What happens if you run an electric motor backwards? In short, it stops being a motor and becomes a generator. Following this principle, researchers at the University of Southampton have built a new ...

Computer simulation of Verdant Power's tidal turbines in action. (Note: video has no audio track.) Video courtesy of Verdant Power (1:00).

Tides are predictable years in advance, unlike wind or sunlight. Because of this reliability, harnessing the energy of ocean tides has long appealed to engineers. The difficulty lies in building ...