Renewable energy is expected to promote energy security, environment, and economic efficiency for the electricity configuration in Japan. The impacts from both economic and environmental aspects have not quantitatively investigated in the case that renewable energy sources are largely installed in the society. In this study, we adopt the input-output analysis as an analytical tool for introduction impact of PV systems. New sectors related to the PV systems, such as “PV module sector”, “BOS sector”, and “PV power generation sector” are created and added to 2005 input-output table for Japan. The extended input-output table allows for estimating the introduction impact in consideration of technical characteristics of PV systems. Based on the hybrid input-output approach, the economic impact and CO₂ emissions of PV systems are analyzed. As a result, it is clarified that (1) the installation of PV systems induce widely production of related industries by the effect of PV manufacturing and construction, and direct and indirect CO₂ emission derived from the PV systems is much lower than that of the other power plants; (2) however, the net amount of added value in industries is offset because there is not only positive impact of production growth due to the manufacturing and construction, but also negative impact of an economic spillover effect caused by the installation of PV systems.

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The oil industry has been grappling with the problem on a heavy oil surplus. Gasification is one of the promising technologies for these issues. Gasification has possibility for high efficiency electric power generation and clean fuel production from heavy oil. The purpose of this study is evaluation of energy production from several heavy oils gasification systems for hydrogen and electricity production using a process simulator. System efficiencies and CO₂ emission intensities was evaluated in this study. We also evaluated the production cost of hydrogen and electricity, and the net present value (NPV) of the gasification system. Furthermore, we compared the production values from gasification systems and heavy oil refining. As the results, the maximum energy efficiency of 56% and the minimum CO₂ emission intensity of 0.44 kg-CO₂ /kWh ware obtained in the hydrogen production system from the atmospheric residue. In the production values, all gasification systems showed superior results than heavy oil refining.

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This paper presents a development measure of energy security evaluation method using mathematical programming and analysis of economic rationality of fuel stockpiles. Faced with the increase of fossil fuels imports due to replacement of nuclear power generation by thermal plants, with the emergence of geopolitical risk in resource rich countries and with the estimation of energy demand growing in developing countries, Japan again found itself as the country whose energy security condition is serious. In these circumstances, development of quantitative energy security measurement method which can deal with relative uncertainties such as fuel price volatility or fuels import disruption as well as the blackout of nuclear power plants. In this paper, the authors firstly specify the mathematical method in which cost minimization bottom-up model using stochastic dynamic programming is constructed. Then the authors show an example of analysis on the economic validity of fuel stockpiles including liquefied natural gas (LNG) stockpiles based on brief assumptions.

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