Introduction: Hydroelectric power plant is one of the major power plants in the world to create electricity. It is also one of the best sources of renewable energy on planet earth. In the ranking, Canada is the third largest country for hydroelectric energy production. The efficiency of this power source is 90% and this is very impressive as the efficiency percentage is very high. Hydroelectric power plants generate 24% of the world's electricity. More than 1 billion people are associated with hydropower plants as they use the energy provided by hydropower plants. Where does it come from? / Source:Hydroelectric power became the source of electricity generation in the late 19th century. Electricity generated by hydroelectric power plants is done simply by using moving water. Due to rain or melting snow on hills and mountains, water flows towards the earth's surface with the help of gravity. This running water is highly energized and is then used to create electricity. Not only mountains, rivers, streams and other water sources help create electricity with the use of hydroelectric power plants. The power plant converts the kinetic energy of water into mechanical energy and electrical energy. Waterfalls, lakes, rivers and streams are three natural sources of hydroelectric energy. Water that falls or flows from a waterfall or river respectively is stored directly in a dam. This dam can be opened or closed according to the need of the water level. A great example of a natural source of hydroelectric power plant would be the Niagara Falls Power Plant. This was the first hydroelectric power plant built in 1879. A man-made source could be a direct path in the direction of a dam from any natural source. S...... half of the document ...... viewed May 1, 2014, from http://www1.agric.gov.ab.ca/$department/deptdocs.nsf/all/eng4431Hydroelectric power water use . (n.d.). Hydroelectric energy and water. Hydropower Basics, USGS Water Science for Schools. Retrieved May 1, 2014, from https://water.usgs.gov/edu/wuhy.htmlHydroelectricity. (n.d.). BEE. Retrieved May 1, 2014, from http://www.epa.gov/cleanenergy/energy-and-you/affect/idro.htmlHydropower. (n.d.). THAT. Retrieved May 1, 2014, from http://che.nelson.wisc.edu/cool_stuff/energy/idro.shtml#productionHydropower. (n.d.). - Hydroelectric energy. Retrieved May 1, 2014, from http://www.renewableenergyworld.com/rea/tech/idropowerHydropower Facts, Hydropower Information- National Geographic. (n.d.). National geographic. Retrieved May 1, 2014, from http://environment.nationalgeographic.com/environment/global-warming/idropower-profile/