s been a lot of speculation about what charge might do to cloud droplets, but there’s been very little practical and detailed investigation,” says Keri Nicoll, one of the core investigators on the project. The aim is to determine if the technology can increase rainfall rates in water-stressed regions.

Nicoll’s team started by modelling the behavior of clouds. They found that when cloud droplets have a positive or negative electrical charge, the smaller droplets are more likely to merge and grow to become big raindrops.

The size of the raindrops is important, says Nicoll, because in places like the UAE which has high clouds and high temperatures, droplets often evaporate as they fall.