Suwardi and his fellow researchers have now done what once seemed impossible, pulling energy literally out of thin air. Scientists from the Chinese University of Hong Kong (CUHK) and the National University of Singapore (NUS) have designed a tiny device that converts the heat from airborne moisture evaporation directly into electricity. This isn’t a wholly new approach; a burgeoning field known as “ hydrovoltaics ” similarly aims to transform moisture into energy. Evaporation systems typically convert moisture into mechanical energy, and then into electricity, but this method could be more efficient, Suwardi’s team found. However, even sweat could potentially be used as an extra energy source, he says.