According to the data collected by the Federation of Electric Power Companies of Japan (FEPC), Japan’s base-load electricity mainly focuses on Hydropower (inflow type) and nuclear power. Coal-fired and gas-fired power would belong to medium-load electricity and Fuel oil and other energies would be categorized in peak-load electricity. Ever since the Fukushima nuclear disaster, most of the nuclear power plants have been suspended, which has lowered the usage of nuclear power from 33% in 2010 to 2.15% in 2012. The power shortage caused by the decline of nuclear power has been filled by thermal power generation. According to the statistical data, the top ten power companies have significantly increased the usage of thermal power generation from 59.05% in 2010 to 89.82% in 2012, which caused Japan to import large quantities of coal, oil, natural gas and other fuels.