Assessment of renewable energy by using GIS - A case study of Unzen City

The purpose of this study is to improve accuracy of the renewable energy assessment in order to promote renewable energy utilization. We have a local renewable energy assessment in the local new energy vision by NEDO. But NEDO assessed potential of local renewable energy with different methods for different energies. Some of these assessments are not accurate enough to decide policy for promoting renewable energy. Therefore, the authors developed a new method of renewable energy assessment and improved the assessment more systematic and accurate by using GIS. The new method evaluates amount of renewable energy as frequency distribution and shows spatial distribution of renewable energy. The authors applied the new method to Unzen City in Nagasaki Prefecture as an example and showed availability of the new method. The result showed that Unzen City has practical potential of 45MWe for geothermal energy, 7.6 MWe for wind energy, 1.1MWe for solar energy and 1.7MWe for small-scale hydropower as a most probable value and that wind and geothermal energy are concentrated to the specific areas and hydropower and solar energy are distributed in whole Unzen City.