Recently, it has been reported that in the lifecycle greenhouse gas (GHG) emissions of palm oil derived biodiesel, Palm Methyl Ester (PME), direct land use change process is one of the important factors. Since most previous researches were targeted on direct land use changes from tropical rain forest to oil palm plantations in Indonesia or Malaysia, in this study, especially targeted on Thailand case, lifecycle emissions of PME including direct land use changes from rubber, tropical fruit plantations and paddy are also estimated. The lifecycle emissions are estimated at 1.01 (Degraded land), 0.64 ± 1.45 (Grassland), 7.68 (Rubber), 4.39 (Mixed orchard), -2.20 (Paddy), 12.53 ± 1.55 (Tropical rain forest), 13.08 ± 7.03 (Tropical lowland forest), 31.39 ± 2.75 (Tropical rain forest (Peat)), 23.66 ± 12.05 (Tropical lowland forest (Peat)) tCO2e/tPME. Even though these estimations are based on limited data, it is indicated that PME production including conversions from rubber, tropical fruit plantations and paddy to oil palm plantation may have less lifecycle GHG emissions than the cases of tropical rain forest conversions, and also indicated that lifecycle emissions of the cases except for conversions from degraded land, grassland and paddy are higher than that of petroleum diesel (3.25 tCO2e).
We developed the scheme of profitability analysis of a microgrid. The scheme consists of 5 processes. The first process is to calculate the optimal sizing of energy supply system in a microgrid by solving Mixed Integer Non-Linear Programming by using The General Algebraic Modeling System (GAMS). The second one is to determine the distribution of system equipment by taking space in each area into account. The third one is optimal operation planning of energy system by taking thermal transfer among areas into account. The forth one is to design electric equipment. The fifth one is evaluation of pay-back time, reduction rate of primary energy consumption and that of carbon dioxide emission. By using this scheme we also evaluate pay-back time about construction of a microgrid consisting of 3 existing District Heating and Cooling areas in Tokyo. We found that construction of a microgrid consisting of 3 DHC areas needs 8 years for recovery of investment, can reduce 26% of primary energy consumed in existing DHC areas, and can reduce about 40% of carbon dioxide emitted from existing DHC areas.
Emissions of SOX from a 4MWth twin-bed pressurized fluidized bed combustor (PFBC) system were measured during long-term (1187 hours) operation. The PFBC consisted of two bubbling beds, A-bed and B-bed. Though both reactors were operated at the same pressure and temperature, emissions of SO2 differed between two reactors. The limestone particles sampled from B-bed, which showed lower emission level, had more internal cracks and their particle size was smaller than those from A-bed. Basic studies of SO2 capture and calcination were also conducted using a pressurized fixed bed reactor for eight kinds of limestone. Calcination of limestone was found to increase reactivity with SO2 under elevated CO2 partial pressure conditions higher than equilibrium partial pressure. Limestones with more internal cracks were found to have higher reactivity towards SO2 absorption. The degree of crystallization measured by X-ray diffraction gave valuable information to predict reactivity and fragmentation. The difference in emission behavior between two fluidized beds is discussed in terms of crack formation and fragmentation.