A UK-based startup, Global OTEC, is breathing new life into a century-old technology that could power tropical island nations with virtually limitless, consistent, renewable energy by treating the ocean like a battery. Ocean thermal energy conversion (OTEC) might produce at least 2,000GW globally, rivalling the combined capacity of all the world’s coal power plants.

French physicist Jacques Arsene d’Arsonval invented ocean thermal energy conversion in 1881 when he realized that the temperature difference between the surface and the cold depths of the ocean could be used to  generate electricity.  Now, says Global OTEC, innovation and partnerships can prevent the 50 million people who live on tropical islands from having to seek refuge because island life has become untenable.