On July 9, 2007, Chiba University and the Institute of Sustainable Energy Policies (ISEP) released the statistics for 2006 regarding the supply of electricity from renewable energy sources for each region of Japan. The statistics showed that the household electricity demand in 76 municipalities was completely satisfied by renewable energy sources, and that more than 20 percent of the demand in four prefectures was covered by renewables. They also indicated that in nine prefectures, the percentage of renewable energy sources used to provide electricity to households was one percent or less.

Of the renewable energy sources that generate electricity in Japan, micro-hydropower (using conduit-type power generation systems with a capacity of 10,000 kilowatts or less) accounted for 59.8 percent, followed by geothermal power (18.1%), wind power (12.4%), solar power (6.0%) and biomass (3.7%). Overall, renewables represented 3.35 percent of total national household electricity demand.

The top four prefectures that actively used green energy sources were Oita, in which 30.8 percent of household electricity demand was covered by geothermal and micro-hydro power, Akita with 26.3 percent (geothermal, micro-hydro and wind power), Toyama with 23.4 percent (micro-hydro power), and Iwate with 20.2 percent (geothermal, micro-hydro and wind power). Meanwhile, towns or villages that generated more than 10 times as much green power as their respective electricity demand were Yanaizu Town in Fukushima, Kokonoe Town in Oita, Kuni Village in Gunma, and Higashidori Village in Aomori.

Chiba University and the ISEP suggested that more attention should be paid to micro-hydropower, which can be produced by making good use of Japan's steep topography and abundant precipitation, and that urban municipalities with high energy demand should help promote the use of renewable energies by such measures as purchasing "green power certificates."