Like millions of other people on the planet, inhabitants on the Guajira Peninsula, a coastal desert at the northernmost tip of South America, lack adequate access to electricity. Something they do have in abundance, however, is saltwater — a commodity that is now charging small lanterns used by residents in the area.

Called WaterLight, the invention consists of a handheld device designed to be filled with about two cups of ocean water, whose electrolytes react with magnesium in the light to generate a simple reaction that creates electricity.

“With one charge, it can be used for around 45 days, depending on how much you use it,” says Pipe Ruiz, executive creative director for Wunderman Thompson Colombia, a creative agency that created the lamp in partnership with green energy startup E-Dina.

When the light needs another charge, it gets refilled with water. As a bonus — because the process separates salt from water — the seawater can then also be used for cooking. The light lasts for about 5,600 hours, or two to three years of use, and is recyclable at the end of its life. Compared to a solar-powered lamp, the lantern charges instantly when water is added to it.

In remote coastal areas that still lack access to electricity, children could use the light to study, while craftspeople can use it to work. On the Guajira Peninsula, members of the Wayuu tribe who are testing the devices have been using them on boats to fish at night. The lantern also acts like a battery that can be used to slowly charge a phone or a small radio.

Eventually, the creators plan to partner up with NGOs and governments to help distribute the lights to other poor, off-the-grid coastal communities. “We see that millions of people around the world are without access to electricity on the coasts,” says Ruiz. “But actually they do have access to the oceans.”

Image source: Wunderman Thompson Colombia