This project developed a small methane fermentation system. To decrease the energy consumed running the reactor, a hot spring was used to heat the reactor, which used Leftover food brought by tourists. To construct this system, we determined how much Leftover food the tourists produced, whether tourists would put their Leftover food in the reactor, and the optimum conditions for producing gas via methane fermentation without pretreating the materials. The amount of food garbage per capita per day was about 300 g, of which 50% was rice. There were 24 - 48% more Leftovers from party type dinners, females, and those older than 70 years. Of the tourists, 72% would carry Leftover food from the ryokan to the reactor, which was a 10-minute walk away. The model tests indicated that the best hydraulic retention time (HRT) was around 10 days, and it performed the same as the standard methane fermentation treatment, which included pretreatment. Using Leftover food from 20 - 30 people per day would produce >1.4 m3⁄d of methane gas, whichwould Light the gas Lamp for about 8.5 hours. This system would reduce 669 MJ of energy and CO2 in waste by 100 kg per ton.
Many power plants were damaged by the Tohoku Earthquake and Tsunami on March 11, 2011. Action for electricity saving, in tight balance of power supply and demand, is significantly important to avoid unplanned massive power outages and scheduled blackouts. We have constructed "Networking for Prevention of Blackouts," which uses regional networks to call for electricity saving in the region, in which 55 local governments had participated in summer 2011. We requested households in the network for electricity saving, when electricity demand increased more than 90% of the power supply capacity of Tokyo Electric Power Company (TEPCO), on July 15 and Aug 18, 2011. We also made an experimental study to verify the effect of this system, together with 4 local governments. According to the questionnaire survey, 67% of the households took electricity saving action at the request. We also investigated the change in total electricity consumption of households participating in the study. The result showed that households have decreased power consumption by 6 - 10%, at the time of peak consumption in the jurisdiction of TEPCO. The effectiveness of the network shown by this study indicates that it is important to extend it and to pursue steady implementation for the achievement of the electricity-saving society without hampering economic activity.
This paper presents operation and the characteristics of electric power generation of a spark-ignition engine fuelled with biogas produced through a low-temperature biomass gasification process. The biomass resource was mixture of pig manure and wood chips. Two kinds of load was connected to the generator, one was electric resistance and the other is Ni-MH battery manufactured by Kawasaki Heavy Industry Co. The engine was successfully operated at the maximum BMEP (Brake Mean Effective Pressure) of 0.38 MPa which was 65 % of the original gasoline. The generation efficiency was more than 26 %, which was even higher than that of gasoline. The power could also be charged to the battery, but the BMEP and generation efficiency were 0.19 MPa and 15 %, respectively, which were pretty lower than those of resistance.
Effects of delignification treatment on the enzymatic saccharification of grass biomass (rice straw and sugarcane bagasse) were investigated. The delignification treatment improved the efficiency of the enzymatic saccharification. The yields of glucose and xylose from the delignified rice straw by enzymatic saccharification at low cellulase loading (2 FPU/g-substrate) were 75 and 65 %, respectively. Furthermore, combining delignification and hot compressed water treatment at 140°C, the yields of glucose and xylose was increased to 95 and 80 %, respectively. On the other hand, the yields of glucose and xylose from the sugarcane bagasse combining delignification and hot compressed water treatment by enzymatic saccharification were 55 and 70 %, respectively. It is shown that the high cellulase loading (10 FPU/g-substrate) was needed for obtaining high monosugar yield from sugarcane bagasse.
The feasibility of bioenergy utilization for sustainable agriculture in Asian economies was evaluated by investigating several plants in Thailand, analyzing their flow of mass, energy, and money, and evaluating the sustainability of the process. Five plants in total for biomethanation and ethanol production were studied, and the following conclusions were obtained. The two technologies investigated in this study, namely small-scale biomethanation from cattle manure and kitchen waste, and large-scale ethanol production from agricultural crops, are both effective for improving the farmers’ living standard. They can also be effective in terms of sustainable agriculture since they lead to reduced use of fossil fuel in rural areas. With regard to a small-scale biomethanation plant, the key point to success is its simplicity. On the other hand, detailed life cycle assessment (LCA) calculation is needed for ethanol production. The LCA effectiveness of ethanol production is still a controversial matter throughout the world and requires further detailed study. Reduction in biodiversity, e.g., the number of species in the environment, is to be prevented when a new crop is introduced. What is important for disseminating these technologies are farmers’ accessibility to biomass utilization or collection sites and education, e.g., providing the farmers with proper information on the technologies.