After the nuclear accident at the Fukushima No. 1 nuclear power plant, electric energy by thermal power generation using natural gas or coal increased to make up for the decrease of electric energy produced by nuclear power generation. It is well known that greenhouse gas, such as carbon dioxide, increases with consumption of fossil fuels. Therefore, enhancement of renewable energy including solar, wind, geothermal, hydro and biomass is anticipated. Among the forms of renewable energy, energy from biomass is available in cities and the suburbs. Biogas results from anaerobic fermentation of wet biomass, such as sludge, food waste and agricultural waste. Considering the case studies about methane fermentation in a regional independent society, the Tama region around Tokyo possesses potential for mixed methane fermentation with plant biomass (paper, food waste and agricultural waste) and sludge. When the mixed methane fermentation is carried out in Tama region, establishment of a regional independent, sustainable and recycling-based society with low carbon will become possible.