The electricity generated by Iran\'s hydroelectric power plants has increased 20% in the current year, an Iranian official announced on Sunday. \"The power generation of hydroelectric power plants in the water year of 1391-1392 (fall of 2012 to fall of 2013) stood at over 12,500kw/h which shows a 20% growth compared to the same period in the last water year,\" Managing-Director of Iran Water and Power Resources Development Company Seyed Mohammad Reza Rezazadeh told FNA today. Asked about his assessment and prediction for the volume of power generation in the new water year in Iran, he said rough estimates show a good trend, but everything depends on the amount of waterfalls in the fall and winter. Hydroelectricity is the term which refers to electricity generated by hydropower; the production of electrical power through the use of the gravitational force of falling or flowing water. It is the most widely used form of renewable energy, accounting for 16 percent of global electricity generation – 3,427 terawatt-hours of electricity production in 2010 and is expected to increase about 3.1% each year for the next 25 years. Hydropower is produced in 150 countries, with the Asia-Pacific region generating 32 percent of global hydropower in 2010. China is the largest hydroelectricity producer, with 721 terawatt-hours of production in 2010, representing around 17 percent of domestic electricity use. The cost of hydroelectricity is relatively low, making it a competitive source of renewable electricity.