Explanation:

Hydroelectricity is Japan’s main renewable energy source, with an installed capacity of about 50 GW and a production  of 69.2 TWh of electricity in 2009, making Japan one of the biggest hydroelectricity producers in the world. As of September 2011, Japan had 1,198 small hydropower plants with a total capacity of 3,225 MW. The smaller plants accounted for 6.6% of Japan’s total hydropower  capacity. The remaining capacity was filled by large and medium hydropower stations, typically sited at large dams. Japan lacks significant domestic reserves of fossil fuel, and import substantial amounts of crude oil, natural gas, and other energy resources, including uranium. Japan relied on oil imports to meet about 84% of its energy needs in 2010.