A recent news story, Catching Waves, details how a new green energy source seeks to capture untapped energy sources in oceans and rivers.
The potential for harnessing ocean waves, currents and tides to produce electricity is vast.
The technical potential for ocean wave power in the U.S. is 90,000 MW, according to estimates by the Electric Power Research Institute. If the U.S. adopted a national renewable energy standard of 25 percent, more than 13,000 MW of that potential could be realized by 2025, according to a study by Navigant Consulting.
Up to 10,000 MW could be feasibly extracted from the swift currents off the coast of Florida, according to Florida Atlantic University’s Center for Ocean Technology.
Ocean Power Technologies (OPT) is working hard to monetize some of this potential."
Here is an interactive on how one form of it could work.
One great thing about tidal energy -- if it can be made feasible -- is that the tides always flow, unlike the wind or solar energy. The biggest hurdles are startup capital and salt corrosion. There is also some issue with prevention of harm to marine life. However, this is a power source that needs exploring.