To expand the use of renewable energy, it is necessary to optimize energy production at a local level
through an appropriate combination of different renewable energy resources. Additionally, the environmental
impacts from the use of renewable resources must be considered from different perspectives.
Thus, this study aims to develop a decision tool that evaluates and optimizes the renewable energy mix
at a regional scale with regard to various environmental impacts. This tool was developed by creating a
municipal energy database that includes five renewable energies (solar, wind, small- and medium-scale
hydro, geothermal and biomass energy) and six evaluation indicators (proportion of developed renewable
energy, economic balance, installed wind power, decrease in CO2 emissions, circulation rate of
biomass resource, and impacted ecosystem area). Specifying different constraints in the model allowed
investigation of the optimal renewable energy combination in a study area for two different scenarios,
with the results highlighting the trade-offs between the scenarios.We also optimized the combination of
different renewable energies for every municipality across Japan, while incorporating the natural conditions
and varying demand structure. In conclusion, the tool developed in this study could support
decision-making regarding the development of renewable energy resources.