The objective of the present study is to develop a practical method based on the life cycle approach for assessing environmental and socio-economic impacts induced by utilization of biomass resources in local areas. As the first step, this study analyzes the impacts of bio-ethanol project in Miyakojima city from the viewpoints of fossil fuel consumption, GHG emission and employment creation. In order to assess the impacts of the project, this study compares the two following systems: (1) the Base System where gasoline is consumed as fuels of all gasoline vehicles driven in the city and (2) the E3 System where E3 fuel using bio-ethanol produced in the city is consumed. The results show that the project has the potential to bring the decrease in fossil fuel consumption and GHG emission as well as the increase in the quantity of employment. The analysis also reveals that the reduction of energy required at the ethanol production process is one of the important factors to improve the project.
Renewable energy technologies such as wind power and photovoltaic energy are getting attentions from view points of energy conservation and environmental issue. However, fluctuation of output power of renewable energy may cause excess variation of voltage or frequency of the grid. Increase of the amount of renewable energy would violate the quality of the grid. The micro grid in which dispersed power systems compensate the variation from the renewable energy can expand the installation limit of the renewable energy by maintaining the quality of the interconnected grid. In this paper, evaluation of the ratio of gas turbines is discussed from the point of power flow stability of the grid, efficiency, economy and CO2 emission in a daily load curve. In addition to the discussion in a daily load curve, the number of gas turbines to be in operation is discussed in this paper.