The production of electric power from hydroelectric power plants started on the small scale basis. The advantage of the hydroelectric power plants is that their life is very long and there are plants having the age of 50 to 100 years and still producing power. So at present we have large range of hydroelectric power plants producing power from hundreds of kilowatts to hundreds of megawatts. There are some hydroelectric power plants that have power generation capacity of whopping 10,000 MW that single handedly meet the electricity demands of millions of people.
As per the survey carried out by National Renewable Energy Laboratory, total electric power production capacity of all the hydroelectric power plants throughout the world is 6,75,000 MW. This combined capacity can produce 2.3 trillion kilowatt-hours of electricity every year. This huge power is good enough to fulfill electricity demands of more than one billion people of the world or almost 24% population of the entire world.
Surprisingly, there are some countries where their entire demand of electricity is met by the hydroelectric power plants. For instance, in the countries like Norway and Democratic Republic of Congo, almost 99% of the electric power demands were fulfilled by the hydroelectric power plants in the year 1998. Even Brazil’s 91% of power requirement was met by hydroelectricity by the same year.
