Tidal energy is a green technology that uses the tides to produce energy. The tides drive the turbines that run generators that produce energy. The reason why the tidal turbines are so green, is because they get the energy that they convert into electricity from the tides, which are caused by the moon. Indirectly the tidal turbines get their energy from the moon.

These tidal energy barges are the most common form of tidal energy generators. Tidal barges produce energy using the same concept as hydroelectric dam. It stores the incoming tide in the enclosed basin behind then dam. Then after the tide has dropped the water is released through turbines. Those turbines produce electricity when the water is flowing in and when the water is flowing out

The tidal turbine is another form of tidal energy generators. This technology is better for the environment because one doesn't have to build a dam to store the water. Instead the turbine is placed at the bottom of the ocean , so only the very tip is out of the water. The structure under water it essentially like a wind turbine, except it is under water.

These are the two different ways to produce tidal energy.

It can be created with barges (left picture) and tidal stream turbines (right picture).