How can the ocean give us clean energy?

Can the ocean provide clean energy?
Can the ocean provide clean energy?
Polka Dot Images/Thinkstock

In the face of increasing energy demands and increasingly problematic energy sources, the appeal of using the ocean to generate power is obvious: Water covers more than 70 percent of the Earth's surface, and it's not going anywhere any time soon.

And, like the wind and the sun, the ocean -- its waves, tides and temperature gradations --can be harnessed to generate clean electricity, with no emissions or byproducts to manage.

Ocean energy taps into the power of interactions between oceans and the wind (wave energy), the moon (tidal energy), and the sun (thermal energy). The technologies are pretty far behind wind and solar as far as large-scale generation goes, but the potential is huge -- and growing.