Ocean Power

This sounds promising. Portugal is already invested in using ocean currents to generate electricity.

Telegraph.UK: Ocean currents can power the world, say scientists

The technology can generate electricity in water flowing at a rate of less than one knot - about one mile an hour - meaning it could operate on most waterways and sea beds around the globe.

Existing technologies which use water power, relying on the action of waves, tides or faster currents created by dams, are far more limited in where they can be used, and also cause greater obstructions when they are built in rivers or the sea.