The study evaluated the biomass cogeneration system (BCGS) and the biomass steam generation system (BSGS) from the viewpoints of CO2 emissions reduction and the profit of the project. The energy, cost and CO2 emissions of BCGS and BSGS for an industrial user were predicted by simulation. The effects of the cost and CO2 savings were estimated by the comparison with a conventional system that was consisted of the grid electricity and oil boilers. The profitability of the system was evaluated by the net present value (NPV) and the internal rate of return (IRR). The results showed that the BCGS produced a larger NPV, while the BSGS had a higher IRR. It was also found that the BCGS could mitigate the risks on the profitability caused by the fluctuation of the energy prices.
In China, since the 1990's, as household incomes have increased, many kinds of appliances have been purchased, causing the electricity demand to grow from year to year. Widely-used air conditioners and recently penetrated water dispensers, in particular, contribute mainly to increased electricity consumption in the household sector. In this context, we conducted a study to provide descriptive information on the effects of this recent electricity consumption of installed air conditioners, refrigerators, water dispensers, and the standby power of electric devices of urban households in Guangzhou based on the result of our survey in 2004. The result of this study suggests that in terms of water dispensers extending operation time is a serious factor affecting increased electricity consumption. Moreover, replaced air conditioners for power saving may not be enough to reduce the growing electricity consumption.
Cellulosic energy crop has been expected as a feedstock of second generation biofuels which can avoid the competition with food production. However, concern about impact of land use change still exists, for cultivation of cellulosic energy crop requires vast land area to supply biofuel as an economically-viable alternative energy source. Therefore, this study evaluated the greenhouse gas (GHG) emission by land use change (LUC) from marginal land to plantation of cellulosic energy crop such as grass crop and fast wood forestry. First, the GHG emissions by LUC were estimated by using default value which was set based on IPCC methodology and literature review. Five warm temperate and tropical climate regions were selected in this paper. The results showed that the GHG emissions by LUC were estimated to be -5.3~10.4 g-CO2eq/MJ for grass crop and -2.3~5.6 g-CO2eq/MJ for fast wood forestry. The minimum emissions were observed in climate zone of warm temperate dry, whereas the maximum emissions were observed in tropical wet. The maximum emissions were accounted for 13 % of GHG emission by gasoline use. Finally, this study discussed the condition of biomass carbon stock for the previous land use to archive 50% GHG reductions from gasoline use.
The results of the research on combustion of granular agricultural wastes (straw) in a fluidized bed formed by granules and solid products of their combustion are introduced. The proposed technology allows to prevent slag and ash agglomeration in a bed which usually obstructs the normal work of a boiler when we use known burning technologies (in a dense bed and fluidized bed of an inert material). The researches are carried out in accordance with the results of the analysis of statistical characteristic variations of pressure drop pulsations in a bed and it allows to diagnose slagging in a bed at an early stage of agglomerate formation.