How it Works-
Tidal Power works like a hydro-electric scheme just much bigger. A huge dam (called a "barrage") is built across a river estuary. When the tide goes in and out, the water flows through tunnels in the dam.
Tidal Power has lots of advantages. Once you build it, its free. It needs no fuel and doesn't produce any bad gases.
It also has some disadvantages like how it only provides power for 10 hours, and there are few suitable sites for a tide barrage
Another option is to use offshore turbines, rather like an underwater wind farm. This has the advantage of being much cheaper to build, and does not have the environmental problems that a tidal barrage would bring.
Summary- As you can see there are many advantages and disadvantages with tidal power. Tidal power is free once you've built it. It doesn't need any fuel and it doesn't produce any bad gasses. But it only lasts 10 hours a day and there are few suitable sites for a tide barrage.
Work Cited- http://www.darvill.clara.net/altenerg/tidal.htm http://www.fansshare.com/gallery/photos/16190485/obama-sad-face-face/?displaying http://clipartall.com/clipart/62-happy-face-clipart.html http://www.alternative-energy-tutorials.com/tidal-energy/tidal-energy.html http://www.tutorvista.com/content/physics/physics-ii/fission-and-fusion/tidal-power.php