Tidal energy comes from the rising and falling of oceanic tides, where water moves because of the gravitational relationship between the Earth and the moon. The Earth's rotation is also a component of tidal energy. Tidal power is a promising form of energy because it is renewable and widely available.
Three main methods of generating tidal power exist: a tidal steam generator, a tidal barrage and dynamic tidal power. A tidal stream generator harvests the kinetic energy from moving water to power turbines, while a tidal barrage exploits the potential energy in the height difference between a high tide and a low tide through a system of dams. Dynamic tidal power is a theoretical model that combines aspects of the previous two systems.