The movement of the oceans, and flexing in the earth crust, also slows down earth's rotation. But we are talking milliseconds per century. [1] So, tidal power p

The movement of the oceans, and flexing in the earth crust, also slows down earth's rotation. But we are talking milliseconds per century. [1] So, tidal power plants are going to have a very small effect overall. http://en.wikipedia.org/wiki/Tidal_acceleration http://en.wikipedia.org/wiki/Tidal_acceleration