Pulling power

The energy stored in the oceans is vastly more than Man could possibly use. The oceans convert the gravitational forces from the celestial bodies into mechanical energy, felt by the sea as it bulges to form the ebb and flow tides.

This kinetic energy can be transformed following similar rotor/turbine principles used to extract energy from the wind. Seawater is 800 times denser than air, therefore the energy available across a representative cross-section is also 800 times greater at the same speed. This means the swept area necessary to generate a given output from a tidal turbine will be substantially less than it is for a wind turbine.

A typical tidal current turbine might develop its rated power at little more than two m/s compared with 12m/s needed to achieve full-rated power for modern wind turbines. The logic follows that a one megawatt tidal turbine rotor would be less than 20m in diameter, compared with 60m for a one megawatt wind turbine.