Swiss Device Turns Ocean Evaporation Into Electricity

Scientists just figured out how to turn one of Earth's most abundant resources into clean, continuous electricity.

Researchers at Switzerland's École Polytechnique Fédérale de Lausanne created a silicon device that harvests power from evaporating seawater. The system uses sunlight and heat to control how water evaporates, generating stable electrical current in the process.

The breakthrough builds on technology called the hydrovoltaic effect, which captures electricity as water flows over specially designed surfaces. Lead researcher Giulia Tagliabue and her colleague Tarique Anwar designed their device with an array of tiny silicon pillars arranged in a hexagonal pattern, creating spaces where seawater can evaporate while generating power.

The team discovered something unexpected. Heat and light weren't just helping water evaporate; they were actually boosting the device's electrical output in a completely different way. Heat increases the negative charge on the silicon's surface while sunlight energizes electrons inside it.

The results shocked even the researchers. Adding solar light and heat increased energy production by five times compared to evaporation alone. "This natural effect has always existed, but we are the first to harness it," says Tagliabue.

The device solves a major problem that plagued earlier hydrovoltaic systems: durability. Saltwater corrodes most materials, and heat plus light usually speeds up that damage. But the team coated their silicon nanopillars with an oxide layer that protects against chemical reactions, ensuring stable performance even in harsh ocean conditions.

The three-layer design lets researchers control and optimize each step separately. The top layer handles evaporation, the middle layer moves ions around, and the bottom layer collects electrical charge. This separation means the team can fine-tune performance at each stage.

The Ripple Effect

The technology could transform how we power small devices in remote locations. Tagliabue and Anwar envision battery-free sensor networks for environmental monitoring anywhere sunlight, heat, and water exist together.

The applications extend far beyond environmental sensors. Internet of Things devices, wearable technology, and any small electronics could potentially run on this free, renewable power source. No mining for battery materials, no toxic waste, no charging cables required.

The ocean covers 71% of Earth's surface and constantly evaporates under the sun. That's not just an energy source; it's an energy source the size of a planet. Now humanity has a way to tap into it.

The researchers published their findings in Nature Communications and continue refining the technology for real-world applications.