Tidal power harnesses the energy from ocean tides and converts it into electricity. It works by using turbines that are turned by tidal currents flowing in and out during changes in tide levels. Tidal barrages take advantage of the height difference between high and low tides to generate power, while dynamic tidal power seeks to exploit both potential and kinetic tidal energies. The United Kingdom has invested most heavily in tidal power technologies, while Spain has some tidal power plants operating in Galicia and southwestern Andalusia.