Is hydroelectric power perfectible?

It is Electricity generated by the movement of water. Examples would be waterfalls strong rivers, and tides. The water turns a turbine which generates the electric power. On Earth, water is can't be...

Once the dam is built and the power plant installed, there are no fuel costs and no pollution

Water passing through a turbine, usually in a dam.

Its not neccessarily a bad thing, but its not a good thing either. Using water for energy can ruin habitats by flooding and not letting water flow naturally. Its better than some sources of energy...

coaled power, gas powered, wind turbines, nuclear energy, i believe are not examples of hydroelectric power