if less than 0.1% of the energy available in the oceans could be captured and converted into electricity, it would satisfy the present global demand

http://www.openhydro.com/envResource.html

environment: tidal resource

The world's oceans represent a vast resource of non-polluting, endlessly renewable energy.

Major tidal streams can be identified around the coasts of every continent, making this a truly global resource.

It has been estimated that if less than 0.1% of the energy available in the oceans could be captured and converted into electricity, it would satisfy the present global demand for energy more than five times over.*

OpenHydro estimates that the value of energy produced from the world's identified tidal resources should exceed €16 billion per year.