In everyday in our lives, we become more and more addicted to the energy and the amount of energy used by human increases day by day. Energy is very important for us, we use it for our daily tasks from as easy as using our electronic tooth brush to as complex as traveling somewhere by plane. 
Energy use terawatthour(wikipedi)
Change 2000-200822,5834263,15526,164
Eenergiläget in Sweden 2011 figure 49

As energy gets more and more important for human life and the energy consumption increases every year, and while there are countries that don't have enough energy and need to buy it from different countries, it becomes a really important goal and a problem to find clean and efficient sources of energy. And renewable energy sources like Biomass Power, Geotermal Power, Solar Power, Wind Power are really important because they are "renewable", and they keep the nation clean while creating the energy.
        Hydropower is also a main method of creating energy while keeping the nation clean. Hydroelectric plants basically turn the power of running water to electricity. The energy of the water depends on the speed of running and falling. The water running in a wide river carries huge amount of energy, or if the water made fall from a high point, a big amount of energy will be created.

        Hydroelectricity takes the 20% of the worlds energy consumption in 2006, as it is the most used renewable energy source in the world.(Maehlum) 

But how do we get electric out of water?
The coal-fired power plants work similar to the hydroelectric plants.In both of these systems. The power of the water turns the turbine that is connected to a metal shaft in an electric generator and turns the shaft, and the motor produces electricity.(USGS)

What are the Pro's and Con's of Hydroelectric ?
1. Renewable and endless
4.Flexible(The water flow and output of electricity can be adjusted)
5.Safe(Just water energy, not nuclear or any kind of fossil fuel)
1.Environmental Consequences
2.Expensive(Building  power plants)
3.Limited Reservoirs


Eenergiläget in Sweden 2011 figure 49 and 53