Underwater turbines are a technology that harnesses the power of ocean currents. They can capture the energy from deep-ocean currents.
Underwater (or tidal) turbines are a fairly straightforward concept, as far as cutting-edge energy technology goes. They are essentially windmills installed onto an ocean floor or river bed. The underwater current produced by the tides spins blades arranged like an airplane propeller. These turbines are attached to a gearbox, which is connected to an electrical generator. This produces the electricity that is carried by cable to shore.