Towards widespread use of solar power generation system, the intrinsic cost reduction should be essential in order to compete against conventional power generation systems. Therefore, it is necessary to clarify the priority of technology development items and directions from the stand point of the economic and environmental aspects based on scientific basis. This paper reveals cost structure of monocrystalline silicon photovoltaic power generation systems in three different technology scenarios. In this analysis, we use economic and environmental evaluation methodology called “Platform of low carbon technologies for process design and evaluation of manufacturing cost and CO2 emissions” which has been developed by Center for Low Carbon Society Strategy (LCS). As a result, the current installation cost of a monocrystalline silicon photovoltaic power generation system is 176 yen/W (18 yen/kWh) and CO2 emissions is 1200 g-CO2/ W (60 g-CO2/kWh). Two significant technology development items are indicated by this research. One is the reduction of raw material consumption and the other is the improvement of module efficiency. The manufacturing cost can fall to 105 yen/W (11 yen/kWh) in a scenario(mainly by reducing the wafer thickness 100um and improving module efficiency 20%) and 70 yen/W (7 yen/kWh) in other scenario(mainly by reducing the wafer thickness to 50 μm or less and improving module efficiency up to 23%).
We investigated the extraction of 5-hydroxymethylfurfural (5-HMF) from 1-ethyl-3-methylimizadolium chloride ([C2mim]Cl), which is produced by heating of sugar in the ionic liquid, [C2mim]Cl. It is found that 5-HMF can be obtained from sucrose at 28.8wt% of the yield by heating at 140 ºC for 10 min under microwave irradiation. For evaluating the extraction of 5-HMF from [C2mim]Cl, we determined “the degree of extraction”, which is defined as percentage of extracted 5-HMF from [C2mim]Cl, and “selectivity”, which is defined as percentage of 5-HMF in all extracted substances from [C2mim]Cl. Effective extraction at 67.3% of the degree of extraction and 99.4% of selectivity can be attained by using the mixture of hexane and acetone after adding water to [C2mim]Cl.
Bio-chars loaded directly with catalytic metals such as K and Fe were gasified with CO2 at atmospheric pressure after being heated to 1023-1323 K under an Ar flow. The gasification rate constant (Kp) of K-loaded bio char was extremely higher than that of Fe-loaded bio-char. The structure such as surface and cross section of these bio-chars after (1) metal ions were supported on bio-char by the impregnation method (i.e. before heating) and (2) heating under an Ar flow (i.e. just before gasification) were observed using scanning electron microscopy (SEM) and energy dispersive X-ray spectroscopy (EDS). Before heating, the K atoms were uniformly distributed with no crystal formation. Even after heating under an Ar flow, the distribution of K atoms on the surface and inside of bio-chars remained uniform, suggesting the efficient formation of active sites for CO2 gasification, although the K content on the surface decreased because of releasing. In contrast, even before heating, the Fe atoms were nonuniformly supported as α-FeOOH and α-Fe2O3 particles on the surface. After heating under an Ar flow, the Fe content on the surface decreased because Fe oxide particles moved into mesopore, suggesting the decrease in the number of active sites and the restriction of the accessibility of CO2 to active sites because of the existence of large Fe oxide particles in mesopores.
The aim of this study was to investigate the effect of gas flow rate on the gas production rate from n-dodecane using steam reforming in-liquid plasma. A steam reforming of n-dodecane was carried out within the reactor vessel which was connected to a waveguide, an aluminum rectangular tubes that guides the propagation of electromagnetic waves with minimum loss of energy. The liquid medium used for plasma generation was n-dodecane (commercial reagent). The tip of a single electrode was positioned in the bottom center of the reactor vessel for plasma formation. The produced gas flowed through an aspirator and was trapped and collected in a water filled container. The gas production rate was measured and its compositions were analyzed using a gas chromatograph. The gas production rate by plasma with steam feeding was 1.4 times greater than that by plasma without steam feeding. The hydrogen content of the gas produced ranged from 73% to 82%. The maximum energy efficiency, as indicated by the ratio of the enthalpy difference of the chemical reactions to the input energy, was approximately 12%. The maximum hydrogen generation efficiency obtained from experiments was up to 59% higher than the efficiency of hydrogen production from electrolysis of alkaline solutions as reported in literatures. The energy payback ratio of hydrogen (EPRH2）was also calculated in order to obtain the hydrogen production efficiency.