Marine current power the rotation of the earth. The sun acts as the primary driving force, causing winds and temperature differences. Because there are only small fluctuations in current speed and stream location with minimal changes in direction, ocean currents may be suitable locations for deploying energy extraction devices such as turbines. Other effects such as regional differences in temperature and salinity and the Coriolis effect due to the rotation of the earth are also major influences. The kinetic energy of marine currents can be converted in much the same way that a wind turbine extracts energy from the wind, using various types
Winds in the Age of Sail the Canary current which pushes him southwest down the African coast. He soon reaches the northeast trade winds which also push him southwest. If he leaves in late summer he will hit the trade winds sooner since wind systems move north and south with the seasons. The problem was to get back again. The solution was the volta do mar in which a captain would sail northwest across the winds and currents until he found the westerlies and was blown back to Europe. The coast of Northwest Africa might be described as the nursery of European imperialism. Experience gained here