The first solar-powered boat is already navigating rivers in the Brazilian Amazon. Weighing 250 kilograms and a capacity to carry four people, the Siesuí 1 serves a hotel on the Araçá River in the northwestern state of Amazonas. In November, it will be replaced by the Seisuí 2, which can carry 10 people.

“The benefits are in the fuel savings and the elimination of carbon dioxide emissions,” Fernando Garcia, the inventor and builder of the boats, told Tierramérica.

These watercraft travel at 25 kilometers per hour, like the usual motor boats used in the region, but are quieter and lighter because of their aluminum shell.

The system, which includes an electric motor, stores solar energy to be able to navigate at night or on cloudy days. If the motor fails, the Seisuí has a small backup that runs on alcohol.