Strong ocean currents are generated by a combination of temperature, wind, salinity, bathymetry, and the rotation of the earth. The sun acts as the primary driving force, causing winds and temperature differences. Because ocean currents are fairly constant in both speed and flow and carry large amounts of energy, the ocean may provide a variety of suitable locations for deploying energy extraction devices such as turbines. Turbines capable of harnessing the kinetic energy of ocean currents may be indistinct from other marine current turbines and function according to the same principles. However, they may be designed or optimized for lower flow speeds relative to currents in tidal channels and may not need to account for reversing flow. A major difference is where the devices may be located—both geographically and in the water column. Strong ocean currents tend to be further offshore than tidal currents, which tend to be found in coastal or inland waters. This leads to deployment in deeper water, where a fixed substructure supporting a turbine higher in the water column where current is stronger is impractical. Devices may be suspended from moored surface platforms or attached to buoyant structures tethered to the seabed. Electricity is produced by coupling a generator to the turbine. Power is transmitted back to shore via cable.
